/*
* Copyright (c) 2007 Mockito contributors
* This program is made available under the terms of the MIT License.
*/
package org.mockito;
import org.mockito.internal.MockitoCore;
import org.mockito.internal.creation.MockSettingsImpl;
import org.mockito.internal.debugging.MockitoDebuggerImpl;
import org.mockito.internal.stubbing.answers.*;
import org.mockito.internal.stubbing.defaultanswers.ReturnsEmptyValues;
import org.mockito.internal.stubbing.defaultanswers.ReturnsMoreEmptyValues;
import org.mockito.internal.verification.VerificationModeFactory;
import org.mockito.runners.MockitoJUnitRunner;
import org.mockito.stubbing.*;
import org.mockito.verification.Timeout;
import org.mockito.verification.VerificationMode;
import org.mockito.verification.VerificationWithTimeout;
/**
* <p align="left"><img src="logo.jpg"/></p>
* Mockito library enables mocks creation, verification and stubbing.
* <p>
* This javadoc content is also available on the <a href="http://mockito.org">http://mockito.org</a> web page.
* All documentation is kept in javadocs because it guarantees consistency between what's on the web and what's in the source code.
* Also, it makes possible to access documentation straight from the IDE even if you work offline.
*
* <h1>Contents</h1>
*
* <b>
* <a href="#1">1. Let's verify some behaviour! </a><br/>
* <a href="#2">2. How about some stubbing? </a><br/>
* <a href="#3">3. Argument matchers </a><br/>
* <a href="#4">4. Verifying exact number of invocations / at least once / never </a><br/>
* <a href="#5">5. Stubbing void methods with exceptions </a><br/>
* <a href="#6">6. Verification in order </a><br/>
* <a href="#7">7. Making sure interaction(s) never happened on mock </a><br/>
* <a href="#8">8. Finding redundant invocations </a><br/>
* <a href="#9">9. Shorthand for mocks creation - @Mock annotation </a><br/>
* <a href="#10">10. Stubbing consecutive calls (iterator-style stubbing) </a><br/>
* <a href="#11">11. Stubbing with callbacks </a><br/>
* <a href="#12">12. doThrow()|doAnswer()|doNothing()|doReturn() family of methods mostly for stubbing voids </a><br/>
* <a href="#13">13. Spying on real objects </a><br/>
* <a href="#14">14. Changing default return values of unstubbed invocations (Since 1.7) </a><br/>
* <a href="#15">15. Capturing arguments for further assertions (Since 1.8.0) </a><br/>
* <a href="#16">16. Real partial mocks (Since 1.8.0) </a><br/>
* <a href="#17">17. Resetting mocks (Since 1.8.0) </a><br/>
* <a href="#18">18. Troubleshooting & validating framework usage (Since 1.8.0) </a><br/>
* <a href="#19">19. Aliases for behavior driven development (Since 1.8.0) </a><br/>
* <a href="#20">20. Serializable mocks (Since 1.8.1) </a><br/>
* <a href="#21">21. New annotations: @Captor, @Spy, @InjectMocks (Since 1.8.3) </a><br/>
* <a href="#22">22. (New) Verification with timeout (Since 1.8.5) </a><br/>
* <a href="#23">23. (**New**) Automatic instantiation of @Spies, @InjectMocks and constructor injection goodness (Since 1.9)</a><br/>
* <a href="#24">24. (**New**) One-liner stubs (Since 1.9)</a><br/>
* <a href="#25">25. (**New**) Verification ignoring stubs (Since 1.9)</a><br/>
* </b>
*
* <p>
* Following examples mock a List, because everyone knows its interface (methods
* like add(), get(), clear() will be used). <br>
* You probably wouldn't mock List class 'in real'.
*
* <h3 id="1">1. Let's verify some behaviour!</h3>
*
* <pre>
* //Let's import Mockito statically so that the code looks clearer
* import static org.mockito.Mockito.*;
*
* //mock creation
* List mockedList = mock(List.class);
*
* //using mock object
* mockedList.add("one");
* mockedList.clear();
*
* //verification
* verify(mockedList).add("one");
* verify(mockedList).clear();
* </pre>
*
* <p>
* Once created, mock will remember all interactions. Then you can selectively
* verify whatever interaction you are interested in.
*
* <h3 id="2">2. How about some stubbing?</h3>
*
* <pre>
* //You can mock concrete classes, not only interfaces
* LinkedList mockedList = mock(LinkedList.class);
*
* //stubbing
* when(mockedList.get(0)).thenReturn("first");
* when(mockedList.get(1)).thenThrow(new RuntimeException());
*
* //following prints "first"
* System.out.println(mockedList.get(0));
*
* //following throws runtime exception
* System.out.println(mockedList.get(1));
*
* //following prints "null" because get(999) was not stubbed
* System.out.println(mockedList.get(999));
*
* //Although it is possible to verify a stubbed invocation, usually <b>it's just redundant</b>
* //If your code cares what get(0) returns then something else breaks (often before even verify() gets executed).
* //If your code doesn't care what get(0) returns then it should not be stubbed. Not convinced? See <a href="http://monkeyisland.pl/2008/04/26/asking-and-telling">here</a>.
* verify(mockedList).get(0);
* </pre>
*
* <ul>
* <li> By default, for all methods that return value, mock returns null, an
* empty collection or appropriate primitive/primitive wrapper value (e.g: 0,
* false, ... for int/Integer, boolean/Boolean, ...). </li>
*
* <li> Stubbing can be overridden: for example common stubbing can go to
* fixture setup but the test methods can override it.
* Please note that overridding stubbing is a potential code smell that points out too much stubbing</li>
*
* <li> Once stubbed, the method will always return stubbed value regardless
* of how many times it is called. </li>
*
* <li> Last stubbing is more important - when you stubbed the same method with
* the same arguments many times.
* Other words: <b>the order of stubbing matters</b> but it is only meaningful rarely,
* e.g. when stubbing exactly the same method calls or sometimes when argument matchers are used, etc.</li>
*
* </ul>
*
* <h3 id="3">3. Argument matchers</h3>
*
* Mockito verifies argument values in natural java style: by using an equals() method.
* Sometimes, when extra flexibility is required then you might use argument matchers:
*
* <pre>
* //stubbing using built-in anyInt() argument matcher
* when(mockedList.get(anyInt())).thenReturn("element");
*
* //stubbing using hamcrest (let's say isValid() returns your own hamcrest matcher):
* when(mockedList.contains(argThat(isValid()))).thenReturn("element");
*
* //following prints "element"
* System.out.println(mockedList.get(999));
*
* //<b>you can also verify using an argument matcher</b>
* verify(mockedList).get(anyInt());
* </pre>
*
* <p>
* Argument matchers allow flexible verification or stubbing.
* {@link Matchers Click here to see} more built-in matchers
* and examples of <b>custom argument matchers / hamcrest matchers</b>.
* <p>
* For information solely on <b>custom argument matchers</b> check out javadoc for {@link ArgumentMatcher} class.
* <p>
* Be reasonable with using complicated argument matching.
* The natural matching style using equals() with occasional anyX() matchers tend to give clean & simple tests.
* Sometimes it's just better to refactor the code to allow equals() matching or even implement equals() method to help out with testing.
* <p>
* Also, read <a href="#15">section 15</a> or javadoc for {@link ArgumentCaptor} class.
* {@link ArgumentCaptor} is a special implementation of an argument matcher that captures argument values for further assertions.
* <p>
* <b>Warning on argument matchers:</b>
* <p>
* If you are using argument matchers, <b>all arguments</b> have to be provided
* by matchers.
* <p>
* E.g: (example shows verification but the same applies to stubbing):
*
* <pre>
* verify(mock).someMethod(anyInt(), anyString(), <b>eq("third argument")</b>);
* //above is correct - eq() is also an argument matcher
*
* verify(mock).someMethod(anyInt(), anyString(), <b>"third argument"</b>);
* //above is incorrect - exception will be thrown because third argument is given without an argument matcher.
* </pre>
*
* <p>
* Matcher methods like anyObject(), eq() <b>do not</b> return matchers.
* Internally, they record a matcher on a stack and return a dummy value (usually null).
* This implementation is due static type safety imposed by java compiler.
* The consequence is that you cannot use anyObject(), eq() methods outside of verified/stubbed method.
*
* <h3 id="4">4. Verifying exact number of invocations / at least x / never</h3>
*
* <pre>
* //using mock
* mockedList.add("once");
*
* mockedList.add("twice");
* mockedList.add("twice");
*
* mockedList.add("three times");
* mockedList.add("three times");
* mockedList.add("three times");
*
* //following two verifications work exactly the same - times(1) is used by default
* verify(mockedList).add("once");
* verify(mockedList, times(1)).add("once");
*
* //exact number of invocations verification
* verify(mockedList, times(2)).add("twice");
* verify(mockedList, times(3)).add("three times");
*
* //verification using never(). never() is an alias to times(0)
* verify(mockedList, never()).add("never happened");
*
* //verification using atLeast()/atMost()
* verify(mockedList, atLeastOnce()).add("three times");
* verify(mockedList, atLeast(2)).add("five times");
* verify(mockedList, atMost(5)).add("three times");
*
* </pre>
*
* <p>
* <b>times(1) is the default.</b> Therefore using times(1) explicitly can be
* omitted.
*
* <h3 id="5">5. Stubbing void methods with exceptions</h3>
*
* <pre>
* doThrow(new RuntimeException()).when(mockedList).clear();
*
* //following throws RuntimeException:
* mockedList.clear();
* </pre>
*
* Read more about doThrow|doAnswer family of methods in paragraph 12.
* <p>
* Initially, {@link Mockito#stubVoid(Object)} was used for stubbing voids.
* Currently stubVoid() is deprecated in favor of {@link Mockito#doThrow(Throwable)}.
* This is because of improved readability and consistency with the family of {@link Mockito#doAnswer(Answer)} methods.
*
* <h3 id="6">6. Verification in order</h3>
*
* <pre>
* // A. Single mock whose methods must be invoked in a particular order
* List singleMock = mock(List.class);
*
* //using a single mock
* singleMock.add("was added first");
* singleMock.add("was added second");
*
* //create an inOrder verifier for a single mock
* InOrder inOrder = inOrder(singleMock);
*
* //following will make sure that add is first called with "was added first, then with "was added second"
* inOrder.verify(singleMock).add("was added first");
* inOrder.verify(singleMock).add("was added second");
*
* // B. Multiple mocks that must be used in a particular order
* List firstMock = mock(List.class);
* List secondMock = mock(List.class);
*
* //using mocks
* firstMock.add("was called first");
* secondMock.add("was called second");
*
* //create inOrder object passing any mocks that need to be verified in order
* InOrder inOrder = inOrder(firstMock, secondMock);
*
* //following will make sure that firstMock was called before secondMock
* inOrder.verify(firstMock).add("was called first");
* inOrder.verify(secondMock).add("was called second");
*
* // Oh, and A + B can be mixed together at will
* </pre>
*
* Verification in order is flexible - <b>you don't have to verify all
* interactions</b> one-by-one but only those that you are interested in
* testing in order.
* <p>
* Also, you can create InOrder object passing only mocks that are relevant for
* in-order verification.
*
* <h3 id="7">7. Making sure interaction(s) never happened on mock</h3>
*
* <pre>
* //using mocks - only mockOne is interacted
* mockOne.add("one");
*
* //ordinary verification
* verify(mockOne).add("one");
*
* //verify that method was never called on a mock
* verify(mockOne, never()).add("two");
*
* //verify that other mocks were not interacted
* verifyZeroInteractions(mockTwo, mockThree);
*
* </pre>
*
* <h3 id="8">8. Finding redundant invocations</h3>
*
* <pre>
* //using mocks
* mockedList.add("one");
* mockedList.add("two");
*
* verify(mockedList).add("one");
*
* //following verification will fail
* verifyNoMoreInteractions(mockedList);
* </pre>
*
* A word of <b>warning</b>:
* Some users who did a lot of classic, expect-run-verify mocking tend to use verifyNoMoreInteractions() very often, even in every test method.
* verifyNoMoreInteractions() is not recommended to use in every test method.
* verifyNoMoreInteractions() is a handy assertion from the interaction testing toolkit. Use it only when it's relevant.
* Abusing it leads to overspecified, less maintainable tests. You can find further reading
* <a href="http://monkeyisland.pl/2008/07/12/should-i-worry-about-the-unexpected/">here</a>.
*
* <p>
* See also {@link Mockito#never()} - it is more explicit and
* communicates the intent well.
* <p>
*
* <h3 id="9">9. Shorthand for mocks creation - @Mock annotation</h3>
*
* <ul>
* <li>Minimizes repetitive mock creation code.</li>
* <li>Makes the test class more readable.</li>
* <li>Makes the verification error easier to read because the <b>field name</b>
* is used to identify the mock.</li>
* </ul>
*
* <pre>
* public class ArticleManagerTest {
*
* @Mock private ArticleCalculator calculator;
* @Mock private ArticleDatabase database;
* @Mock private UserProvider userProvider;
*
* private ArticleManager manager;
* </pre>
*
* <b>Important!</b> This needs to be somewhere in the base class or a test
* runner:
*
* <pre>
* MockitoAnnotations.initMocks(testClass);
* </pre>
*
* You can use built-in runner: {@link MockitoJUnitRunner}.
* <p>
* Read more here: {@link MockitoAnnotations}
*
* <h3 id="10"> 10. Stubbing consecutive calls (iterator-style stubbing)</h3>
*
* Sometimes we need to stub with different return value/exception for the same
* method call. Typical use case could be mocking iterators.
* Original version of Mockito did not have this feature to promote simple mocking.
* For example, instead of iterators one could use {@link Iterable} or simply
* collections. Those offer natural ways of stubbing (e.g. using real
* collections). In rare scenarios stubbing consecutive calls could be useful,
* though:
* <p>
*
* <pre>
* when(mock.someMethod("some arg"))
* .thenThrow(new RuntimeException())
* .thenReturn("foo");
*
* //First call: throws runtime exception:
* mock.someMethod("some arg");
*
* //Second call: prints "foo"
* System.out.println(mock.someMethod("some arg"));
*
* //Any consecutive call: prints "foo" as well (last stubbing wins).
* System.out.println(mock.someMethod("some arg"));
* </pre>
*
* Alternative, shorter version of consecutive stubbing:
*
* <pre>
* when(mock.someMethod("some arg"))
* .thenReturn("one", "two", "three");
* </pre>
*
* <h3 id="11"> 11. Stubbing with callbacks</h3>
*
* Allows stubbing with generic {@link Answer} interface.
* <p>
* Yet another controversial feature which was not included in Mockito
* originally. We recommend using simple stubbing with thenReturn() or
* thenThrow() only. Those two should be <b>just enough</b> to test/test-drive
* any clean & simple code.
*
* <pre>
* when(mock.someMethod(anyString())).thenAnswer(new Answer() {
* Object answer(InvocationOnMock invocation) {
* Object[] args = invocation.getArguments();
* Object mock = invocation.getMock();
* return "called with arguments: " + args;
* }
* });
*
* //Following prints "called with arguments: foo"
* System.out.println(mock.someMethod("foo"));
* </pre>
*
* <h3 id="12"> 12. doThrow()|doAnswer()|doNothing()|doReturn() family of methods for stubbing voids (mostly)</h3>
*
* Stubbing voids requires different approach from {@link Mockito#when(Object)} because the compiler does not like void methods inside brackets...
* <p>
* {@link Mockito#doThrow(Throwable)} replaces the {@link Mockito#stubVoid(Object)} method for stubbing voids.
* The main reason is improved readability and consistency with the family of doAnswer() methods.
* <p>
* Use doThrow() when you want to stub a void method with an exception:
* <pre>
* doThrow(new RuntimeException()).when(mockedList).clear();
*
* //following throws RuntimeException:
* mockedList.clear();
* </pre>
*
* Read more about other methods:
* <p>
* {@link Mockito#doThrow(Throwable)}
* <p>
* {@link Mockito#doAnswer(Answer)}
* <p>
* {@link Mockito#doNothing()}
* <p>
* {@link Mockito#doReturn(Object)}
*
* <h3 id="13"> 13. Spying on real objects</h3>
*
* You can create spies of real objects. When you use the spy then the <b>real</b> methods are called (unless a method was stubbed).
* <p>
* Real spies should be used <b>carefully and occasionally</b>, for example when dealing with legacy code.
*
* <p>
* Spying on real objects can be associated with "partial mocking" concept.
* <b>Before the release 1.8</b>, Mockito spies were not real partial mocks.
* The reason was we thought partial mock is a code smell.
* At some point we found legitimate use cases for partial mocks
* (3rd party interfaces, interim refactoring of legacy code, the full article is <a href=
* "http://monkeyisland.pl/2009/01/13/subclass-and-override-vs-partial-mocking-vs-refactoring"
* >here</a>)
* <p>
*
* <pre>
* List list = new LinkedList();
* List spy = spy(list);
*
* //optionally, you can stub out some methods:
* when(spy.size()).thenReturn(100);
*
* //using the spy calls <b>real</b> methods
* spy.add("one");
* spy.add("two");
*
* //prints "one" - the first element of a list
* System.out.println(spy.get(0));
*
* //size() method was stubbed - 100 is printed
* System.out.println(spy.size());
*
* //optionally, you can verify
* verify(spy).add("one");
* verify(spy).add("two");
* </pre>
*
* <h4>Important gotcha on spying real objects!</h4>
*
* 1. Sometimes it's impossible or impractical to use {@link Mockito#when(Object)} for stubbing spies.
* Therefore when using spies please consider doReturn|Answer|Throw() family of methods for stubbing. Example:
*
* <pre>
* List list = new LinkedList();
* List spy = spy(list);
*
* //Impossible: real method is called so spy.get(0) throws IndexOutOfBoundsException (the list is yet empty)
* when(spy.get(0)).thenReturn("foo");
*
* //You have to use doReturn() for stubbing
* doReturn("foo").when(spy).get(0);
* </pre>
*
* 2. Watch out for final methods.
* Mockito doesn't mock final methods so the bottom line is: when you spy on real objects + you try to stub a final method = trouble.
* What will happen is the real method will be called *on mock* but *not on the real instance* you passed to the spy() method.
* Typically you may get a NullPointerException because mock instances don't have fields initiated.
*
* <h3 id="14">14. Changing default return values of unstubbed invocations (Since 1.7) </h3>
*
* You can create a mock with specified strategy for its return values.
* It's quite advanced feature and typically you don't need it to write decent tests.
* However, it can be helpful for working with <b>legacy systems</b>.
* <p>
* It is the default answer so it will be used <b>only when you don't</b> stub the method call.
*
* <pre>
* Foo mock = mock(Foo.class, Mockito.RETURNS_SMART_NULLS);
* Foo mockTwo = mock(Foo.class, new YourOwnAnswer());
* </pre>
*
* <p>
* Read more about this interesting implementation of <i>Answer</i>: {@link Mockito#RETURNS_SMART_NULLS}
*
* <h3 id="15">15. Capturing arguments for further assertions (Since 1.8.0) </h3>
*
* Mockito verifies argument values in natural java style: by using an equals() method.
* This is also the recommended way of matching arguments because it makes tests clean & simple.
* In some situations though, it is helpful to assert on certain arguments after the actual verification.
* For example:
* <pre>
* ArgumentCaptor<Person> argument = ArgumentCaptor.forClass(Person.class);
* verify(mock).doSomething(argument.capture());
* assertEquals("John", argument.getValue().getName());
* </pre>
*
* <b>Warning:</b> it is recommended to use ArgumentCaptor with verification <b>but not</b> with stubbing.
* Using ArgumentCaptor with stubbing may decrease test readability because captor is created outside of assert (aka verify or 'then') block.
* Also it may reduce defect localization because if stubbed method was not called then no argument is captured.
* <p>
* In a way ArgumentCaptor is related to custom argument matchers (see javadoc for {@link ArgumentMatcher} class).
* Both techniques can be used for making sure certain arguments where passed to mocks.
* However, ArgumentCaptor may be a better fit if:
* <ul>
* <li>custom argument matcher is not likely to be reused</li>
* <li>you just need it to assert on argument values to complete verification</li>
* </ul>
* Custom argument matchers via {@link ArgumentMatcher} are usually better for stubbing.
*
* <h3 id="16">16. Real partial mocks (Since 1.8.0) </h3>
*
* Finally, after many internal debates & discussions on the mailing list, partial mock support was added to Mockito.
* Previously we considered partial mocks as code smells. However, we found a legitimate use case for partial mocks - more reading:
* <a href="http://monkeyisland.pl/2009/01/13/subclass-and-override-vs-partial-mocking-vs-refactoring">here</a>
* <p>
* <b>Before release 1.8</b> spy() was not producing real partial mocks and it was confusing for some users.
* Read more about spying: <a href="#13">here</a> or in javadoc for {@link Mockito#spy(Object)} method.
* <p>
* <pre>
* //you can create partial mock with spy() method:
* List list = spy(new LinkedList());
*
* //you can enable partial mock capabilities selectively on mocks:
* Foo mock = mock(Foo.class);
* //Be sure the real implementation is 'safe'.
* //If real implementation throws exceptions or depends on specific state of the object then you're in trouble.
* when(mock.someMethod()).thenCallRealMethod();
* </pre>
*
* As usual you are going to read <b>the partial mock warning</b>:
* Object oriented programming is more less tackling complexity by dividing the complexity into separate, specific, SRPy objects.
* How does partial mock fit into this paradigm? Well, it just doesn't...
* Partial mock usually means that the complexity has been moved to a different method on the same object.
* In most cases, this is not the way you want to design your application.
* <p>
* However, there are rare cases when partial mocks come handy:
* dealing with code you cannot change easily (3rd party interfaces, interim refactoring of legacy code etc.)
* However, I wouldn't use partial mocks for new, test-driven & well-designed code.
*
* <h3 id="17">17. Resetting mocks (Since 1.8.0) </h3>
*
* Smart Mockito users hardly use this feature because they know it could be a sign of poor tests.
* Normally, you don't need to reset your mocks, just create new mocks for each test method.
* <p>
* Instead of reset() please consider writing simple, small and focused test methods over lengthy, over-specified tests.
* <b>First potential code smell is reset() in the middle of the test method.</b> This probably means you're testing too much.
* Follow the whisper of your test methods: "Please keep us small & focused on single behavior".
* There are several threads about it on mockito mailing list.
* <p>
* The only reason we added reset() method is to
* make it possible to work with container-injected mocks.
* See issue 55 (<a href="http://code.google.com/p/mockito/issues/detail?id=55">here</a>)
* or FAQ (<a href="http://code.google.com/p/mockito/wiki/FAQ">here</a>).
* <p>
* <b>Don't harm yourself.</b> reset() in the middle of the test method is a code smell (you're probably testing too much).
* <pre>
* List mock = mock(List.class);
* when(mock.size()).thenReturn(10);
* mock.add(1);
*
* reset(mock);
* //at this point the mock forgot any interactions & stubbing
* </pre>
*
* <h3 id="18">18. Troubleshooting & validating framework usage (Since 1.8.0) </h3>
*
* First of all, in case of any trouble, I encourage you to read the Mockito FAQ:
* <a href="http://code.google.com/p/mockito/wiki/FAQ">http://code.google.com/p/mockito/wiki/FAQ</a>
* <p>
* In case of questions you may also post to mockito mailing list:
* <a href="http://groups.google.com/group/mockito">http://groups.google.com/group/mockito</a>
* <p>
* Next, you should know that Mockito validates if you use it correctly <b>all the time</b>.
* However, there's a gotcha so please read the javadoc for {@link Mockito#validateMockitoUsage()}
*
* <h3 id="19">19. Aliases for behavior driven development (Since 1.8.0) </h3>
*
* Behavior Driven Development style of writing tests uses <b>//given //when //then</b> comments as fundamental parts of your test methods.
* This is exactly how we write our tests and we warmly encourage you to do so!
* <p>
* Start learning about BDD here: <a href="http://en.wikipedia.org/wiki/Behavior_Driven_Development">http://en.wikipedia.org/wiki/Behavior_Driven_Development</a>
* <p>
* The problem is that current stubbing api with canonical role of <b>when</b> word does not integrate nicely with <b>//given //when //then</b> comments.
* It's because stubbing belongs to <b>given</b> component of the test and not to the <b>when</b> component of the test.
* Hence {@link BDDMockito} class introduces an alias so that you stub method calls with {@link BDDMockito#given(Object)} method.
* Now it really nicely integrates with the <b>given</b> component of a BDD style test!
* <p>
* Here is how the test might look like:
* <pre>
* import static org.mockito.BDDMockito.*;
*
* Seller seller = mock(Seller.class);
* Shop shop = new Shop(seller);
*
* public void shouldBuyBread() throws Exception {
* //given
* given(seller.askForBread()).willReturn(new Bread());
*
* //when
* Goods goods = shop.buyBread();
*
* //then
* assertThat(goods, containBread());
* }
* </pre>
*
* <h3 id="20">20. (**New**) Serializable mocks (Since 1.8.1) </h3>
*
* Mocks can be made serializable. With this feature you can use a mock in a place that requires dependencies to be serializable.
* <p>
* WARNING: This should be rarely used in unit testing.
* <p>
* The behaviour was implemented for a specific use case of a BDD spec that had an unreliable external dependency. This
* was in a web environment and the objects from the external dependency were being serialized to pass between layers.
* <p>
* To create serializable mock use {@link MockSettings#serializable()}:
* <pre>
* List serializableMock = mock(List.class, withSettings().serializable());
* </pre>
* <p>
* The mock can be serialized assuming all the normal <a href='http://java.sun.com/j2se/1.5.0/docs/api/java/io/Serializable.html'>
* serialization requirements</a> are met by the class.
* <p>
* Making a real object spy serializable is a bit more effort as the spy(...) method does not have an overloaded version
* which accepts MockSettings. No worries, you will hardly ever use it.
*
* <pre>
* List<Object> list = new ArrayList<Object>();
* List<Object> spy = mock(ArrayList.class, withSettings()
* .spiedInstance(list)
* .defaultAnswer(CALLS_REAL_METHODS)
* .serializable());
* </pre>
*
* <h3 id="21">21. (**New**) New annotations: @Captor, @Spy, @InjectMocks (Since 1.8.3) </h3>
* <p>
* Release 1.8.3 brings new annotations that may be helpful on occasion:
*
* <ul>
* <li>@{@link Captor} simplifies creation of {@link ArgumentCaptor}
* - useful when the argument to capture is a nasty generic class and you want to avoid compiler warnings
* <li>@{@link Spy} - you can use it instead {@link Mockito#spy(Object)}.
* <li>@{@link InjectMocks} - injects mock or spy fields into tested object automatically.
* </ul>
*
* <p>
* Note that @{@link InjectMocks} can only be used in combination with the @{@link Spy} annotation, it means
* that Mockito will inject mocks in a partial mock under testing. As a remainder, please read point 16 about partial mocks.
*
* <p>
* All new annotations are *only* processed on {@link MockitoAnnotations#initMocks(Object)}.
* Just like for @{@link Mock} annotation you can use the built-in runner: {@link MockitoJUnitRunner}.
* <p>
* <h3 id="22">22. (**New**) Verification with timeout (Since 1.8.5) </h3>
* <p>
* Allows verifying with timeout. May be useful for testing in concurrent conditions.
* <p>
* It feels this feature should be used rarely - figure out a better way of testing your multi-threaded system.
* <p>
* Not yet implemented to work with InOrder verification.
* <p>
* Examples:
* <p>
* <pre>
* //passes when someMethod() is called within given time span
* verify(mock, timeout(100)).someMethod();
* //above is an alias to:
* verify(mock, timeout(100).times(1)).someMethod();
*
* //passes when someMethod() is called *exactly* 2 times within given time span
* verify(mock, timeout(100).times(2)).someMethod();
*
* //passes when someMethod() is called *at lest* 2 times within given time span
* verify(mock, timeout(100).atLeast(2)).someMethod();
*
* //verifies someMethod() within given time span using given verification mode
* //useful only if you have your own custom verification modes.
* verify(mock, new Timeout(100, yourOwnVerificationMode)).someMethod();
* </pre>
*
* <h3 id="23">23. (**New**) Automatic instantiation of @Spies, @InjectMocks and constructor injection goodness (Since 1.9)</h3>
* <p>
* Mockito will now try to instantiate @{@link Spy} and will instantiate @{@link InjectMocks} fields
* using <b>constructor</b> injection, <b>setter</b> injection, or <b>field</b> injection.
* <p>
* To take advantage of this feature you need to use {@link MockitoAnnotations#initMocks(Object)} or {@link MockitoJUnitRunner}.
* <p>
* Read more about available tricks and the rules of injection in the javadoc for {@link InjectMocks}
* <pre>
* //instead:
* @Spy BeerDrinker drinker = new BeerDrinker();
* //you can write:
* @Spy BeerDrinker drinker;
*
* //same applies to @InjectMocks annotation:
* @InjectMocks LocalPub;
* </pre>
*
* <h3 id="24">24. (**New**) One-liner stubs (Since 1.9)</h3>
* <p>
* Mockito will now allow you to create mocks when stubbing.
* Basically, it allows to create a stub in one line of code.
* This can be helpful to keep test code clean.
* For example, some boring stub can be created & stubbed at field initialization in a test:
* <pre>
* public class CarTest {
* Car boringStubbedCar = when(mock(Car.class).shiftGear()).thenThrow(EngineNotStarted.class).getMock();
*
* @Test public void should... {}
* </pre>
*
* <h3 id="25">25. Verification ignoring stubs (Since 1.9)</h3>
* <p>
* Mockito will now allow to ignore stubbing for the sake of verification.
* Sometimes useful when coupled with verifyNoMoreInteractions() or verification inOrder().
* Helps avoiding redundant verification of stubbed calls - typically we're not interested in verifying stubs.
* <p>
* <b>Warning</b>, ignoreStubs() might lead to overuse of verifyNoMoreInteractions(ignoreStubs(...));
* Bear in mind that Mockito does not recommend bombarding every test with verifyNoMoreInteractions()
* for the reasons outlined in javadoc for {@link Mockito#verifyNoMoreInteractions(Object...)}
* <p>Some examples:
* <pre>
* verify(mock).foo();
* verify(mockTwo).bar();
*
* //ignores all stubbed methods:
* verifyNoMoreInvocations(ignoreStubs(mock, mockTwo));
*
* //creates InOrder that will ignore stubbed
* InOrder inOrder = inOrder(ignoreStubs(mock, mockTwo));
* inOrder.verify(mock).foo();
* inOrder.verify(mockTwo).bar();
* inOrder.verifyNoMoreInteractions();
* </pre>
* <p>
* Advanced examples and more details can be found in javadoc for {@link Mockito#ignoreStubs(Object...)}
*/
@SuppressWarnings("unchecked")
public class Mockito extends Matchers {
static final MockitoCore MOCKITO_CORE = new MockitoCore();
/**
* The default Answer of every mock <b>if</b> the mock was not stubbed.
* Typically it just returns some empty value.
* <p>
* {@link Answer} can be used to define the return values of unstubbed invocations.
* <p>
* This implementation first tries the global configuration.
* If there is no global configuration then it uses {@link ReturnsEmptyValues} (returns zeros, empty collections, nulls, etc.)
*/
public static final Answer<Object> RETURNS_DEFAULTS = Answers.RETURNS_DEFAULTS.get();
/**
* Optional Answer to be used with {@link Mockito#mock(Class, Answer)}
* <p>
* {@link Answer} can be used to define the return values of unstubbed invocations.
* <p>
* This implementation can be helpful when working with legacy code.
* Unstubbed methods often return null. If your code uses the object returned by an unstubbed call you get a NullPointerException.
* This implementation of Answer <b>returns SmartNull instead of null</b>.
* SmartNull gives nicer exception message than NPE because it points out the line where unstubbed method was called. You just click on the stack trace.
* <p>
* ReturnsSmartNulls first tries to return ordinary return values (see {@link ReturnsMoreEmptyValues})
* then it tries to return SmartNull. If the return type is final then plain null is returned.
* <p>
* ReturnsSmartNulls will be probably the default return values strategy in Mockito 2.0
* <p>
* Example:
* <pre>
* Foo mock = (Foo.class, RETURNS_SMART_NULLS);
*
* //calling unstubbed method here:
* Stuff stuff = mock.getStuff();
*
* //using object returned by unstubbed call:
* stuff.doSomething();
*
* //Above doesn't yield NullPointerException this time!
* //Instead, SmartNullPointerException is thrown.
* //Exception's cause links to unstubbed <i>mock.getStuff()</i> - just click on the stack trace.
* </pre>
*/
public static final Answer<Object> RETURNS_SMART_NULLS = Answers.RETURNS_SMART_NULLS.get();
/**
* Optional Answer to be used with {@link Mockito#mock(Class, Answer)}
* <p>
* {@link Answer} can be used to define the return values of unstubbed invocations.
* <p>
* This implementation can be helpful when working with legacy code.
* <p>
* ReturnsMocks first tries to return ordinary return values (see {@link ReturnsMoreEmptyValues})
* then it tries to return mocks. If the return type cannot be mocked (e.g. is final) then plain null is returned.
* <p>
*/
public static final Answer<Object> RETURNS_MOCKS = Answers.RETURNS_MOCKS.get();
/**
* Optional Answer to be used with {@link Mockito#mock(Class, Answer)}
* <p>
* Example that shows how deep stub works:
* <pre>
* Foo mock = mock(Foo.class, RETURNS_DEEP_STUBS);
*
* // note that we're stubbing a chain of methods here: getBar().getName()
* when(mock.getBar().getName()).thenReturn("deep");
*
* // note that we're chaining method calls: getBar().getName()
* assertEquals("deep", mock.getBar().getName());
* </pre>
*
* <strong>Verification API does not support 'chaining'</strong> so deep stub doesn't change how you do verification.
* <p>
* <strong>WARNING: </strong>
* This feature should rarely be required for regular clean code! Leave it for legacy code.
* Mocking a mock to return a mock, to return a mock, (...), to return something meaningful
* hints at violation of Law of Demeter or mocking a value object (a well known anti-pattern).
* <p>
* Good quote I've seen one day on the web: <strong>every time a mock returns a mock a fairy dies</strong>.
* <p>
* How deep stub work internally?
* <pre>
* //this:
* Foo mock = mock(Foo.class, RETURNS_DEEP_STUBS);
* when(mock.getBar().getName(), "deep");
*
* //is equivalent of
* Foo foo = mock(Foo.class);
* Bar bar = mock(Bar.class);
* when(foo.getBar()).thenReturn(bar);
* when(bar.getName()).thenReturn("deep");
* </pre>
* <p>
* This feature will not work when any return type of methods included in the chain cannot be mocked
* (for example: is a primitive or a final class). This is because of java type system.
*/
public static final Answer<Object> RETURNS_DEEP_STUBS = Answers.RETURNS_DEEP_STUBS.get();
/**
* Optional Answer to be used with {@link Mockito#mock(Class, Answer)}
* <p>
* {@link Answer} can be used to define the return values of unstubbed invocations.
* <p>
* This implementation can be helpful when working with legacy code.
* When this implementation is used, unstubbed methods will delegate to the real implementation.
* This is a way to create a partial mock object that calls real methods by default.
* <p>
* As usual you are going to read <b>the partial mock warning</b>:
* Object oriented programming is more less tackling complexity by dividing the complexity into separate, specific, SRPy objects.
* How does partial mock fit into this paradigm? Well, it just doesn't...
* Partial mock usually means that the complexity has been moved to a different method on the same object.
* In most cases, this is not the way you want to design your application.
* <p>
* However, there are rare cases when partial mocks come handy:
* dealing with code you cannot change easily (3rd party interfaces, interim refactoring of legacy code etc.)
* However, I wouldn't use partial mocks for new, test-driven & well-designed code.
* <p>
* Example:
* <pre>
* Foo mock = mock(Foo.class, CALLS_REAL_METHODS);
*
* // this calls the real implementation of Foo.getSomething()
* value = mock.getSomething();
*
* when(mock.getSomething()).thenReturn(fakeValue);
*
* // now fakeValue is returned
* value = mock.getSomething();
* </pre>
*/
public static final Answer<Object> CALLS_REAL_METHODS = Answers.CALLS_REAL_METHODS.get();
/**
* Creates mock object of given class or interface.
* <p>
* See examples in javadoc for {@link Mockito} class
*
* @param classToMock class or interface to mock
* @return mock object
*/
public static <T> T mock(Class<T> classToMock) {
return mock(classToMock, withSettings().defaultAnswer(RETURNS_DEFAULTS));
}
/**
* Specifies mock name. Naming mocks can be helpful for debugging - the name is used in all verification errors.
* <p>
* Beware that naming mocks is not a solution for complex code which uses too many mocks or collaborators.
* <b>If you have too many mocks then refactor the code</b> so that it's easy to test/debug without necessity of naming mocks.
* <p>
* <b>If you use @Mock annotation then you've got naming mocks for free!</b> @Mock uses field name as mock name. {@link Mock Read more.}
* <p>
*
* See examples in javadoc for {@link Mockito} class
*
* @param classToMock class or interface to mock
* @param name of the mock
* @return mock object
*/
public static <T> T mock(Class<T> classToMock, String name) {
return mock(classToMock, withSettings()
.name(name)
.defaultAnswer(RETURNS_DEFAULTS));
}
/**
* @deprecated
* <b>Please use mock(Foo.class, defaultAnswer);</b>
* <p>
* See {@link Mockito#mock(Class, Answer)}
* <p>
* Why it is deprecated? ReturnValues is being replaced by Answer
* for better consistency & interoperability of the framework.
* Answer interface has been in Mockito for a while and it has the same responsibility as ReturnValues.
* There's no point in mainting exactly the same interfaces.
* <p>
* Creates mock with a specified strategy for its return values.
* It's quite advanced feature and typically you don't need it to write decent tests.
* However it can be helpful when working with legacy systems.
* <p>
* Obviously return values are used only when you don't stub the method call.
*
* <pre>
* Foo mock = mock(Foo.class, Mockito.RETURNS_SMART_NULLS);
* Foo mockTwo = mock(Foo.class, new YourOwnReturnValues());
* </pre>
*
* <p>See examples in javadoc for {@link Mockito} class</p>
*
* @param classToMock class or interface to mock
* @param returnValues default return values for unstubbed methods
*
* @return mock object
*/
@Deprecated
public static <T> T mock(Class<T> classToMock, ReturnValues returnValues) {
return mock(classToMock, withSettings().defaultAnswer(new AnswerReturnValuesAdapter(returnValues)));
}
/**
* Creates mock with a specified strategy for its answers to interactions.
* It's quite advanced feature and typically you don't need it to write decent tests.
* However it can be helpful when working with legacy systems.
* <p>
* It is the default answer so it will be used <b>only when you don't</b> stub the method call.
*
* <pre>
* Foo mock = mock(Foo.class, RETURNS_SMART_NULLS);
* Foo mockTwo = mock(Foo.class, new YourOwnAnswer());
* </pre>
*
* <p>See examples in javadoc for {@link Mockito} class</p>
*
* @param classToMock class or interface to mock
* @param defaultAnswer default answer for unstubbed methods
*
* @return mock object
*/
public static <T> T mock(Class<T> classToMock, Answer defaultAnswer) {
return mock(classToMock, withSettings().defaultAnswer(defaultAnswer));
}
/**
* Creates a mock with some non-standard settings.
* <p>
* The number of configuration points for a mock grows
* so we need a fluent way to introduce new configuration without adding more and more overloaded Mockito.mock() methods.
* Hence {@link MockSettings}.
* <pre>
* Listener mock = mock(Listener.class, withSettings()
* .name("firstListner").defaultBehavior(RETURNS_SMART_NULLS));
* );
* </pre>
* <b>Use it carefully and occasionally</b>. What might be reason your test needs non-standard mocks?
* Is the code under test so complicated that it requires non-standard mocks?
* Wouldn't you prefer to refactor the code under test so it is testable in a simple way?
* <p>
* See also {@link Mockito#withSettings()}
* <p>
* See examples in javadoc for {@link Mockito} class
*
* @param classToMock class or interface to mock
* @param mockSettings additional mock settings
* @return mock object
*/
public static <T> T mock(Class<T> classToMock, MockSettings mockSettings) {
return MOCKITO_CORE.mock(classToMock, mockSettings);
}
/**
* Creates a spy of the real object. The spy calls <b>real</b> methods unless they are stubbed.
* <p>
* Real spies should be used <b>carefully and occasionally</b>, for example when dealing with legacy code.
* <p>
* As usual you are going to read <b>the partial mock warning</b>:
* Object oriented programming is more less tackling complexity by dividing the complexity into separate, specific, SRPy objects.
* How does partial mock fit into this paradigm? Well, it just doesn't...
* Partial mock usually means that the complexity has been moved to a different method on the same object.
* In most cases, this is not the way you want to design your application.
* <p>
* However, there are rare cases when partial mocks come handy:
* dealing with code you cannot change easily (3rd party interfaces, interim refactoring of legacy code etc.)
* However, I wouldn't use partial mocks for new, test-driven & well-designed code.
* <p>
* Example:
*
* <pre>
* List list = new LinkedList();
* List spy = spy(list);
*
* //optionally, you can stub out some methods:
* when(spy.size()).thenReturn(100);
*
* //using the spy calls <b>real</b> methods
* spy.add("one");
* spy.add("two");
*
* //prints "one" - the first element of a list
* System.out.println(spy.get(0));
*
* //size() method was stubbed - 100 is printed
* System.out.println(spy.size());
*
* //optionally, you can verify
* verify(spy).add("one");
* verify(spy).add("two");
* </pre>
*
* <h4>Important gotcha on spying real objects!</h4>
*
* 1. Sometimes it's impossible or impractical to use {@link Mockito#when(Object)} for stubbing spies.
* Therefore when using spies please consider doReturn|Answer|Throw() family of methods for stubbing. Example:
*
* <pre>
* List list = new LinkedList();
* List spy = spy(list);
*
* //Impossible: real method is called so spy.get(0) throws IndexOutOfBoundsException (the list is yet empty)
* when(spy.get(0)).thenReturn("foo");
*
* //You have to use doReturn() for stubbing
* doReturn("foo").when(spy).get(0);
* </pre>
*
* 2. Watch out for final methods.
* Mockito doesn't mock final methods so the bottom line is: when you spy on real objects + you try to stub a final method = trouble.
* What will happen is the real method will be called *on mock* but *not on the real instance* you passed to the spy() method.
* Typically you may get a NullPointerException because mock instances don't have fields initiated.
*
* <p>
* See examples in javadoc for {@link Mockito} class
*
* @param object
* to spy on
* @return a spy of the real object
*/
public static <T> T spy(T object) {
return MOCKITO_CORE.mock((Class<T>) object.getClass(), withSettings()
.spiedInstance(object)
.defaultAnswer(CALLS_REAL_METHODS));
}
/**
* Stubs a method call with return value or an exception. E.g:
*
* <pre>
* stub(mock.someMethod()).toReturn(10);
*
* //you can use flexible argument matchers, e.g:
* stub(mock.someMethod(<b>anyString()</b>)).toReturn(10);
*
* //setting exception to be thrown:
* stub(mock.someMethod("some arg")).toThrow(new RuntimeException());
*
* //you can stub with different behavior for consecutive method calls.
* //Last stubbing (e.g: toReturn("foo")) determines the behavior for further consecutive calls.
* stub(mock.someMethod("some arg"))
* .toThrow(new RuntimeException())
* .toReturn("foo");
* </pre>
* <p>
* Some users find stub() confusing therefore {@link Mockito#when(Object)} is recommended over stub()
* <pre>
* //Instead of:
* stub(mock.count()).toReturn(10);
*
* //You can do:
* when(mock.count()).thenReturn(10);
* </pre>
* For stubbing void methods with throwables see: {@link Mockito#doThrow(Throwable)}
* <p>
* Stubbing can be overridden: for example common stubbing can go to fixture
* setup but the test methods can override it.
* Please note that overridding stubbing is a potential code smell that points out too much stubbing.
* <p>
* Once stubbed, the method will always return stubbed value regardless
* of how many times it is called.
* <p>
* Last stubbing is more important - when you stubbed the same method with
* the same arguments many times.
* <p>
* Although it is possible to verify a stubbed invocation, usually <b>it's just redundant</b>.
* Let's say you've stubbed foo.bar().
* If your code cares what foo.bar() returns then something else breaks(often before even verify() gets executed).
* If your code doesn't care what get(0) returns then it should not be stubbed.
* Not convinced? See <a href="http://monkeyisland.pl/2008/04/26/asking-and-telling">here</a>.
*
* @param methodCall
* method call
* @return DeprecatedOngoingStubbing object to set stubbed value/exception
*/
public static <T> DeprecatedOngoingStubbing<T> stub(T methodCall) {
return MOCKITO_CORE.stub(methodCall);
}
/**
* Enables stubbing methods. Use it when you want the mock to return particular value when particular method is called.
* <p>
* Simply put: "<b>When</b> the x method is called <b>then</b> return y".
* <p>
* <b>when() is a successor of deprecated {@link Mockito#stub(Object)}</b>
* <p>
* Examples:
*
* <pre>
* <b>when</b>(mock.someMethod()).<b>thenReturn</b>(10);
*
* //you can use flexible argument matchers, e.g:
* when(mock.someMethod(<b>anyString()</b>)).thenReturn(10);
*
* //setting exception to be thrown:
* when(mock.someMethod("some arg")).thenThrow(new RuntimeException());
*
* //you can set different behavior for consecutive method calls.
* //Last stubbing (e.g: thenReturn("foo")) determines the behavior of further consecutive calls.
* when(mock.someMethod("some arg"))
* .thenThrow(new RuntimeException())
* .thenReturn("foo");
*
* //Alternative, shorter version for consecutive stubbing:
* when(mock.someMethod("some arg"))
* .thenReturn("one", "two");
* //is the same as:
* when(mock.someMethod("some arg"))
* .thenReturn("one")
* .thenReturn("two");
*
* //shorter version for consecutive method calls throwing exceptions:
* when(mock.someMethod("some arg"))
* .thenThrow(new RuntimeException(), new NullPointerException();
*
* </pre>
*
* For stubbing void methods with throwables see: {@link Mockito#doThrow(Throwable)}
* <p>
* Stubbing can be overridden: for example common stubbing can go to fixture
* setup but the test methods can override it.
* Please note that overridding stubbing is a potential code smell that points out too much stubbing.
* <p>
* Once stubbed, the method will always return stubbed value regardless
* of how many times it is called.
* <p>
* Last stubbing is more important - when you stubbed the same method with
* the same arguments many times.
* <p>
* Although it is possible to verify a stubbed invocation, usually <b>it's just redundant</b>.
* Let's say you've stubbed foo.bar().
* If your code cares what foo.bar() returns then something else breaks(often before even verify() gets executed).
* If your code doesn't care what get(0) returns then it should not be stubbed.
* Not convinced? See <a href="http://monkeyisland.pl/2008/04/26/asking-and-telling">here</a>.
*
* <p>
* See examples in javadoc for {@link Mockito} class
* @param methodCall method to be stubbed
*/
public static <T> OngoingStubbing<T> when(T methodCall) {
return MOCKITO_CORE.when(methodCall);
}
/**
* Verifies certain behavior <b>happened once</b>
* <p>
* Alias to <code>verify(mock, times(1))</code> E.g:
* <pre>
* verify(mock).someMethod("some arg");
* </pre>
* Above is equivalent to:
* <pre>
* verify(mock, times(1)).someMethod("some arg");
* </pre>
* <p>
* Arguments passed are compared using equals() method.
* Read about {@link ArgumentCaptor} or {@link ArgumentMatcher} to find out other ways of matching / asserting arguments passed.
* <p>
* Although it is possible to verify a stubbed invocation, usually <b>it's just redundant</b>.
* Let's say you've stubbed foo.bar().
* If your code cares what foo.bar() returns then something else breaks(often before even verify() gets executed).
* If your code doesn't care what get(0) returns then it should not be stubbed.
* Not convinced? See <a href="http://monkeyisland.pl/2008/04/26/asking-and-telling">here</a>.
*
* <p>
* See examples in javadoc for {@link Mockito} class
*
* @param mock to be verified
* @return mock object itself
*/
public static <T> T verify(T mock) {
return MOCKITO_CORE.verify(mock, times(1));
}
/**
* Verifies certain behavior happened at least once / exact number of times / never. E.g:
* <pre>
* verify(mock, times(5)).someMethod("was called five times");
*
* verify(mock, atLeast(2)).someMethod("was called at least two times");
*
* //you can use flexible argument matchers, e.g:
* verify(mock, atLeastOnce()).someMethod(<b>anyString()</b>);
* </pre>
*
* <b>times(1) is the default</b> and can be omitted
* <p>
* Arguments passed are compared using equals() method.
* Read about {@link ArgumentCaptor} or {@link ArgumentMatcher} to find out other ways of matching / asserting arguments passed.
* <p>
*
* @param mock to be verified
* @param mode times(x), atLeastOnce() or never()
*
* @return mock object itself
*/
public static <T> T verify(T mock, VerificationMode mode) {
return MOCKITO_CORE.verify(mock, mode);
}
/**
* Smart Mockito users hardly use this feature because they know it could be a sign of poor tests.
* Normally, you don't need to reset your mocks, just create new mocks for each test method.
* <p>
* Instead of reset() please consider writing simple, small and focused test methods over lengthy, over-specified tests.
* <b>First potential code smell is reset() in the middle of the test method.</b> This probably means you're testing too much.
* Follow the whisper of your test methods: "Please keep us small & focused on single behavior".
* There are several threads about it on mockito mailing list.
* <p>
* The only reason we added reset() method is to
* make it possible to work with container-injected mocks.
* See issue 55 (<a href="http://code.google.com/p/mockito/issues/detail?id=55">here</a>)
* or FAQ (<a href="http://code.google.com/p/mockito/wiki/FAQ">here</a>).
* <p>
* <b>Don't harm yourself.</b> reset() in the middle of the test method is a code smell (you're probably testing too much).
* <pre>
* List mock = mock(List.class);
* when(mock.size()).thenReturn(10);
* mock.add(1);
*
* reset(mock);
* //at this point the mock forgot any interactions & stubbing
* </pre>
*
* @param <T>
* @param mocks to be reset
*/
public static <T> void reset(T ... mocks) {
MOCKITO_CORE.reset(mocks);
}
/**
* Checks if any of given mocks has any unverified interaction.
* <p>
* You can use this method after you verified your mocks - to make sure that nothing
* else was invoked on your mocks.
* <p>
* See also {@link Mockito#never()} - it is more explicit and communicates the intent well.
* <p>
* Stubbed invocations (if called) are also treated as interactions.
* <p>
* A word of <b>warning</b>:
* Some users who did a lot of classic, expect-run-verify mocking tend to use verifyNoMoreInteractions() very often, even in every test method.
* verifyNoMoreInteractions() is not recommended to use in every test method.
* verifyNoMoreInteractions() is a handy assertion from the interaction testing toolkit. Use it only when it's relevant.
* Abusing it leads to overspecified, less maintainable tests. You can find further reading
* <a href="http://monkeyisland.pl/2008/07/12/should-i-worry-about-the-unexpected/">here</a>.
* <p>
* This method will also detect unverified invocations that occurred before the test method,
* for example: in setUp(), @Before method or in constructor.
* Consider writing nice code that makes interactions only in test methods.
*
* <p>
* Example:
*
* <pre>
* //interactions
* mock.doSomething();
* mock.doSomethingUnexpected();
*
* //verification
* verify(mock).doSomething();
*
* //following will fail because 'doSomethingUnexpected()' is unexpected
* verifyNoMoreInteractions(mock);
*
* </pre>
*
* See examples in javadoc for {@link Mockito} class
*
* @param mocks to be verified
*/
public static void verifyNoMoreInteractions(Object... mocks) {
MOCKITO_CORE.verifyNoMoreInteractions(mocks);
}
/**
* Verifies that no interactions happened on given mocks.
* <pre>
* verifyZeroInteractions(mockOne, mockTwo);
* </pre>
* This method will also detect invocations
* that occurred before the test method, for example: in setUp(), @Before method or in constructor.
* Consider writing nice code that makes interactions only in test methods.
* <p>
* See also {@link Mockito#never()} - it is more explicit and communicates the intent well.
* <p>
* See examples in javadoc for {@link Mockito} class
*
* @param mocks to be verified
*/
public static void verifyZeroInteractions(Object... mocks) {
MOCKITO_CORE.verifyNoMoreInteractions(mocks);
}
/**
* <pre>
* //Instead of:
* stubVoid(mock).toThrow(e).on().someVoidMethod();
*
* //Please do:
* doThrow(e).when(mock).someVoidMethod();
* </pre>
*
* doThrow() replaces stubVoid() because of improved readability and consistency with the family of doAnswer() methods.
* <p>
* Originally, stubVoid() was used for stubbing void methods with exceptions. E.g:
*
* <pre>
* stubVoid(mock).toThrow(new RuntimeException()).on().someMethod();
*
* //you can stub with different behavior for consecutive calls.
* //Last stubbing (e.g. toReturn()) determines the behavior for further consecutive calls.
* stubVoid(mock)
* .toThrow(new RuntimeException())
* .toReturn()
* .on().someMethod();
* </pre>
*
* See examples in javadoc for {@link Mockito} class
*
* @deprecated Use {@link Mockito#doThrow(Throwable)} method for stubbing voids
*
* @param mock
* to stub
* @return stubbable object that allows stubbing with throwable
*/
public static <T> VoidMethodStubbable<T> stubVoid(T mock) {
return MOCKITO_CORE.stubVoid(mock);
}
/**
* Use doThrow() when you want to stub the void method with an exception.
* <p>
* Stubbing voids requires different approach from {@link Mockito#when(Object)} because the compiler does not like void methods inside brackets...
* <p>
* Example:
*
* <pre>
* doThrow(new RuntimeException()).when(mock).someVoidMethod();
* </pre>
*
* @param toBeThrown to be thrown when the stubbed method is called
* @return stubber - to select a method for stubbing
*/
public static Stubber doThrow(Throwable toBeThrown) {
return MOCKITO_CORE.doAnswer(new ThrowsException(toBeThrown));
}
/**
* Use doThrow() when you want to stub the void method to throw exception of specified class.
* <p>
* A new exception instance will be created for each method invocation.
* <p>
* Stubbing voids requires different approach from {@link Mockito#when(Object)} because the compiler does not like void methods inside brackets...
* <p>
* Example:
*
* <pre>
* doThrow(RuntimeException.class).when(mock).someVoidMethod();
* </pre>
*
* @param toBeThrown to be thrown when the stubbed method is called
* @return stubber - to select a method for stubbing
*/
public static Stubber doThrow(Class<? extends Throwable> toBeThrown) {
return MOCKITO_CORE.doAnswer(new ThrowsExceptionClass(toBeThrown));
}
/**
* Use doCallRealMethod() when you want to call the real implementation of a method.
* <p>
* As usual you are going to read <b>the partial mock warning</b>:
* Object oriented programming is more less tackling complexity by dividing the complexity into separate, specific, SRPy objects.
* How does partial mock fit into this paradigm? Well, it just doesn't...
* Partial mock usually means that the complexity has been moved to a different method on the same object.
* In most cases, this is not the way you want to design your application.
* <p>
* However, there are rare cases when partial mocks come handy:
* dealing with code you cannot change easily (3rd party interfaces, interim refactoring of legacy code etc.)
* However, I wouldn't use partial mocks for new, test-driven & well-designed code.
* <p>
* See also javadoc {@link Mockito#spy(Object)} to find out more about partial mocks.
* <b>Mockito.spy() is a recommended way of creating partial mocks.</b>
* The reason is it guarantees real methods are called against correctly constructed object because you're responsible for constructing the object passed to spy() method.
* <p>
* Example:
* <pre>
* Foo mock = mock(Foo.class);
* doCallRealMethod().when(mock).someVoidMethod();
*
* // this will call the real implementation of Foo.someVoidMethod()
* mock.someVoidMethod();
* </pre>
* <p>
* See examples in javadoc for {@link Mockito} class
*
* @return stubber - to select a method for stubbing
*/
public static Stubber doCallRealMethod() {
return MOCKITO_CORE.doAnswer(new CallsRealMethods());
}
/**
* Use doAnswer() when you want to stub a void method with generic {@link Answer}.
* <p>
* Stubbing voids requires different approach from {@link Mockito#when(Object)} because the compiler does not like void methods inside brackets...
* <p>
* Example:
*
* <pre>
* doAnswer(new Answer() {
* public Object answer(InvocationOnMock invocation) {
* Object[] args = invocation.getArguments();
* Mock mock = invocation.getMock();
* return null;
* }})
* .when(mock).someMethod();
* </pre>
* <p>
* See examples in javadoc for {@link Mockito} class
*
* @param answer to answer when the stubbed method is called
* @return stubber - to select a method for stubbing
*/
public static Stubber doAnswer(Answer answer) {
return MOCKITO_CORE.doAnswer(answer);
}
/**
* Use doNothing() for setting void methods to do nothing. <b>Beware that void methods on mocks do nothing by default!</b>
* However, there are rare situations when doNothing() comes handy:
* <p>
* 1. Stubbing consecutive calls on a void method:
* <pre>
* doNothing().
* doThrow(new RuntimeException())
* .when(mock).someVoidMethod();
*
* //does nothing the first time:
* mock.someVoidMethod();
*
* //throws RuntimeException the next time:
* mock.someVoidMethod();
* </pre>
*
* 2. When you spy real objects and you want the void method to do nothing:
* <pre>
* List list = new LinkedList();
* List spy = spy(list);
*
* //let's make clear() do nothing
* doNothing().when(spy).clear();
*
* spy.add("one");
*
* //clear() does nothing, so the list still contains "one"
* spy.clear();
* </pre>
* <p>
* See examples in javadoc for {@link Mockito} class
*
* @return stubber - to select a method for stubbing
*/
public static Stubber doNothing() {
return MOCKITO_CORE.doAnswer(new DoesNothing());
}
/**
* Use doReturn() in those rare occasions when you cannot use {@link Mockito#when(Object)}.
* <p>
* <b>Beware that {@link Mockito#when(Object)} is always recommended for stubbing because it is argument type-safe
* and more readable</b> (especially when stubbing consecutive calls).
* <p>
* Here are those rare occasions when doReturn() comes handy:
* <p>
*
* 1. When spying real objects and calling real methods on a spy brings side effects
*
* <pre>
* List list = new LinkedList();
* List spy = spy(list);
*
* //Impossible: real method is called so spy.get(0) throws IndexOutOfBoundsException (the list is yet empty)
* when(spy.get(0)).thenReturn("foo");
*
* //You have to use doReturn() for stubbing:
* doReturn("foo").when(spy).get(0);
* </pre>
*
* 2. Overriding a previous exception-stubbing:
*
* <pre>
* when(mock.foo()).thenThrow(new RuntimeException());
*
* //Impossible: the exception-stubbed foo() method is called so RuntimeException is thrown.
* when(mock.foo()).thenReturn("bar");
*
* //You have to use doReturn() for stubbing:
* doReturn("bar").when(mock).foo();
* </pre>
*
* Above scenarios shows a tradeoff of Mockito's ellegant syntax. Note that the scenarios are very rare, though.
* Spying should be sporadic and overriding exception-stubbing is very rare. Not to mention that in general
* overridding stubbing is a potential code smell that points out too much stubbing.
* <p>
* See examples in javadoc for {@link Mockito} class
*
* @param toBeReturned to be returned when the stubbed method is called
* @return stubber - to select a method for stubbing
*/
public static Stubber doReturn(Object toBeReturned) {
return MOCKITO_CORE.doAnswer(new Returns(toBeReturned));
}
/**
* Creates InOrder object that allows verifying mocks in order.
*
* <pre>
* InOrder inOrder = inOrder(firstMock, secondMock);
*
* inOrder.verify(firstMock).add("was called first");
* inOrder.verify(secondMock).add("was called second");
* </pre>
*
* Verification in order is flexible - <b>you don't have to verify all interactions</b> one-by-one
* but only those that you are interested in testing in order.
* <p>
* Also, you can create InOrder object passing only mocks that are relevant for in-order verification.
* <p>
* InOrder verification is 'greedy'. You will hardly every notice it but
* if you want to find out more search for 'greedy' on the Mockito
* <a href="http://code.google.com/p/mockito/w/list">wiki pages</a>.
* <p>
* As of Mockito 1.8.4 you can verifyNoMoreInvocations() in order-sensitive way. Read more: {@link InOrder#verifyNoMoreInteractions()}
* <p>
* See examples in javadoc for {@link Mockito} class
*
* @param mocks to be verified in order
*
* @return InOrder object to be used to verify in order
*/
public static InOrder inOrder(Object... mocks) {
return MOCKITO_CORE.inOrder(mocks);
}
/**
* Ignores stubbed methods of given mocks for the sake of verification.
* Sometimes useful when coupled with verifyNoMoreInteractions() or verification inOrder().
* Helps avoiding redundant verification of stubbed calls - typically we're not interested in verifying stubs.
* <p>
* <b>Warning</b>, ignoreStubs() might lead to overuse of verifyNoMoreInteractions(ignoreStubs(...));
* Bear in mind that Mockito does not recommend bombarding every test with verifyNoMoreInteractions()
* for the reasons outlined in javadoc for {@link Mockito#verifyNoMoreInteractions(Object...)}
* Other words: all *stubbed* methods of given mocks are marked *verfied* so that they don't get in a way during verifyNoMoreInteractions().
* <p>
* This method <b>changes the input mocks</b>! This method returns input mocks just for convenience.
* <p>
* Ignored stubs will also be ignored for verification inOrder, including {@link org.mockito.InOrder#verifyNoMoreInteractions()}.
* See the second example.
* <p>
* Example:
* <pre>
* //mocking lists for the sake of the example (if you mock List in real you will burn in hell)
* List mock1 = mock(List.class), mock2 = mock(List.class);
*
* //stubbing mocks:
* when(mock1.get(0)).thenReturn(10);
* when(mock2.get(0)).thenReturn(20);
*
* //using mocks by calling stubbed get(0) methods:
* System.out.println(mock1.get(0)); //prints 10
* System.out.println(mock2.get(0)); //prints 20
*
* //using mocks by calling clear() methods:
* mock1.clear();
* mock2.clear();
*
* //verification:
* verify(mock1).clear();
* verify(mock2).clear();
*
* //verifyNoMoreInteractions() fails because get() methods were not accounted for.
* try { verifyNoMoreInteractions(mock1, mock2); } catch (NoInteractionsWanted e);
*
* //However, if we ignore stubbed methods then we can verifyNoMoreInteractions()
* verifyNoMoreInteractions(ignoreStubs(mock1, mock2));
*
* //Remember that ignoreStubs() *changes* the input mocks and returns them for convenience.
* <pre>
* Ignoring stubs can be used with <b>verification in order</b>:
* <pre>
* List list = mock(List.class);
* when(mock.get(0)).thenReturn("foo");
*
* list.add(0);
* System.out.println(list.get(0)); //we don't want to verify this
* list.clear();
*
* InOrder inOrder = inOrder(ignoreStubs(list));
* inOrder.verify(list).add(0);
* inOrder.verify(list).clear();
* inOrder.verifyNoMoreInteractions();
* </pre>
*
* @since 1.9
* @param mocks input mocks that will be changed
* @return the same mocks that were passed in as parameters
*/
public static Object[] ignoreStubs(Object... mocks) {
return MOCKITO_CORE.ignoreStubs(mocks);
}
/**
* Allows verifying exact number of invocations. E.g:
* <pre>
* verify(mock, times(2)).someMethod("some arg");
* </pre>
*
* See examples in javadoc for {@link Mockito} class
*
* @param wantedNumberOfInvocations wanted number of invocations
*
* @return verification mode
*/
public static VerificationMode times(int wantedNumberOfInvocations) {
return VerificationModeFactory.times(wantedNumberOfInvocations);
}
/**
* Alias to times(0), see {@link Mockito#times(int)}
* <p>
* Verifies that interaction did not happen. E.g:
* <pre>
* verify(mock, never()).someMethod();
* </pre>
*
* <p>
* If you want to verify there were NO interactions with the mock
* check out {@link Mockito#verifyZeroInteractions(Object...)}
* or {@link Mockito#verifyNoMoreInteractions(Object...)}
* <p>
* See examples in javadoc for {@link Mockito} class
*
* @return verification mode
*/
public static VerificationMode never() {
return times(0);
}
/**
* Allows at-least-once verification. E.g:
* <pre>
* verify(mock, atLeastOnce()).someMethod("some arg");
* </pre>
* Alias to atLeast(1)
* <p>
* See examples in javadoc for {@link Mockito} class
*
* @return verification mode
*/
public static VerificationMode atLeastOnce() {
return VerificationModeFactory.atLeastOnce();
}
/**
* Allows at-least-x verification. E.g:
* <pre>
* verify(mock, atLeast(3)).someMethod("some arg");
* </pre>
*
* See examples in javadoc for {@link Mockito} class
*
* @param minNumberOfInvocations minimum number of invocations
*
* @return verification mode
*/
public static VerificationMode atLeast(int minNumberOfInvocations) {
return VerificationModeFactory.atLeast(minNumberOfInvocations);
}
/**
* Allows at-most-x verification. E.g:
* <pre>
* verify(mock, atMost(3)).someMethod("some arg");
* </pre>
*
* See examples in javadoc for {@link Mockito} class
*
* @param maxNumberOfInvocations max number of invocations
*
* @return verification mode
*/
public static VerificationMode atMost(int maxNumberOfInvocations) {
return VerificationModeFactory.atMost(maxNumberOfInvocations);
}
/**
* Allows checking if given method was the only one invoked. E.g:
* <pre>
* verify(mock, only()).someMethod();
* //above is a shorthand for following 2 lines of code:
* verify(mock).someMethod();
* verifyNoMoreInvocations(mock);
* </pre>
*
* <p>
* See also {@link Mockito#verifyNoMoreInteractions(Object...)}
* <p>
* See examples in javadoc for {@link Mockito} class
*
* @return verification mode
*/
//TODO make exception message nicer
public static VerificationMode only() {
return VerificationModeFactory.only();
}
/**
* Allows verifying with timeout. May be useful for testing in concurrent conditions.
* <p>
* It feels this feature should be used rarely - figure out a better way of testing your multi-threaded system
* <p>
* Not yet implemented to work with InOrder verification.
* <pre>
* //passes when someMethod() is called within given time span
* verify(mock, timeout(100)).someMethod();
* //above is an alias to:
* verify(mock, timeout(100).times(1)).someMethod();
*
* //passes when someMethod() is called *exactly* 2 times within given time span
* verify(mock, timeout(100).times(2)).someMethod();
*
* //passes when someMethod() is called *at lest* 2 times within given time span
* verify(mock, timeout(100).atLeast(2)).someMethod();
*
* //verifies someMethod() within given time span using given verification mode
* //useful only if you have your own custom verification modes.
* verify(mock, new Timeout(100, yourOwnVerificationMode)).someMethod();
* </pre>
*
* See examples in javadoc for {@link Mockito} class
*
* @param millis - time span in millis
*
* @return verification mode
*/
public static VerificationWithTimeout timeout(int millis) {
return new Timeout(millis, VerificationModeFactory.times(1));
}
/**
* First of all, in case of any trouble, I encourage you to read the Mockito FAQ: <a href="http://code.google.com/p/mockito/wiki/FAQ">http://code.google.com/p/mockito/wiki/FAQ</a>
* <p>
* In case of questions you may also post to mockito mailing list: <a href="http://groups.google.com/group/mockito">http://groups.google.com/group/mockito</a>
* <p>
* validateMockitoUsage() <b>explicitly validates</b> the framework state to detect invalid use of Mockito.
* However, this feature is optional <b>because Mockito validates the usage all the time...</b> but there is a gotcha so read on.
* <p>
* Examples of incorrect use:
* <pre>
* //Oups, someone forgot thenReturn() part:
* when(mock.get());
*
* //Oups, someone put the verified method call inside verify() where it should be outside:
* verify(mock.execute());
*
* //Oups, someone has used EasyMock for too long and forgot to specify the method to verify:
* verify(mock);
* </pre>
*
* Mockito throws exceptions if you misuse it so that you know if your tests are written correctly.
* The gotcha is that Mockito does the validation <b>next time</b> you use the framework (e.g. next time you verify, stub, call mock etc.).
* But even though the exception might be thrown in the next test,
* the exception <b>message contains a navigable stack trace element</b> with location of the defect.
* Hence you can click and find the place where Mockito was misused.
* <p>
* Sometimes though, you might want to validate the framework usage explicitly.
* For example, one of the users wanted to put validateMockitoUsage() in his @After method
* so that he knows immediately when he misused Mockito.
* Without it, he would have known about it not sooner than <b>next time</b> he used the framework.
* One more benefit of having validateMockitoUsage() in @After is that jUnit runner will always fail in the test method with defect
* whereas ordinary 'next-time' validation might fail the <b>next</b> test method.
* But even though JUnit might report next test as red, don't worry about it
* and just click at navigable stack trace element in the exception message to instantly locate the place where you misused mockito.
* <p>
* <b>Built-in runner: {@link MockitoJUnitRunner}</b> does validateMockitoUsage() after each test method.
* <p>
* Bear in mind that <b>usually you don't have to validateMockitoUsage()</b>
* and framework validation triggered on next-time basis should be just enough,
* mainly because of enhanced exception message with clickable location of defect.
* However, I would recommend validateMockitoUsage() if you already have sufficient test infrastructure
* (like your own runner or base class for all tests) because adding a special action to @After has zero cost.
* <p>
* See examples in javadoc for {@link Mockito} class
*/
public static void validateMockitoUsage() {
MOCKITO_CORE.validateMockitoUsage();
}
/**
* Allows mock creation with additional mock settings.
* <p>
* Don't use it too often.
* Consider writing simple tests that use simple mocks.
* Repeat after me: simple tests push simple, KISSy, readable & maintainable code.
* If you cannot write a test in a simple way - refactor the code under test.
* <p>
* Examples of mock settings:
* <pre>
* //Creates mock with different default answer & name
* Foo mock = mock(Foo.class, withSettings()
* .defaultAnswer(RETURNS_SMART_NULLS)
* .name("cool mockie"));
*
* //Creates mock with different default answer, descriptive name and extra interfaces
* Foo mock = mock(Foo.class, withSettings()
* .defaultAnswer(RETURNS_SMART_NULLS)
* .name("cool mockie")
* .extraInterfaces(Bar.class));
* </pre>
* {@link MockSettings} has been introduced for two reasons.
* Firstly, to make it easy to add another mock settings when the demand comes.
* Secondly, to enable combining different mock settings without introducing zillions of overloaded mock() methods.
* <p>
* See javadoc for {@link MockSettings} to learn about possible mock settings.
* <p>
*
* @return mock settings instance with defaults.
*/
public static MockSettings withSettings() {
return new MockSettingsImpl().defaultAnswer(RETURNS_DEFAULTS);
}
/*
* Helps debugging failing tests. Experimental - use at your own risk. We're not sure if this method will stay in public api.
*/
@Deprecated
static MockitoDebugger debug() {
return new MockitoDebuggerImpl();
}
}