/*
* Copyright (C) 2011 The Guava Authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.common.base;
import static com.google.common.truth.Truth.assertThat;
import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.GwtIncompatible;
import com.google.common.collect.FluentIterable;
import com.google.common.collect.ImmutableList;
import com.google.common.testing.NullPointerTester;
import com.google.common.testing.SerializableTester;
import junit.framework.TestCase;
import java.util.Collections;
import java.util.List;
import java.util.Set;
/**
* Unit test for {@link Optional}.
*
* @author Kurt Alfred Kluever
*/
@GwtCompatible(emulated = true)
public final class OptionalTest extends TestCase {
public void testAbsent() {
Optional<String> optionalName = Optional.absent();
assertFalse(optionalName.isPresent());
}
public void testOf() {
assertEquals("training", Optional.of("training").get());
}
public void testOf_null() {
try {
Optional.of(null);
fail();
} catch (NullPointerException expected) {
}
}
public void testFromNullable() {
Optional<String> optionalName = Optional.fromNullable("bob");
assertEquals("bob", optionalName.get());
}
public void testFromNullable_null() {
// not promised by spec, but easier to test
assertSame(Optional.absent(), Optional.fromNullable(null));
}
public void testIsPresent_no() {
assertFalse(Optional.absent().isPresent());
}
public void testIsPresent_yes() {
assertTrue(Optional.of("training").isPresent());
}
public void testGet_absent() {
Optional<String> optional = Optional.absent();
try {
optional.get();
fail();
} catch (IllegalStateException expected) {
}
}
public void testGet_present() {
assertEquals("training", Optional.of("training").get());
}
public void testOr_T_present() {
assertEquals("a", Optional.of("a").or("default"));
}
public void testOr_T_absent() {
assertEquals("default", Optional.absent().or("default"));
}
public void testOr_supplier_present() {
assertEquals("a", Optional.of("a").or(Suppliers.ofInstance("fallback")));
}
public void testOr_supplier_absent() {
assertEquals("fallback", Optional.absent().or(Suppliers.ofInstance("fallback")));
}
public void testOr_nullSupplier_absent() {
Supplier<Object> nullSupplier = Suppliers.ofInstance(null);
Optional<Object> absentOptional = Optional.absent();
try {
absentOptional.or(nullSupplier);
fail();
} catch (NullPointerException expected) {
}
}
public void testOr_nullSupplier_present() {
Supplier<String> nullSupplier = Suppliers.ofInstance(null);
assertEquals("a", Optional.of("a").or(nullSupplier));
}
public void testOr_Optional_present() {
assertEquals(Optional.of("a"), Optional.of("a").or(Optional.of("fallback")));
}
public void testOr_Optional_absent() {
assertEquals(Optional.of("fallback"), Optional.absent().or(Optional.of("fallback")));
}
public void testOrNull_present() {
assertEquals("a", Optional.of("a").orNull());
}
public void testOrNull_absent() {
assertNull(Optional.absent().orNull());
}
public void testAsSet_present() {
Set<String> expected = Collections.singleton("a");
assertEquals(expected, Optional.of("a").asSet());
}
public void testAsSet_absent() {
assertTrue("Returned set should be empty", Optional.absent().asSet().isEmpty());
}
public void testAsSet_presentIsImmutable() {
Set<String> presentAsSet = Optional.of("a").asSet();
try {
presentAsSet.add("b");
fail();
} catch (UnsupportedOperationException expected) {
}
}
public void testAsSet_absentIsImmutable() {
Set<Object> absentAsSet = Optional.absent().asSet();
try {
absentAsSet.add("foo");
fail();
} catch (UnsupportedOperationException expected) {
}
}
public void testTransform_absent() {
assertEquals(Optional.absent(), Optional.absent().transform(Functions.identity()));
assertEquals(Optional.absent(), Optional.absent().transform(Functions.toStringFunction()));
}
public void testTransform_presentIdentity() {
assertEquals(Optional.of("a"), Optional.of("a").transform(Functions.identity()));
}
public void testTransform_presentToString() {
assertEquals(Optional.of("42"), Optional.of(42).transform(Functions.toStringFunction()));
}
public void testTransform_present_functionReturnsNull() {
try {
Optional.of("a").transform(
new Function<String, String>() {
@Override public String apply(String input) {
return null;
}
});
fail("Should throw if Function returns null.");
} catch (NullPointerException expected) {
}
}
public void testTransform_abssent_functionReturnsNull() {
assertEquals(Optional.absent(),
Optional.absent().transform(
new Function<Object, Object>() {
@Override public Object apply(Object input) {
return null;
}
}));
}
// TODO(kevinb): use EqualsTester
public void testEqualsAndHashCode_absent() {
assertEquals(Optional.<String>absent(), Optional.<Integer>absent());
assertEquals(Optional.absent().hashCode(), Optional.absent().hashCode());
}
public void testEqualsAndHashCode_present() {
assertEquals(Optional.of("training"), Optional.of("training"));
assertFalse(Optional.of("a").equals(Optional.of("b")));
assertFalse(Optional.of("a").equals(Optional.absent()));
assertEquals(Optional.of("training").hashCode(), Optional.of("training").hashCode());
}
public void testToString_absent() {
assertEquals("Optional.absent()", Optional.absent().toString());
}
public void testToString_present() {
assertEquals("Optional.of(training)", Optional.of("training").toString());
}
public void testPresentInstances_allPresent() {
List<Optional<String>> optionals =
ImmutableList.of(Optional.of("a"), Optional.of("b"), Optional.of("c"));
assertThat(Optional.presentInstances(optionals)).iteratesAs("a", "b", "c");
}
public void testPresentInstances_allAbsent() {
List<Optional<Object>> optionals =
ImmutableList.of(Optional.absent(), Optional.absent());
assertThat(Optional.presentInstances(optionals)).isEmpty();
}
public void testPresentInstances_somePresent() {
List<Optional<String>> optionals =
ImmutableList.of(Optional.of("a"), Optional.<String>absent(), Optional.of("c"));
assertThat(Optional.presentInstances(optionals)).iteratesAs("a", "c");
}
public void testPresentInstances_callingIteratorTwice() {
List<Optional<String>> optionals =
ImmutableList.of(Optional.of("a"), Optional.<String>absent(), Optional.of("c"));
Iterable<String> onlyPresent = Optional.presentInstances(optionals);
assertThat(onlyPresent).iteratesAs("a", "c");
assertThat(onlyPresent).iteratesAs("a", "c");
}
public void testPresentInstances_wildcards() {
List<Optional<? extends Number>> optionals =
ImmutableList.<Optional<? extends Number>>of(Optional.<Double>absent(), Optional.of(2));
Iterable<Number> onlyPresent = Optional.presentInstances(optionals);
assertThat(onlyPresent).iteratesAs(2);
}
private static Optional<Integer> getSomeOptionalInt() {
return Optional.of(1);
}
private static FluentIterable<? extends Number> getSomeNumbers() {
return FluentIterable.from(ImmutableList.<Number>of());
}
/*
* The following tests demonstrate the shortcomings of or() and test that the casting workaround
* mentioned in the method Javadoc does in fact compile.
*/
@SuppressWarnings("unused") // compilation test
public void testSampleCodeError1() {
Optional<Integer> optionalInt = getSomeOptionalInt();
// Number value = optionalInt.or(0.5); // error
}
@SuppressWarnings("unused") // compilation test
public void testSampleCodeError2() {
FluentIterable<? extends Number> numbers = getSomeNumbers();
Optional<? extends Number> first = numbers.first();
// Number value = first.or(0.5); // error
}
@SuppressWarnings("unused") // compilation test
public void testSampleCodeFine1() {
Optional<Number> optionalInt = Optional.of((Number) 1);
Number value = optionalInt.or(0.5); // fine
}
@SuppressWarnings("unused") // compilation test
public void testSampleCodeFine2() {
FluentIterable<? extends Number> numbers = getSomeNumbers();
// Sadly, the following is what users will have to do in some circumstances.
@SuppressWarnings("unchecked") // safe covariant cast
Optional<Number> first = (Optional) numbers.first();
Number value = first.or(0.5); // fine
}
@GwtIncompatible("SerializableTester")
public void testSerialization() {
SerializableTester.reserializeAndAssert(Optional.absent());
SerializableTester.reserializeAndAssert(Optional.of("foo"));
}
@GwtIncompatible("NullPointerTester")
public void testNullPointers() {
NullPointerTester npTester = new NullPointerTester();
npTester.testAllPublicConstructors(Optional.class);
npTester.testAllPublicStaticMethods(Optional.class);
npTester.testAllPublicInstanceMethods(Optional.absent());
npTester.testAllPublicInstanceMethods(Optional.of("training"));
}
}