whenNew(LessSource.class).withArguments(input).thenReturn(lessSource);
when(output.lastModified()).thenReturn(1l);
when(lessSource.getLastModifiedIncludingImports()).thenReturn(2l);
doThrow(new LessException(new Throwable())).when(lessCompiler).compile(lessSource, output, false);
mojo.execute();
verify(buildContext).newScanner(same(sourceDirectory), eq(true));
verify(scanner).setIncludes(same(includes));