Using Mockito

Using Mockito

• 1.
  Using Mockito
• 2.
  This work by FredrikWendt is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License http://creativecommons.org/licenses/by-nc-sa/3.0/
• 3.
  Outline • mock(ClassToMock.class) • when(methodCall) ●thenReturn(value) ● thenThrow(Throwable) • verify(mock).method(args) • @Mock • initMocks(this) • assertThat(obj, matcher) • Eclipse IDE tips
• 4.
  Why Mockito -and when? Use Mockito to get ”smart” fake implementations of classes or interfaces out of your reach.
• 5.
  Classical 3A Test @Test publicvoid test() throws Exception { // Arrange // Act // Assert }
• 6.
  Classical 3A Test @Test publicvoid test() throws Exception { // Arrange UnitToTest testee = new UnitToTest(); Helper helper = new Helper(); // Act testee.doSomething(helper); // Assert assertTrue(helper.somethingHappened()); }
• 7.
  Mockito ”Template” Usage @Test publicvoid test() throws Exception { // Arrange, prepare behaviour Helper aMock = mock(Helper.class); when(aMock.isCalled()).thenReturn(true); // Act testee.doSomething(aMock); // Assert - verify interactions verify(aMock).isCalled(); }
• 8.
  when(...).then*(...) when(methodIsCalled).thenReturn(aValue); when(methodIsCalled).thenThrow(anException);
• 9.
  Real Code Properties properties= mock(Properties.class); when(properties.get(”shoeSize”)).thenReturn(”42”); String result = properties.get(”shoeSize”); assertEquals(”42”, result);
• 10.
  Real Code Properties properties= mock(Properties.class); when(properties.get(”shoeSize”)).thenReturn(”42”); String result = properties.get(”shoeSize”); assertEquals(”42”, result); // optional verify(properties).get(”shoeSize”);
• 11.
  when(...) when(methodIsCalled) aMockObject.method(arguments...) properties.get(”42”) properties.get(anyString()) properties.get(eq(”42”))
• 12.
  thenReturn(value) Properties properties =mock(Properties.class); when(properties.get(”shoeSize”)) .thenReturn(”42”)); String value = properties.get(”shoeSize”); assertEquals(”42”, value);
• 13.
  thenThrow(Exception) Properties properties =mock(Properties.class); when(properties.get(”shoooSize”)) .thenThrow(new IllegalArgumentException(...)); try { properties.get(”shoooSize”); fail(”shoooSize is misspelled”); } catch (IllegalArgumentException e) { // good! :) }
• 14.
  thenReturn(...) Properties properties =mock(Properties.class); when(properties.get(”shoeSize”)) .thenReturn(”42”, ”43”, ”44”)); assertEquals(”42”, properties.get(”shoeSize”)); assertEquals(”43”, properties.get(”shoeSize”)); assertEquals(”44”, properties.get(”shoeSize”)); assertEquals(”44”, properties.get(”shoeSize”)); assertEquals(”44”, properties.get(”shoeSize”)); assertEquals(”44”, properties.get(”shoeSize”));
• 15.
  Creating Mock Objects ClassToMockmockObject = mock(ClassToMock.class); egentligen: Mockito.mock(ClassToMock.class);
• 16.
  Creating Mock Objects ClassToMockmockObject = mock(ClassToMock.class); @Mock ClassToMock mockObject; @Before public void setup() { MockitoAnnotations.initMocks(this); }
• 17.
  Verifying Invocation OnMocks // simple ”equals” verify(properties).get(”property”); // matchers verify(properties).get(eq(”property”));
• 18.
  The IDE CanHelp 1 • Window » Preferences » Java » Editor » Content Assistant » Favorites ● org.junit.Assert.* assertTrue() ● org.mockito.Mockito.* mock() ● org.mockito.MockitoAnnotations @Mock ● org.mockito.BDDMockito.* given().then*()
• 19.
  The IDE CanHelp 2 • Window » Preferences » Java » Editor » Templates ${staticImport:importStatic( 'org.mockito.MockitoAnnotations. initMocks')} @${beforeAnnotation: newType(org.junit.Before)} public void ${setUp}() { initMocks(this); ${cursor} }
• 20.
  The IDE CanHelp 3 • Window » Preferences » Java » Editor » Templates tdd @Test public void ${test} throws Exception { // Arrange // Act // Assert }
• 21.
  public class EmptyMatcherextends TypeSafeMatcher<Collection <?>> { @Override public boolean matchesSafely(Collection<?> c) { return c.isEmpty(); } public void describeTo(Description desc) { desc.appendText("empty"); } @Factory public static <T> Matcher<? super Collection<?>> isEmpty() { return new EmptyMatcher(); } }