JMockIt Tutorial Translation - Mocking Supporting tagline

// "Dependency" is mocked for all tests in this test class.
// The "mockInstance" field holds a mocked instance automatically created for use in each test.
@Mocked Dependency mockInstance;

@Test
public void doBusinessOperationXyz(@Mocked final AnotherDependency anotherMock)
{
   ...
   new Expectations() {{ // an "expectation block"
      ...
      // Record an expectation, with a given value to be returned:
      mockInstance.mockedMethod(...); result = 123;
      ...
   }};
   ...
   // Call the code under test.
   ...
   new Verifications() {{ // a "verification block"
      // Verifies an expected invocation:
      anotherMock.save(any); times = 1;
   }};
   ...
}

@Test
public void doBusinessOperationXyz(@Mocked final Dependency mockInstance)
{
   ...
   new Expectations() {{
      ...
      // An expectation for an instance method:
      mockInstance.someMethod(1, "test"); result = "mocked";
      ...
   }};

   // A call to code under test occurs here, leading to mock invocations
   // that may or may not match specified expectations.
}

@Test
public void someTestMethod()
{
   // 1. Preparation: whatever is required before the code under test can be exercised.
   ...
   // 2. The code under test is exercised, usually by calling a public method.
   ...
   // 3. Verification: whatever needs to be checked to make sure the code exercised by
   //    the test did its job.
   ...
}

import mockit.*;
... other imports ...

public class SomeTest
{
   // Zero or more "mock fields" common to all test methods in the class:
   @Mocked Collaborator mockCollaborator;
   @Mocked AnotherDependency anotherDependency;
   ...

   @Test
   public void testWithRecordAndReplayOnly(mock parameters)
   {
      // Preparation code not specific to JMockit, if any.

      new Expectations() {{ // an "expectation block"
         // One or more invocations to mocked types, causing expectations to be recorded.
         // Invocations to non-mocked types are also allowed anywhere inside this block
         // (though not recommended).
      }};

      // Unit under test is exercised.

      // Verification code (JUnit/TestNG assertions), if any.
   }

   @Test
   public void testWithReplayAndVerifyOnly(mock parameters)
   {
      // Preparation code not specific to JMockit, if any.

      // Unit under test is exercised.

      new Verifications() {{ // a "verification block"
         // One or more invocations to mocked types, causing expectations to be verified.
         // Invocations to non-mocked types are also allowed anywhere inside this block
         // (though not recommended).
      }};

      // Additional verification code, if any, either here or before the verification block.
   }

   @Test
   public void testWithBothRecordAndVerify(mock parameters)
   {
      // Preparation code not specific to JMockit, if any.

      new Expectations() {{
         // One or more invocations to mocked types, causing expectations to be recorded.
      }};

      // Unit under test is exercised.

      new VerificationsInOrder() {{ // an ordered verification block
         // One or more invocations to mocked types, causing expectations to be verified
         // in the specified order.
      }};

      // Additional verification code, if any, either here or before the verification block.
   }
}

public class UnitUnderTest
{
(1)private final DependencyAbc abc = new DependencyAbc();

   public void doSomething()
   {
(2)   int n = abc.intReturningMethod();

      for (int i = 0; i < n; i++) {
         String s;

         try {
(3)         s = abc.stringReturningMethod();
         }
         catch (SomeCheckedException e) {
            // somehow handle the exception
         }

         // do some other stuff
      }
   }
}

@Test
public void doSomethingHandlesSomeCheckedException(@Mocked final DependencyAbc abc) throws Exception
{
   new Expectations() {{
(1)   new DependencyAbc();

(2)   abc.intReturningMethod(); result = 3;

(3)   abc.stringReturningMethod();
      returns("str1", "str2");
      result = new SomeCheckedException();
   }};

   new UnitUnderTest().doSomething();
}

public final class ConcatenatingInputStream extends InputStream
{
   private final Queue<InputStream> sequentialInputs;
   private InputStream currentInput;

   public ConcatenatingInputStream(InputStream... sequentialInputs)
   {
      this.sequentialInputs = new LinkedList<InputStream>(Arrays.asList(sequentialInputs));
      currentInput = this.sequentialInputs.poll();
   }

   @Override
   public int read() throws IOException
   {
      if (currentInput == null) return -1;

      int nextByte = currentInput.read();

      if (nextByte >= 0) {
         return nextByte;
      }

      currentInput = sequentialInputs.poll();
      return read();
   }
}

@Test
public void concatenateInputStreams(
   @Injectable final InputStream input1, @Injectable final InputStream input2)
   throws Exception
{
   new Expectations() {{
      input1.read(); returns(1, 2, -1);
      input2.read(); returns(3, -1);
   }};

   InputStream concatenatedInput = new ConcatenatingInputStream(input1, input2);
   byte[] buf = new byte[3];
   concatenatedInput.read(buf);

   assertArrayEquals(new byte[] {1, 2, 3}, buf);
}

@Test
public void matchOnMockInstance(@Mocked final Collaborator mock)
{
   new Expectations() {{
      onInstance(mock).getValue(); result = 12;
   }};

   // Exercise code under test with mocked instance passed from the test:
   int result = mock.getValue();
   assertEquals(12, result);

   // If another instance is created inside code under test...
   Collaborator another = new Collaborator();

   // ...we won't get the recorded result, but the default one:
   assertEquals(0, another.getValue());
}

@Test
public void newCollaboratorsWithDifferentBehaviors(@Mocked Collaborator anyCollaborator)
{
   // Record different behaviors for each set of instances:
   new Expectations() {{
      // One set, instances created with "a value":
      Collaborator col1 = new Collaborator("a value");
      col1.doSomething(anyInt); result = 123;

      // Another set, instances created with "another value":
      Collaborator col2 = new Collaborator("another value");
      col2.doSomething(anyInt); result = new InvalidStateException();
   }};

   // Code under test:
   new Collaborator("a value").doSomething(5); // will return 123
   ...
   new Collaborator("another value").doSomething(0); // will throw the exception
   ...
}

@Test
public void newCollaboratorsWithDifferentBehaviors(
   @Mocked final Collaborator col1, @Mocked final Collaborator col2)
{
   new Expectations() {{
      // Map separate sets of future instances to separate mock parameters:
      new Collaborator("a value"); result = col1;
      new Collaborator("another value"); result = col2;

      // Record different behaviors for each set of instances:
      col1.doSomething(anyInt); result = 123;
      col2.doSomething(anyInt); result = new InvalidStateException();
   }};

   // Code under test:
   new Collaborator("a value").doSomething(5); // will return 123
   ...
   new Collaborator("another value").doSomething(0); // will throw the exception
   ...
}

@Test
public void someTestMethod(@Mocked final DependencyAbc abc)
{
   final DataItem item = new DataItem(...);

   new Expectations() {{
      // Will match "voidMethod(String, List)" invocations where the first argument is
      // any string and the second any list.
      abc.voidMethod(anyString, (List<?>) any);
   }};

   new UnitUnderTest().doSomething(item);

   new Verifications() {{
      // Matches invocations to the specified method with any value of type long or Long.
      abc.anotherVoidMethod(anyLong);
   }};
}

@Test
public void someTestMethod(@Mocked final DependencyAbc abc)
{
   final DataItem item = new DataItem(...);

   new Expectations() {{
      // Will match "voidMethod(String, List)" invocations with the first argument
      // equal to "str" and the second not null.
      abc.voidMethod("str", (List<?>) withNotNull());

      // Will match invocations to DependencyAbc#stringReturningMethod(DataItem, String)
      // with the first argument pointing to "item" and the second one containing "xyz".
      abc.stringReturningMethod(withSameInstance(item), withSubstring("xyz"));
   }};

   new UnitUnderTest().doSomething(item);

   new Verifications() {{
      // Matches invocations to the specified method with any long-valued argument.
      abc.anotherVoidMethod(withAny(1L));
   }};
}

@Test
public void someTestMethod(@Mocked final DependencyAbc abc)
{
   ...
   new Expectations() {{
      abc.voidMethod(anyString, null);
   }};
   ...
}

@Test
public void someTestMethod(@Mocked final DependencyAbc abc)
{
   new Expectations() {{
      // By default, at least one invocation is expected, i.e. "minTimes = 1":
      new DependencyAbc();

      // At least two invocations are expected:
      abc.voidMethod(); minTimes = 2;

      // 1 to 5 invocations are expected:
      abc.stringReturningMethod(); minTimes = 1; maxTimes = 5;
   }};

   new UnitUnderTest().doSomething();
}

@Test
public void someOtherTestMethod(@Mocked final DependencyAbc abc)
{
   new UnitUnderTest().doSomething();

   new Verifications() {{
      // Verifies that zero or one invocations occurred, with the specified argument value:
      abc.anotherVoidMethod(3); maxTimes = 1;

      // Verifies the occurrence of at least one invocation with the specified arguments:
      DependencyAbc.someStaticMethod("test", false); // "minTimes = 1" is implied
   }};
}

@Test
public void verifyInvocationsExplicitlyAtEndOfTest(@Mocked final Dependency mock)
{
   // Nothing recorded here, though it could be.

   // Inside tested code:
   Dependency dependency = new Dependency();
   dependency.doSomething(123, true, "abc-xyz");

   // Verifies that Dependency#doSomething(int, boolean, String) was called at least once,
   // with arguments that obey the specified constraints:
   new Verifications() {{ mock.doSomething(anyInt, true, withPrefix("abc")); }};
}

@Test
public void verifyingExpectationsInOrder(@Mocked final DependencyAbc abc)
{
   // Somewhere inside the tested code:
   abc.aMethod();
   abc.doSomething("blah", 123);
   abc.anotherMethod(5);
   ...

   new VerificationsInOrder() {\{
      // The order of these invocations must be the same as the order
      // of occurrence during replay of the matching invocations.
      abc.aMethod();
      abc.anotherMethod(anyInt);
   }};
}