How to test a method of a class with constructor arguments using Mockito/Powermock
I have a Mockito/PowerMockito issue!
The class to test is as below :
public class ClassToTest { private String string; public ClassToTest(String s) { this.string = s; } public String concatenate() { return string.concat(" - Done!"); } public ClassToTest create(String s) { return new ClassToTest(s); } } The test class i wrote :
import org.junit.Test; import org.junit.runner.RunWith; import org.mockito.Mockito; import org.powermock.api.mockito.PowerMockito; import org.powermock.core.classloader.annotations.PrepareForTest; import org.powermock.modules.junit4.PowerMockRunner; @RunWith(PowerMockRunner.class) @PrepareForTest(ClassToTest.class) public class ClassToTestTest { @Test public void concatenate() throws Exception { ClassToTest classToTest = Mockito.mock(ClassToTest.class); PowerMockito.whenNew(ClassToTest.class).withArguments(Mockito.anyString()).thenReturn(classToTest); classToTest.concatenate(); } } Question – How do i set a value of the instance variable named "string" from test class so that i can test concatenate method(concatenate method uses the constructor initialized "string" variable") Currently the debug point is not even going inside concatenate() method. I need to do this with either mockito/powermock.
Note – The example I have given is a representation of the issue i am facing in real time.
Any leads would help me.
Thanks in advance!!
Your test is pointless for several reasons.
- you mock the class you’re trying to test
- you mock a method that is not even called in the test
- you don’t verify the result of the method you call.
Your test can just be
ClassToTest tested = new ClassToTest("test"); // create instance String concatResult = tested.concatenate(); // call method under test assertThat(concatResult).isEqualTo("test - Done"); // verify result No need to mock anything. If you want to test the create method (of which I don’t see the point at all btw), you can do
ClassToTest tested = new ClassToTest(""); // the String is never used anyway ClassToTest created = tested.create("test"); // call method under test assertThat(created.concatenate()).isEqualTo("test - Done"); // verify If you mock classes you’re testing, you don’t test the classes behavior, but only the mocked result. Consider
Don’t do this
ClassToTest mock = mock(ClassToTest.class); ClassToTest other = mock(ClassToTest.class); when(mock.create(anyString()).thenReturn(other); when(other.concatenate(anyString()).thenReturn("expected"); ClassToTest created = mock.create("test"); String result = created.concatenate("lala"); assertThat(result).isEqualTo("expected"); // duh 
