Mockito / PowerMocktio doNothing for none void method

java unit-testing junit mockito powermock
Mat picture Mat · Jul 29, 2014 · Viewed 14.3k times · Source

I need a method which returns something to do nothing when invoked during testing, the class instance which owns the method is implemented as a spy.

I am aware the doNothing() method only works with void methods. Is there a way to get the same behaviour with a method that returns something?

Thank you!

Answer

John B picture John B · Jul 29, 2014

Use when(spy.myMethod()).thenReturn(null). This will prevent the spy from invoking the wrapped instance. You have to tell Mockito what to return for a method that returns something. The default behavior for a mock is to return null. The default behavior for a spy is to call the wrapped object. When you stub a method in a spy it prevents the call to the wrapped object and executes the specified behavior.

Per documents of Spy, you could also do doReturn(null).when(spy).myMethod();

Related questions

How to mock static method without powermock

Is there any way we can mock the static util method while testing in JUnit? I know Powermock can mock static calls, but I don't want to use Powermock. Are there any alternatives?

Read More
How to mock object with constructor that takes a Class?

This is the test: import static junit.framework.Assert.assertTrue; import static org.powermock.api.mockito.PowerMockito.mock; import static org.powermock.api.mockito.PowerMockito.whenNew; import org.junit.Test; import org.junit.runner.RunWith; import org.powermock.core.classloader.…

Read More
Mocking static methods with PowerMock and Mockito

I'm trying to verify a call to java.sql.DriverManager.getConnection using JUnit, Mockito, and PowerMock. Here's my test case: @RunWith(PowerMockRunner.class) @PrepareForTest(DriverManager.class) public class MySQLDatabaseConnectionFactoryTest { private ConfigurationService configurationService; private MySQLDatabaseConnectionFactory reference; @Before public void setUp() throws …

Read More