doReturn and doThrow in JUnit - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to mock a method to return a value using doReturn.

JUnit

doReturn("mockedValue").when(mockedObject).[1]();

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AsomeMethod

BthrowException

CverifyCall

Dexecute

Attempts:

3 left

💡 Hint

Common Mistakes

Using a method name that does not exist in the mocked object.

Confusing doReturn with doThrow.

The method someMethod() is the one being mocked to return "mockedValue" using doReturn.

2fill in blank

medium

Complete the code to mock a method to throw an exception using doThrow.

JUnit

doThrow(new RuntimeException()).when(mockedObject).[1]();

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AsomeMethod

Brun

CexecuteAction

DthrowException

Attempts:

3 left

💡 Hint

Common Mistakes

Using doReturn instead of doThrow for exceptions.

Mocking a method that does not throw exceptions.

The method throwException() is mocked to throw a RuntimeException using doThrow.

3fill in blank

hard

Fix the error in the code to correctly mock a method to return a value using doReturn.

JUnit

doReturn("value").when([1]).someMethod();

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AmockedObject

BdoReturn

CsomeMethod

DRuntimeException

Attempts:

3 left

💡 Hint

Common Mistakes

Putting the method name inside when() instead of the mocked object.

Using exception classes instead of objects.

The when() method requires the mocked object, not a method or class name.

4fill in blank

hard

Fill both blanks to mock a method to throw an IllegalArgumentException.

JUnit

doThrow(new [1]()).when([2]).invalidMethod();

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AIllegalArgumentException

BmockedService

CRuntimeException

DmockedObject

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong exception class.

Confusing the mocked object variable name.

The exception type is IllegalArgumentException and the mocked object is mockedObject.

5fill in blank

hard

Fill all three blanks to mock a method to return "success" and verify it was called once.

JUnit

doReturn("[1]").when([2]).process();
verify([3], times(1)).process();

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Asuccess

BmockService

DmockedObject

Attempts:

3 left

💡 Hint

Common Mistakes

Using different variables for when() and verify().

Forgetting to match the return value string.

The method returns "success", and the mocked object is mockService used in both when() and verify().