@NullAndEmptySource in JUnit - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to use @NullAndEmptySource in a JUnit 5 parameterized test.

JUnit

@ParameterizedTest
@[1]
void testWithNullAndEmpty(String input) {
    assertTrue(input == null || input.isEmpty());
}

Drag options to blanks, or click blank then click option'

ACsvSource

BValueSource

CMethodSource

DNullAndEmptySource

Attempts:

3 left

💡 Hint

Common Mistakes

Using @ValueSource instead, which does not provide null values.

Forgetting to annotate the method with @ParameterizedTest.

The @NullAndEmptySource annotation provides both null and empty string values to the parameterized test.

2fill in blank

medium

Complete the code to combine @NullAndEmptySource with @ValueSource to test multiple string inputs.

JUnit

@ParameterizedTest
@NullAndEmptySource
@[1](strings = {"test", "example"})
void testMultipleInputs(String input) {
    assertNotNull(input);
}

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ACsvSource

BMethodSource

CValueSource

DEnumSource

Attempts:

3 left

💡 Hint

Common Mistakes

Using @CsvSource which requires CSV formatted strings.

Using @EnumSource which is for enums, not strings.

The @ValueSource annotation is used to provide specific string values alongside null and empty from @NullAndEmptySource.

3fill in blank

hard

Fix the error in the code to correctly use @NullAndEmptySource with a parameterized test.

JUnit

@ParameterizedTest
@NullAndEmptySource
void testInput([1] input) {
    assertTrue(input == null || input.isEmpty());
}

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AString

Bboolean

CList<String>

Dint

Attempts:

3 left

💡 Hint

Common Mistakes

Using primitive types like int or boolean which cannot be null.

Using collection types which are not supported by @NullAndEmptySource.

The parameter type must be String because @NullAndEmptySource provides null and empty string values.

4fill in blank

hard

Fill both blanks to create a parameterized test that uses @NullAndEmptySource and asserts input is null or empty.

JUnit

@ParameterizedTest
@[1]
void testInputIsNullOrEmpty([2] input) {
    assertTrue(input == null || input.isEmpty());
}

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ANullAndEmptySource

BValueSource

CString

Dint

Attempts:

3 left

💡 Hint

Common Mistakes

Using int as parameter type which cannot be null.

Using @ValueSource annotation alone without @NullAndEmptySource.

Use @NullAndEmptySource annotation and String parameter type to test null and empty string inputs.

5fill in blank

hard

Fill all three blanks to write a parameterized test using @NullAndEmptySource and @ValueSource, asserting input is not null or empty for non-null values.

JUnit

@ParameterizedTest
@NullAndEmptySource
@[1](strings = {"hello", "world"})
void testNonNullInputs([2] input) {
    if (input != null) {
        assertFalse(input.[3]());
    }
}

Drag options to blanks, or click blank then click option'

AValueSource

BString

CisEmpty

DCsvSource

Attempts:

3 left

💡 Hint

Common Mistakes

Using CsvSource which requires CSV format.

Using int as parameter type which cannot be null.

Using wrong method name instead of isEmpty().

Use @ValueSource to provide string literals, String as parameter type, and isEmpty() method to check empty strings.