@EnumSource for enum values in JUnit - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of the @EnumSource annotation in JUnit?

@EnumSource is used to run a parameterized test with all or some values of an enum. It helps test methods with enum inputs easily.

beginner

How do you specify which enum to use with @EnumSource?

<p>You provide the enum class as a parameter, like <code>@EnumSource(MyEnum.class)</code>. This tells JUnit to use all values of <code>MyEnum</code> for the test.</p>

intermediate

How can you run a test with only specific enum values using @EnumSource?

Use the names attribute to list enum constants you want, e.g., @EnumSource(value = MyEnum.class, names = {"VALUE1", "VALUE2"}).

intermediate

What happens if you use @EnumSource without specifying an enum class?

<p>JUnit expects the parameter type of the test method to be an enum. It uses that enum class automatically.</p>

beginner

Write a simple example of a JUnit test method using @EnumSource to test all values of an enum Day.

enum Day { MONDAY, TUESDAY, WEDNESDAY }

@ParameterizedTest
@EnumSource(Day.class)
void testDayEnum(Day day) {
    assertNotNull(day);
}

What does @EnumSource(MyEnum.class) do in a JUnit test?

A Runs the test with all enum values except the first

B Runs the test once for each value in MyEnum

C Runs the test only once with the first enum value

D Runs the test with no enum values

@EnumSource(MyEnum.class) runs the test once for each enum constant in MyEnum.

How do you run a test with only specific enum values using @EnumSource?

A Use the <code>names</code> attribute with the enum constants you want

B Use <code>excludeNames</code> attribute

C Use <code>value</code> attribute with a list of values

D You cannot filter enum values with <code>@EnumSource</code>

The names attribute lets you specify which enum constants to include.

If the test method parameter type is an enum, can you omit the enum class in @EnumSource?

A Only if the enum is public

B No, you must always specify the enum class

C Yes, JUnit infers the enum class from the parameter type

D Only if the enum has less than 5 values

JUnit can infer the enum class from the test method parameter type if you omit it.

What type of test is @EnumSource mainly used with?

A Unit tests without parameters

B Performance tests

C Integration tests

D Parameterized tests

@EnumSource is designed for parameterized tests to supply enum values.

Which of these is a valid way to use @EnumSource?

A @EnumSource(value = Status.class, names = {"ACTIVE", "INACTIVE"})

B @EnumSource(Status.ACTIVE, Status.INACTIVE)

C @EnumSource(Status)

D @EnumSource(names = Status.class)

Option A correctly uses value and names attributes.

Explain how @EnumSource works in JUnit parameterized tests and how you can select specific enum values.

Think about how JUnit uses enum values to run tests multiple times.

Describe a simple example of a JUnit test method using @EnumSource with an enum parameter.

Imagine testing all days of the week using an enum.