How to write @Nested test classes in kotlin

Question

When writing a junit test:

internal class MyTest {
    @org.junit.jupiter.api.Nested
    class MyInnerClass {

    }
}

A warning is displayed by my code editor (IntelliJ)

Only non-static nested classes can serve as @Nested test classes.

How to write a nested classes in junit tests in kotlin?

Answer 1

When using @Nested classes in kotlin they need the prefix inner as only inner classes can be used as nested classes.

Only non-static nested classes (i.e. inner classes) can serve as @Nested test classes.

• https://junit.org/junit5/docs/current/user-guide/#writing-tests-nested

Your code should look somewhat like this:

internal class MyTest {
    @Nested
    inner class MyInnerClass {
        @Test
        fun customTest() {
           //TODO: do something
        }
    }
}