@nested example

nested-example.java

class TestableClass {
  public foo() { /* do something */ }
  
  public bar() { /* do something */ }
}

class TestableClassTest {
  // test suite for Foo
  @Nested
  class Foo {
    @Test
    void shouldDoA() { }
    
    @Test
    void shouldDoB() { }
  }
  
  // test suite for Bar
  @Nested
  class Bar{
    @Test
    void shouldDoA() { }
    
    @Test
    void shouldDoB() { }
  }
}