source: class FlowTest {
  
      final TestKey able;
      final TestKey baker;
      final TestKey charlie;
      final TestKey delta;
      @Mock ServiceProvider serviceProvider;
      @Mock KeyManager keyManager;
       History lastStack;
       Direction lastDirection;
  
      @Test public void incorrectFlowGetUsage() {
  
target:         Context mockContext = Mockito.mock(Context.class);
          //noinspection WrongConstant
          Mockito.when(mockContext.getSystemService(Mockito.anyString())).thenReturn(null);
  
          try {
              Flow.get(mockContext);
  
              fail("Flow was supposed to throw an exception on wrong usage");
          } catch (IllegalStateException ignored) {
              // That's good!
          }
      }
  
  }