Example of Argument Captor

gistfile1.txt

public class MainClassTest {
    Utility utility = mock(Utility.class);
    @Test
    public void testCountofCharacter(){

        String testText = "Harvey : I don’t play the odds, I play the man.";

        MainClass mainClass = new MainClass(utility);
        mainClass.countNumberCharacter(testText, 'e');
        ArgumentCaptor<Integer> actualCount = ArgumentCaptor.forClass(Integer.class);
        verify(utility, times(1)).logToConsole(actualCount.capture());

        //Expected Number of 'e' in test text.
        //Harv'e'y : I don't play th'e' odds, I play th'e' man.
        Assert.assertEquals(3, (long)actualCount.getValue());
    }

}