@Test
public void canCountNumbersOfLetters() throws Exception {
String string = "abcd abc";
WordCounter wc = new WordCounter(string);
assertEquals(2, wc.getCountOf('a'));
assertEquals(1, wc.getCountOf('d'));
assertEquals(0, wc.getCountOf('z'));
}
@Test
public void shouldWorkWithEmptyStrings() {
WordCounter wordCounter = new WordCounter("");
assertEquals(0, wordCounter.getCountOf('a'));
}