@Test public void stringNumbersCommaDelimitedReturnsSum() { assertEquals(3, this.stringCalculator.add("1,2")); }
public int add(String input) { if (input.isEmpty()) return 0; String delimiter = getDelimiter(input); String numbers = getNumbers(input); return calculateSum(numbers.split(delimiter)); }
StringCalculator { public int add(String input) { if (input.isEmpty()) return 0; String delimiter = getDelimiter(input); String numbers = getNumbers(input); return calculateSum(numbers.split(delimiter)); } }
StringCalculator { public int add(String input) { if (input.isEmpty()) return 0; String delimiter = getDelimiter(input); String numbers = getNumbers(input); return calculateSum(numbers.split(delimiter)); }  }
StringCalculator { public int add(String input) { if (input.isEmpty()) return 0; String delimiter = getDelimiter(input); String numbers = getNumbers(input); return calculateSum(numbers.split(delimiter)); }  int add(String input); }
StringCalculator { public int add(String input) { if (input.isEmpty()) return 0; String delimiter = getDelimiter(input); String numbers = getNumbers(input); return calculateSum(numbers.split(delimiter)); }  int add(String input);  }