使用FizzBuzz和JUnitParams进行单元测试

我有时使用FizzBuzz向新手演示单元测试的基础。尽管FizzBuzz确实是一个简单的问题，但它也可以用于演示更高级的单元测试技术，例如实现参数化测试。

FizzBuzz的可能解决方案之一是：

public class FizzBuzz {private static final int THREE = 3;private static final int FIVE = 5;public String calculate(int number) {if (isDivisibleBy(number, THREE) && isDivisibleBy(number, FIVE)) {return "FizzBuzz";}if (isDivisibleBy(number, THREE)) {return "Fizz";}if (isDivisibleBy(number, FIVE)) {return "Buzz";}return String.valueOf(number);}private boolean isDivisibleBy(int dividend, int divisor) {return dividend % divisor == 0;}
}

上面的示例非常适合显示JUnitParams的参数化测试。我们可以创建4种测试方法，每种方法用于不同的FizzBuzz案例：

@Test
@Parameters({"1", "2", "4", "7", "11", "13", "14"})
public void returnsNumberForNumberNotDivisibleByThreeAndFive(int number) {assertThat(fizzBuzz.calculate(number)).isEqualTo("" + number);
}@Test
@Parameters({"3", "6", "9", "12", "18", "21", "24"})
public void returnFizzForNumberDivisibleByThree(int number) {assertThat(fizzBuzz.calculate(number)).isEqualTo("Fizz");
}@Test
@Parameters({"5", "10", "20", "25", "35", "40", "50"})
public void returnBuzzForNumberDivisibleByFive(int number) {assertThat(fizzBuzz.calculate(number)).isEqualTo("Buzz");
}@Test
@Parameters({"15", "30", "45", "60"})
public void returnsFizzBuzzForNumberDivisibleByThreeAndFive(int number) {assertThat(fizzBuzz.calculate(number)).isEqualTo("FizzBuzz");
}

但是我们也可以用一种参数化的测试方法涵盖所有情况：

@Test
@Parameters
public void fizzBuzz(int given, String expected) {assertThat(fizzBuzz.calculate(given)).isEqualTo(expected);
}public Object[] parametersForFizzBuzz() {return $($(1, "1"),$(2, "2"),$(3, "Fizz"),$(4, "4"),$(5, "Buzz"),$(6, "Fizz"),$(7, "7"),$(10, "Buzz"),$(15, "FizzBuzz"),$(30, "FizzBuzz"));
}

享受JunitParams ！