Learning Test-Driven Development with Go/

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FizzBuzz: Not-Divisible Requirement

FizzBuzz: Not-Divisible Requirement

Add test scenarios to our FizzBuzz kata to better understand how to apply TDD.

We'll cover the following...

As a reminder, let’s recap the rules of the FizzBuzz kata. It’s a function that accepts a number as the input and returns a string depending on the following conditions:

  • If the number is divisible by three, it returns Fizz.
  • If the number is divisible by five, it returns Buzz.
  • If the number is divisible by three and five, it returns FizzBuzz.
  • If the number is neither divisible by three nor by five, it returns a string representation of that number.

So far, we managed the most trivial example which used 1 as the input argument. Now, let’s add more tests for the fourth requirement.

Passing 2 to the FizzBuzz function

Let’s start with a simple scenario for the FizzBuzz function, which consists of passing the value 2 to it.

The Red phase

package fizzbuzz

import (
	"strconv"
	"testing"

	"github.com/stretchr/testify/assert"
)

func TestFizzBuzz(t *testing.T) {
	// arrange
	input := 1

	// act
	got := FizzBuzz(input)

	// assert
	assert.Equal(t, strconv.Itoa(input), got)
}

func TestFizzBuzz_Two(t *testing.T) {
	// arrange
	input := 2

	// act
	got := FizzBuzz(input)

	// assert
	if got != "2" {
		t.Errorf(`expected "2" but got %q`, got)
	}
}
Red phase for the value of 2

Here, we’re back in the Red stage of the TDD cycle. Our solution ...