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Learning Test-Driven Development with Go

FizzBuzz: "Fizz" Requirement

Explore writing tests and implementing the Fizz requirement in FizzBuzz using test-driven development in Go. Understand how to handle numbers divisible by 3 with iterative Red-Green-Refactor steps to build flexible, passing code.

We'll cover the following...

Fizz scenario

So far, we’ve only dealt with the not divisible scenario, which only covers the numbers not divisible by 3 and 5. In this lesson, let’s build the Fizz feature.

Handling input 3

As a reminder, our function should give back Fizz when the number passed is divisible by 3.

The Red phase

To obey the TDD constraints, we need to start writing a test that will take us to the Red stage:

package fizzbuzz

import (
	"testing"

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

func TestFizzBuzz(t *testing.T) {
	// arrange
	testSuite := []struct {
		name     string
		input    int
		expected string
	}{
		{
			"ShouldReturnOne_WhenOneIsPassed",
			1,
			"1",
		},
		{
			"ShouldReturnTwo_WhenTwoIsPassed",
			2,
			"2",
		},
		{
			"ShouldReturnFour_WhenFourIsPassed",
			4,
			"4",
		},
		{
			"ShouldReturnFizz_WhenThreeIsPassed",
			3,
			"Fizz",
		},
	}

	for _, tt := range testSuite {
		t.Run(tt.name, func(t *testing.T) {
			// act
			got := FizzBuzz(tt.input)

			// assert
			assert.Equal(t, tt.expected, got)
		})
	}
}
Red phase for the value of "3"

To get into the Red area, we added another test to our testSuite variable. This test ...