main.go

package main

// input
// process(input) = result
// expected
// result == expected

// 90
// B

// A

func Grading(score int) string {
	if score > 90 {
		score = 90
	} else if score < 60 {
		score += 5
	}

	var grade string

	if score > 90 {
		grade = "A"
	} else if score > 80 {
		grade = "B"
	} else if score > 70 {
		grade = "C"
	} else if score > 60 {
		grade = "D"
	} else {
		grade = "E"
	}

	return grade
}

type Person struct {
	Name string
}

func (p *Person) Walk() string {
	return "tap tap dor"
}

main_test.go

package main

import (
	"testing"

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

func TestGrading(t *testing.T) {
	testcases := []struct {
		name     string
		input    int
		expected string
	}{
		{

			name: `
			Given score more than / equal 90
			When do grading
			Then should get grade B`,
			input:    90,
			expected: "B",
		},
		{
			input:    60,
			expected: "E",
		},
	}

	for _, tc := range testcases {
		t.Run(tc.name, func(t *testing.T) {
			result := Grading(tc.input)
			assert.Equal(t, tc.expected, result)
		})

	}
}

func TestPerson_Walk(t *testing.T) {
	type fields struct {
		Name string
	}
	tests := []struct {
		name   string
		fields fields
		want   string
	}{
		{
			name: "Case #1. Person Walk",
			want: "tap tap",
		},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			p := &Person{
				Name: tt.fields.Name,
			}

			result := p.Walk()
			assert.Equal(t, tt.want, result)

			// if got := p.Walk(); got != tt.want {
			// 	t.Errorf("Person.Walk() = %v, want %v", got, tt.want)
			// }
		})
	}
}