Medium Article: Unit Tests: A Form of Documentation. Exhibit "Express expectations of the current functionality"

Test_functionA.go

func Test_functionA(t *testing.T) {
	type args struct {
		a int
		b int
	}
	tests := []struct {
		name    string
		args    args
		want    int
		wantErr bool
	}{
		{
			name: "successful case of adding 6 and 10",
			args: args{
				a: 6,
				b: 10,
			},
			want:    16,
			wantErr: false,
		},
		{
			name: "if one of the numbers is odd, return an error",
			args: args{
				a: 6,
				b: 9,
			},
			want:    0,
			wantErr: true,
		},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			got, err := addEvenNumbers(tt.args.a, tt.args.b)
			if (err != nil) != tt.wantErr {
				t.Errorf("addEvenNumbers() error = %v, wantErr %v", err, tt.wantErr)
				return
			}
			if got != tt.want {
				t.Errorf("addEvenNumbers() = %v, want %v", got, tt.want)
			}
		})
	}
}