Testing

Tips

Most of the time, it’s pointless to fully check both the returned value and the error—only one of them will be set.

Test tables

Using anonoymous structs and a map is a good pattern.

Go
func TestGameAsk(t *testing.T) {
	tt := map[string]struct {
		input string
		want  []rune
	}{
		"5 characters in english": {
			input: "HELLO",
			want:  []rune("HELLO"),
		},
		"5 characters in arabic": {
			input: "مرحبا",
			want:  []rune("مرحبا"),
		},
	}

	for name, tc := range tt {
		t.Run(name, func(t *testing.T) {
			g := New(strings.NewReader(tc.input))

			got := g.ask()
			if !slices.Equal(got, tc.want) {
				t.Errorf("got = %v, want %v", string(got), string(tc.want))
			}
		})
	}
}

Test Tables with validator functions

Go
func TestConvert(t *testing.T) {
	tt := map[string]struct {
		amount   money.Amount
		to       money.Currency
		validate func(t *testing.T, got money.Amount, err error)
	}{
		"34.98 USD to EUR": {
			amount: money.Amount{},
			to:     money.Currency{},
			validate: func(t *testing.T, got money.Amount, err error) {
				if err != nil {
					t.Errorf("expected no error, got %s", err.Error())
				}
				expected := money.Amount{}
				if !reflect.DeepEqual(got, expected) {
					t.Errorf("expected %v, got %v", expected, got)
				}
			},
		},
	}
	for name, tc := range tt {
		t.Run(name, func(t *testing.T) {
			got, err := money.Convert(tc.amount, tc.to)
			tc.validate(t, got, err)
		})
	}
}

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