collections/optional_test.go

package collections

import (
	"strings"
	"testing"

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

func TestIsPresent(t *testing.T) {
	tests := map[string]struct {
		optional       Optional[string]
		expectedResult bool
	}{
		"not present": {
			optional:       Optional[string]{},
			expectedResult: false,
		},
		"present": {
			optional: Optional[string]{
				present: true,
			},
			expectedResult: true,
		},
	}

	for name, tc := range tests {
		name, tc := name, tc
		t.Run(name, func(t *testing.T) {
			require.Equal(t, tc.expectedResult, tc.optional.IsPresent())
		})
	}
}

func TestGet(t *testing.T) {
	tests := map[string]struct {
		optional       Optional[string]
		expectedResult string
	}{
		"not present": {
			optional:       Optional[string]{},
			expectedResult: "",
		},
		"present": {
			optional: Optional[string]{
				e:       "foo",
				present: true,
			},
			expectedResult: "foo",
		},
	}

	for name, tc := range tests {
		name, tc := name, tc
		t.Run(name, func(t *testing.T) {
			require.Equal(t, tc.expectedResult, tc.optional.Get())
		})
	}
}

func TestOrElse(t *testing.T) {
	tests := map[string]struct {
		optional       Optional[string]
		expectedResult string
	}{
		"not present": {
			optional:       Optional[string]{},
			expectedResult: "bar",
		},
		"present": {
			optional: Optional[string]{
				e:       "foo",
				present: true,
			},
			expectedResult: "foo",
		},
	}

	for name, tc := range tests {
		name, tc := name, tc
		t.Run(name, func(t *testing.T) {
			require.Equal(t, tc.expectedResult, tc.optional.OrElse("bar"))
		})
	}
}

func TestOrElseGet(t *testing.T) {
	tests := map[string]struct {
		optional       Optional[string]
		expectedResult string
	}{
		"not present": {
			optional:       Optional[string]{},
			expectedResult: "bar",
		},
		"present": {
			optional: Optional[string]{
				e:       "foo",
				present: true,
			},
			expectedResult: "foo",
		},
	}

	for name, tc := range tests {
		name, tc := name, tc
		t.Run(name, func(t *testing.T) {
			require.Equal(t, tc.expectedResult, tc.optional.OrElseGet(func() string {
				return "bar"
			}))
		})
	}
}

func TestTransform(t *testing.T) {
	given := &Optional[string]{
		e:       "foo",
		present: true,
	}

	transformer := func(s string) string {
		return strings.ToUpper(s)
	}

	result := MapOptional(given, transformer)

	require.Equal(t, "FOO", result.Get())
}