Function TestFormatErrorInternal

errbase/format_error_internal_test.go:117–302

TestFormatErrorInternal attempts to highlight some idiosyncrasies of the error formatting especially when used with multi-cause error structures. Comments on specific cases below outline some gaps that still require formatting tweaks.

(t *testing.T)

// structures. Comments on specific cases below outline some gaps that
// still require formatting tweaks.
func TestFormatErrorInternal(t *testing.T) {
	tests := []struct {
		name            string
		err             error
		expectedSimple  string
		expectedVerbose string
	}{
		{
			name:           "single wrapper",
			err:            fmt.Errorf("%w", fmt.Errorf("a%w", goErr.New("b"))),
			expectedSimple: "ab",
			expectedVerbose: `ab
(1)
Wraps: (2) ab
Wraps: (3) b
Error types: (1) *fmt.wrapError (2) *fmt.wrapError (3) *errors.errorString`,
		},
		{
			name:           "simple multi-wrapper",
			err:            goErr.Join(goErr.New("a"), goErr.New("b")),
			expectedSimple: "a\nb",
			// TODO(davidh): verbose test case should have line break
			// between `a` and `b` on second line.
			expectedVerbose: `a
(1) ab
Wraps: (2) b
Wraps: (3) a
Error types: (1) *errors.joinError (2) *errors.errorString (3) *errors.errorString`,
		},
		{
			name: "multi-wrapper with custom formatter and partial elide",
			err: NewWrapNoElideCauses("A",
				NewWrapNoElideCauses("C", goErr.New("3"), goErr.New("4")),
				NewWrapElideCauses("B", goErr.New("1"), goErr.New("2")),
			),
			expectedSimple: `A: B: C: 4: 3`, // 1 and 2 omitted because they are elided.
			expectedVerbose: `A: B: C: 4: 3
(1) A
Wraps: (2) B
└─ Wraps: (3) 2
└─ Wraps: (4) 1
Wraps: (5) C
└─ Wraps: (6) 4
└─ Wraps: (7) 3
Error types: (1) *errbase.wrapNoElideCauses (2) *errbase.wrapElideCauses (3) *errors.errorString (4) *errors.errorString (5) *errbase.wrapNoElideCauses (6) *errors.errorString (7) *errors.errorString`,
		},
		{
			name: "multi-wrapper with custom formatter and no elide",
			// All errors in this example omit eliding their children.
			err: NewWrapNoElideCauses("A",
				NewWrapNoElideCauses("B", goErr.New("1"), goErr.New("2")),
				NewWrapNoElideCauses("C", goErr.New("3"), goErr.New("4")),
			),
			expectedSimple: `A: C: 4: 3: B: 2: 1`,
			expectedVerbose: `A: C: 4: 3: B: 2: 1
(1) A
Wraps: (2) C
└─ Wraps: (3) 4