Errors: Allow using Base as an error type (#53824)

pkg/util/errutil/errors_test.go

@@ -0,0 +1,74 @@
+package errutil
+
+import (
+	"errors"
+	"fmt"
+	"reflect"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestBase_Is(t *testing.T) {
+	baseNotFound := NewBase(StatusNotFound, "test:not-found")
+	baseInternal := NewBase(StatusInternal, "test:internal")
+
+	tests := []struct {
+		Base            Base
+		Other           error
+		Expect          bool
+		ExpectUnwrapped bool
+	}{
+		{
+			Base:   Base{},
+			Other:  errors.New(""),
+			Expect: false,
+		},
+		{
+			Base:   Base{},
+			Other:  Base{},
+			Expect: true,
+		},
+		{
+			Base:   Base{},
+			Other:  Error{},
+			Expect: true,
+		},
+		{
+			Base:   baseNotFound,
+			Other:  baseNotFound,
+			Expect: true,
+		},
+		{
+			Base:   baseNotFound,
+			Other:  baseNotFound.Errorf("this is an error derived from baseNotFound, it is considered to be equal to baseNotFound"),
+			Expect: true,
+		},
+		{
+			Base:   baseNotFound,
+			Other:  baseInternal,
+			Expect: false,
+		},
+		{
+			Base:            baseInternal,
+			Other:           fmt.Errorf("wrapped, like a burrito: %w", baseInternal.Errorf("oh noes")),
+			Expect:          false,
+			ExpectUnwrapped: true,
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(fmt.Sprintf(
+			"Base '%s' == '%s' of type %s = %v (%v unwrapped)",
+			tc.Base.Error(),
+			tc.Other.Error(),
+			reflect.TypeOf(tc.Other),
+			tc.Expect,
+			tc.Expect || tc.ExpectUnwrapped,
+		), func(t *testing.T) {
+			assert.Equal(t, tc.Expect, tc.Base.Is(tc.Other), "direct comparison")
+			assert.Equal(t, tc.Expect, errors.Is(tc.Base, tc.Other), "comparison using errors.Is with other as target")
+			assert.Equal(t, tc.Expect || tc.ExpectUnwrapped, errors.Is(tc.Other, tc.Base), "comparison using errors.Is with base as target, should unwrap other")
+		})
+	}
+}