cli-utils/pkg/testutil/matcher.go

139 lines
3.5 KiB
Go

// Copyright 2020 The Kubernetes Authors.
// SPDX-License-Identifier: Apache-2.0
//
package testutil
import (
"errors"
"fmt"
"reflect"
"strings"
"testing"
"github.com/google/go-cmp/cmp"
"github.com/google/go-cmp/cmp/cmpopts"
"github.com/onsi/gomega/format"
)
// Equal returns a matcher for use with Gomega that uses go-cmp's cmp.Equal to
// compare and cmp.Diff to show the difference, if there is one.
//
// Example Usage:
// Expect(receivedEvents).To(testutil.Equal(expectedEvents))
func Equal(expected interface{}) *cmpMatcher {
return &cmpMatcher{expected: expected}
}
type cmpMatcher struct {
expected interface{}
explanation error
}
func (cm *cmpMatcher) Match(actual interface{}) (bool, error) {
match := cmp.Equal(actual, cm.expected, cmpopts.EquateErrors())
if !match {
cm.explanation = errors.New(cmp.Diff(actual, cm.expected, cmpopts.EquateErrors()))
}
return match, nil
}
func (cm *cmpMatcher) FailureMessage(actual interface{}) string {
return format.Message(actual, "to deeply equal", cm.expected) +
"\nDiff:\n" + indent(cm.explanation.Error(), 1)
}
func (cm *cmpMatcher) NegatedFailureMessage(actual interface{}) string {
return format.Message(actual, "not to deeply equal", cm.expected) +
"\nDiff:\n" + indent(cm.explanation.Error(), 1)
}
func indent(in string, indentation uint) string {
indent := strings.Repeat(format.Indent, int(indentation))
lines := strings.Split(in, "\n")
return indent + strings.Join(lines, fmt.Sprintf("\n%s", indent))
}
// EqualErrorType returns an error with an Is(error)bool function that matches
// any error with the same type as the supplied error.
//
// Use with testutil.Equal to handle error comparisons.
func EqualErrorType(err error) equalErrorType {
return equalErrorType{
err: err,
}
}
type equalErrorType struct {
err error
}
func (e equalErrorType) Error() string {
return "EqualErrorType"
}
func (e equalErrorType) Is(err error) bool {
if err == nil {
return false
}
return reflect.TypeOf(e.err) == reflect.TypeOf(err)
}
func (e equalErrorType) Unwrap() error {
return e.err
}
// EqualErrorString returns an error with an Is(error)bool function that matches
// any error with the same Error() as the supplied string value.
//
// Use with testutil.Equal to handle error comparisons.
func EqualErrorString(err string) equalErrorString {
return equalErrorString{
err: err,
}
}
// equalError is an error that matches any non-nil error of the specified type.
type equalErrorString struct {
err string
}
func (e equalErrorString) Error() string {
return e.err
}
func (e equalErrorString) Is(err error) bool {
if err == nil {
return false
}
return e.err == err.Error()
}
// AssertEqual fails the test if the actual value does not deeply equal the
// expected value. Prints a diff on failure.
func AssertEqual(t *testing.T, actual, expected interface{}) {
t.Helper() // print the caller's file:line, instead of this func, on failure
matcher := Equal(expected)
match, err := matcher.Match(actual)
if err != nil {
t.Errorf("errored testing equality: %s", err)
}
if !match {
t.Error(matcher.FailureMessage(actual))
}
}
// AssertNotEqual fails the test if the actual value deeply equals the
// expected value. Prints a diff on failure.
func AssertNotEqual(t *testing.T, actual, expected interface{}) {
t.Helper() // print the caller's file:line, instead of this func, on failure
matcher := Equal(expected)
match, err := matcher.Match(actual)
if err != nil {
t.Errorf("errored testing equality: %s", err)
}
if match {
t.Error(matcher.NegatedFailureMessage(actual))
}
}