HaveKeyValue gomega matcher

have_key_value_matcher.go

package metrics

import (
	"fmt"
	"github.com/onsi/gomega/format"
	"github.com/onsi/gomega/matchers"
	"github.com/onsi/gomega/types"
	"reflect"
	"strings"
)

// HaveKeyValueMatcher is a wrapper around matchers.HaveKeyWithValueMatcher that displays failures as:
//   Expected
//      map_key: actual_value
//  to be
//      map_key: expected_value
type HaveKeyValueMatcher struct {
	matchers.HaveKeyWithValueMatcher
}

// HaveKeyValue is a wrapper around gomega.HaveKeyWithValue that displays failures as:
//     Expected
//         map_key: actual_value
//     to be
//         map_key: expected_value
//
//  Example:
//      Eventually(getMapWithResults).Should(SatisfyAll(
//  	    HaveKeyValue("result", "ok"),
//  	    HaveKeyValue("type", "message"),
//      ))
//
//  matchers.HaveKeyWithValueMatcher failure output:
//  	Expected
//          <map[string]string | len:4>: {
//  		    "foo": "random value",
//  		    "bar": "another random value",
//  		    "result": "OK",
//  		    "type": "message",
//  		}
//  	to have {key: value}
//          <map[interface {}]interface {} | len:1>: {
//              "result": "ok",
//          }
//
//  HaveKeyValueMatcher failure output:
//  	Expected
//          result: OK
//  	to be
//          result: ok
func HaveKeyValue(key interface{}, value interface{}) types.GomegaMatcher {
	return &HaveKeyValueMatcher{
		matchers.HaveKeyWithValueMatcher{
			Key:   key,
			Value: value,
		},
	}
}

// FailureMessage overrides the matchers.HaveKeyWithValueMatcher to display are more helpful message
func (matcher *HaveKeyValueMatcher) FailureMessage(actual interface{}) (message string) {
	actType := reflect.TypeOf(actual)
	keyType := reflect.TypeOf(matcher.Key)
	valType := reflect.TypeOf(matcher.Value)
	if actType.Kind() != reflect.Map || !actType.Key().AssignableTo(keyType) || !actType.Elem().AssignableTo(valType) {
		var expected = reflect.MakeMap(reflect.MapOf(keyType, valType)).Interface()
		return format.Message(actual, "to be", expected)
	}
	key := matcher.Key
	expVal := matcher.Value
	actVal := reflect.ValueOf(actual).MapIndex(reflect.ValueOf(key))
	if !actVal.IsValid() {
		actVal = reflect.New(valType).Elem()
	}
	indent := strings.Repeat(format.Indent, 1)

	return fmt.Sprintf("Expected\n%s%s: %v\nto be\n%s%s: %v", indent, key, actVal, indent, key, expVal)
}