external-dns/internal/testutils/metrics.go

/*
Copyright 2025 The Kubernetes Authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

	http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package testutils

import (
	"testing"

	"github.com/prometheus/client_golang/prometheus"
	dto "github.com/prometheus/client_model/go"
	"github.com/stretchr/testify/assert"
)

// TestHelperVerifyMetricsGaugeVectorWithLabels verifies that a prometheus.GaugeVec metric with specific labels has the expected value.
//
// Example usage:
//
//	labels := map[string]string{"method": "GET", "status": "200"}
//	TestHelperVerifyMetricsGaugeVectorWithLabels(t, 42.0, myGaugeVec, labels)
func TestHelperVerifyMetricsGaugeVectorWithLabels(t *testing.T, expected float64, metric prometheus.GaugeVec, labels map[string]string) {
	TestHelperVerifyMetricsGaugeVectorWithLabelsFunc(t, expected, assert.Equal, metric, labels)
}

// TestHelperVerifyMetricsGaugeVectorWithLabelsFunc is a helper function that verifies a prometheus.GaugeVec metric with specific labels using a custom assertion function.
func TestHelperVerifyMetricsGaugeVectorWithLabelsFunc(t *testing.T, expected float64, aFunc assert.ComparisonAssertionFunc, metric prometheus.GaugeVec, labels map[string]string) {
	t.Helper()

	g, err := metric.MetricVec.GetMetricWith(labels)
	assert.NoError(t, err)

	var m dto.Metric
	err = g.Write(&m)
	assert.NoError(t, err)

	assert.NotNil(t, m.Gauge)

	aFunc(t, expected, *m.Gauge.Value, "Expected gauge value does not match the actual value", labels)
}