assert.go

package ph

import (
	"fmt"
	"strings"
	"testing"

	"github.com/prometheus/client_golang/prometheus"
	"github.com/stretchr/testify/assert"
)

// AssertMetricExists asserts that a metric with the given fully-qualified name was gathered from
// gatherer. For Vec types that have no observations, it also checks registered descriptors if
// gatherer is a *TrackingRegistry.
func AssertMetricExists(t *testing.T, gatherer prometheus.Gatherer, name string) {
	t.Helper()

	g, err := gatherer.Gather()
	assert.NoError(t, err)
	for _, metric := range g {
		if metric.GetName() == name {
			return
		}
	}

	// Vec metrics with no observations don't appear in Gather; fall back to descriptor check.
	if tr, ok := gatherer.(*TrackingRegistry); ok {
		tr.mu.Lock()
		descs := make([]*prometheus.Desc, len(tr.descs))
		copy(descs, tr.descs)
		tr.mu.Unlock()
		needle := fmt.Sprintf("fqName: %q", name)
		for _, d := range descs {
			if strings.Contains(d.String(), needle) {
				return
			}
		}
	}

	assert.Fail(t, fmt.Sprintf("Metric %s not found", name))
}

// AssertMetricNotExists asserts that no metric with the given fully-qualified name was
// gathered from gatherer. It checks both Gather results and registered descriptors so
// that Vec metrics with no observations are also covered.
func AssertMetricNotExists(t *testing.T, gatherer prometheus.Gatherer, name string) {
	t.Helper()

	g, err := gatherer.Gather()
	assert.NoError(t, err)
	for _, metric := range g {
		if metric.GetName() == name {
			assert.Fail(t, fmt.Sprintf("Metric %s was found but should not exist", name))
			return
		}
	}

	// Also check descriptors for Vec metrics that have no observations yet.
	if tr, ok := gatherer.(*TrackingRegistry); ok {
		tr.mu.Lock()
		descs := make([]*prometheus.Desc, len(tr.descs))
		copy(descs, tr.descs)
		tr.mu.Unlock()
		needle := fmt.Sprintf("fqName: %q", name)
		for _, d := range descs {
			if strings.Contains(d.String(), needle) {
				assert.Fail(t, fmt.Sprintf("Metric %s was found in descriptors but should not exist", name))
				return
			}
		}
	}
}

// AssertMetricsCount asserts that exactly expectedCount metrics were gathered from gatherer.
func AssertMetricsCount(t *testing.T, gatherer prometheus.Gatherer, expectedCount int) {
	t.Helper()
	g, err := gatherer.Gather()
	assert.NoError(t, err)
	assert.Equal(t, expectedCount, len(g))
}