test: Add unit test for internal/trace/metrics.go

internal/trace/metrics_test.go

@@ -0,0 +1,32 @@
+package trace
+
+import (
+	"testing"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/stretchr/testify/assert"
+)
+
+func Test_metricsSetup(t *testing.T) {
+	// Reset any existing metrics
+	prometheus.DefaultRegisterer = prometheus.NewRegistry()
+
+	// Call metricsSetup
+	metricsSetup()
+
+	// Verify TracingProcessCount metric was created with correct parameters
+	assert.NotNil(t, TracingProcessCount)
+	assert.Equal(t, "datakit", TracingProcessCount.Desc().Namespace)
+	assert.Equal(t, "input", TracingProcessCount.Desc().Subsystem)
+	assert.Equal(t, "tracing_total", TracingProcessCount.Desc().Name)
+	assert.Equal(t, "The total links number of Trace processed by the trace module", TracingProcessCount.Desc().Help)
+	assert.Equal(t, []string{"input", "service"}, TracingProcessCount.Desc().VariableLabels)
+
+	// Verify tracingSamplerCount metric was created with correct parameters
+	assert.NotNil(t, tracingSamplerCount)
+	assert.Equal(t, "datakit", tracingSamplerCount.Desc().Namespace)
+	assert.Equal(t, "input", tracingSamplerCount.Desc().Subsystem)
+	assert.Equal(t, "sampler_total", tracingSamplerCount.Desc().Name)
+	assert.Equal(t, "The sampler number of Trace processed by the trace module", tracingSamplerCount.Desc().Help)
+	assert.Equal(t, []string{"input", "service"}, tracingSamplerCount.Desc().VariableLabels)
+}