pkg/telemetry/telemetry_test.go

@@ -117,6 +117,108 @@ func (t *tGatherer) Gather() ([]*io_prometheus_client.MetricFamily, error) {
 	return t.mf, nil
 }
 
+func TestMetricsCardinality(t *testing.T) {
+	counterType := io_prometheus_client.MetricType_COUNTER
+	histogramType := io_prometheus_client.MetricType_HISTOGRAM
+	gaugeHistogramType := io_prometheus_client.MetricType_GAUGE_HISTOGRAM
+	summaryType := io_prometheus_client.MetricType_SUMMARY
+
+	simpleCounter := prometheus.NewCounter(prometheus.CounterOpts{
+		Name: "test_counter",
+		Help: "test counter",
+	})
+
+	histogram3buckets := prometheus.NewHistogram(prometheus.HistogramOpts{
+		Name:    "3buckets_histogram",
+		Help:    "test histogram",
+		Buckets: []float64{1, 2, 3},
+	})
+
+	histogram5buckets := prometheus.NewHistogram(prometheus.HistogramOpts{
+		Name:    "5buckets_histogram",
+		Help:    "test histogram",
+		Buckets: []float64{1, 2, 3, 4, 5},
+	})
+	summary := prometheus.NewSummary(prometheus.SummaryOpts{
+		Name:       "test_summary",
+		Help:       "test summary",
+		Objectives: map[float64]float64{0.5: 0.05, 0.9: 0.01, 0.99: 0.001},
+	})
+
+	outputCounter := io_prometheus_client.Metric{}
+	simpleCounter.Write(&outputCounter)
+	testCounter := io_prometheus_client.MetricFamily{
+		Type: &counterType,
+		Metric: []*io_prometheus_client.Metric{
+			&outputCounter,
+		},
+	}
+
+	outputHistogram3Buckets := io_prometheus_client.Metric{}
+	histogram3buckets.Write(&outputHistogram3Buckets)
+	test3BucketsHistogram := io_prometheus_client.MetricFamily{
+		Type: &histogramType,
+		Metric: []*io_prometheus_client.Metric{
+			&outputHistogram3Buckets,
+		},
+	}
+
+	outputHistogram5Buckets := io_prometheus_client.Metric{}
+	histogram5buckets.Write(&outputHistogram5Buckets)
+	test5BucketsGaugeHistogram := io_prometheus_client.MetricFamily{
+		Type: &gaugeHistogramType,
+		Metric: []*io_prometheus_client.Metric{
+			&outputHistogram5Buckets,
+		},
+	}
+
+	outputSummary := io_prometheus_client.Metric{}
+	summary.Write(&outputSummary)
+	testSummary := io_prometheus_client.MetricFamily{
+		Type: &summaryType,
+		Metric: []*io_prometheus_client.Metric{
+			&outputSummary,
+		},
+	}
+
+	testcases := []struct {
+		name                string
+		mf                  []*io_prometheus_client.MetricFamily
+		expectedCardinality int
+	}{
+		{
+			"Simple Counter",
+			[]*io_prometheus_client.MetricFamily{&testCounter},
+			1,
+		},
+		{
+			"3 Buckets Histogram",
+			[]*io_prometheus_client.MetricFamily{&test3BucketsHistogram},
+			6,
+		},
+		{
+			"5 Buckets Gauge Histogram",
+			[]*io_prometheus_client.MetricFamily{&test5BucketsGaugeHistogram},
+			8,
+		},
+		{
+			"Summary",
+			[]*io_prometheus_client.MetricFamily{&testSummary},
+			5,
+		},
+	}
+	for _, tc := range testcases {
+		t.Run(tc.name, func(t *testing.T) {
+			testGatherer := tGatherer{
+				mf: tc.mf,
+			}
+			gotCardinality, err := metricsCardinality(&testGatherer)
+			require.NoError(t, err)
+			require.Equal(t, tc.expectedCardinality, gotCardinality)
+		})
+	}
+}
+
 func TestMetricsCardinality_NilHistogram(t *testing.T) {
 	histogramType := io_prometheus_client.MetricType_HISTOGRAM
 	gaugeHistogramType := io_prometheus_client.MetricType_GAUGE_HISTOGRAM