Test Prometheus exporter target info sanitize

Author: kornerc

exporter/opentelemetry-exporter-prometheus/tests/test_prometheus_exporter.py

@@ -389,3 +389,27 @@ def test_target_info_disabled(self):
             )
             self.assertNotIn("os", prometheus_metric.samples[0].labels)
             self.assertNotIn("histo", prometheus_metric.samples[0].labels)
+
+    def test_target_info_sanitize(self):
+        metric_reader = PrometheusMetricReader()
+        provider = MeterProvider(
+            metric_readers=[metric_reader],
+            resource=Resource({"system.os": "Unix", "system.name": "Prometheus Target Sanitize"}),
+        )
+        meter = provider.get_meter("getting-started", "0.1.2")
+        counter = meter.create_counter("counter")
+        counter.add(1)
+        prometheus_metric = list(metric_reader._collector.collect())[0]
+
+        self.assertEqual(type(prometheus_metric), InfoMetricFamily)
+        self.assertEqual(prometheus_metric.name, "target")
+        self.assertEqual(
+            prometheus_metric.documentation, "Target metadata"
+        )
+        self.assertTrue(len(prometheus_metric.samples) == 1)
+        self.assertEqual(prometheus_metric.samples[0].value, 1)
+        self.assertTrue(len(prometheus_metric.samples[0].labels) == 2)
+        self.assertTrue("system_os" in prometheus_metric.samples[0].labels)
+        self.assertEqual(prometheus_metric.samples[0].labels["system_os"], "Unix")
+        self.assertTrue("system_name" in prometheus_metric.samples[0].labels)
+        self.assertEqual(prometheus_metric.samples[0].labels["system_name"], "Prometheus Target Sanitize")