add test for ConnectionInfo collector

internal/component/database_observability/mysql/collector/connection_info_test.go

@@ -0,0 +1,54 @@
+package collector
+
+import (
+	"context"
+	"fmt"
+	"strings"
+	"testing"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/testutil"
+	"github.com/stretchr/testify/require"
+)
+
+func TestConnectionInfoRun(t *testing.T) {
+	const baseExpectedMetrics = `
+	# HELP connection_info Information about the connection
+	# TYPE connection_info gauge
+	connection_info{db_instance_identifier="%s",provider_name="%s",region="%s"} 1
+`
+
+	testCases := []struct {
+		name            string
+		dsn             string
+		expectedMetrics string
+	}{
+		{
+			name:            "generic dsn",
+			dsn:             "user:pass@tcp(localhost:3306)/db",
+			expectedMetrics: fmt.Sprintf(baseExpectedMetrics, "", "", ""),
+		},
+		{
+			name:            "AWS/RDS dsn",
+			dsn:             "user:pass@tcp(products-db.abc123xyz.us-east-1.rds.amazonaws.com:3306)/db",
+			expectedMetrics: fmt.Sprintf(baseExpectedMetrics, "products-db", "aws", "us-east-1"),
+		},
+	}
+
+	for _, tc := range testCases {
+		reg := prometheus.NewRegistry()
+
+		collector, err := NewConnectionInfo(ConnectionInfoArguments{
+			DSN:      tc.dsn,
+			Registry: reg,
+		})
+		require.NoError(t, err)
+		require.NotNil(t, collector)
+
+		err = collector.Run(context.Background())
+		require.NoError(t, err)
+
+		err = testutil.GatherAndCompare(reg, strings.NewReader(tc.expectedMetrics))
+		require.NoError(t, err)
+	}
+}