Add replication slot test

Signed-off-by: Felix Yuan <felix.yuan@reddit.com>

Author: Sticksman

collector/replication_slots.go

@@ -47,19 +47,22 @@ var pgReplicationSlotConfirmedFlushLSN = prometheus.NewDesc(
 
 var pgReplicationSlotActive = prometheus.NewDesc(
 "pg_replication_slot_is_active",
-"last lsn confirmed flushed to the replication slot",
+"whether the replication slot is active or not",
 []string{"slot_name"}, nil,
 )
 
+var pgReplicationSlotQuery = `SELECT
+slot_name,
+pg_current_wal_lsn() - '0/0' AS current_wal_lsn,
+coalesce(confirmed_flush_lsn, '0/0') - '0/0',
+active
+FROM
+pg_replication_slots;
+`
+
 func (PGReplicationSlotCollector) Update(ctx context.Context, db *sql.DB, ch chan<- prometheus.Metric) error {
 rows, err := db.QueryContext(ctx,
-`SELECT
-slot_name,
-pg_current_wal_lsn() - '0/0' AS current_wal_lsn,
-coalesce(confirmed_flush_lsn, '0/0') - '0/0',
-active
-FROM
-pg_replication_slots;`)
+pgReplicationSlotQuery)
 if err != nil {
 return err
 }
@@ -70,10 +73,18 @@ func (PGReplicationSlotCollector) Update(ctx context.Context, db *sql.DB, ch cha
 var wal_lsn int64
 var flush_lsn int64
 var is_active bool
+var is_active_value int
+
 if err := rows.Scan(&slot_name, &wal_lsn, &flush_lsn, &is_active); err != nil {
 return err
 }
 
+if is_active {
+is_active_value = 1
+} else {
+is_active_value = 0
+}
+
 ch <- prometheus.MustNewConstMetric(
 pgReplicationSlotCurrentWalLSN,
 prometheus.GaugeValue, float64(wal_lsn), slot_name,
@@ -86,7 +97,7 @@ func (PGReplicationSlotCollector) Update(ctx context.Context, db *sql.DB, ch cha
 }
 ch <- prometheus.MustNewConstMetric(
 pgReplicationSlotActive,
-prometheus.GaugeValue, float64(flush_lsn), slot_name,
+prometheus.GaugeValue, float64(is_active_value), slot_name,
 )
 }
 if err := rows.Err(); err != nil {

collector/replication_slots_test.go

@@ -0,0 +1,89 @@
+package collector
+
+import (
+"context"
+"testing"
+
+"github.com/DATA-DOG/go-sqlmock"
+"github.com/prometheus/client_golang/prometheus"
+dto "github.com/prometheus/client_model/go"
+"github.com/smartystreets/goconvey/convey"
+)
+
+func TestPgReplicationSlotCollectorActive(t *testing.T) {
+db, mock, err := sqlmock.New()
+if err != nil {
+t.Fatalf("Error opening a stub db connection: %s", err)
+}
+defer db.Close()
+
+columns := []string{"slot_name", "current_wal_lsn", "confirmed_flush_lsn", "active"}
+rows := sqlmock.NewRows(columns).
+AddRow("test_slot", 5, 3, true)
+mock.ExpectQuery(sanitizeQuery(pgReplicationSlotQuery)).WillReturnRows(rows)
+
+ch := make(chan prometheus.Metric)
+go func() {
+defer close(ch)
+c := PGReplicationSlotCollector{}
+
+if err := c.Update(context.Background(), db, ch); err != nil {
+t.Errorf("Error calling PGPostmasterCollector.Update: %s", err)
+}
+}()
+
+expected := []MetricResult{
+{labels: labelMap{"slot_name": "test_slot"}, value: 5, metricType: dto.MetricType_GAUGE},
+{labels: labelMap{"slot_name": "test_slot"}, value: 3, metricType: dto.MetricType_GAUGE},
+{labels: labelMap{"slot_name": "test_slot"}, value: 1, metricType: dto.MetricType_GAUGE},
+}
+
+convey.Convey("Metrics comparison", t, func() {
+for _, expect := range expected {
+m := readMetric(<-ch)
+convey.So(expect, convey.ShouldResemble, m)
+}
+})
+if err := mock.ExpectationsWereMet(); err != nil {
+t.Errorf("there were unfulfilled exceptions: %s", err)
+}
+}
+
+func TestPgReplicationSlotCollectorInActive(t *testing.T) {
+db, mock, err := sqlmock.New()
+if err != nil {
+t.Fatalf("Error opening a stub db connection: %s", err)
+}
+defer db.Close()
+
+columns := []string{"slot_name", "current_wal_lsn", "confirmed_flush_lsn", "active"}
+rows := sqlmock.NewRows(columns).
+AddRow("test_slot", 6, 12, false)
+mock.ExpectQuery(sanitizeQuery(pgReplicationSlotQuery)).WillReturnRows(rows)
+
+ch := make(chan prometheus.Metric)
+go func() {
+defer close(ch)
+c := PGReplicationSlotCollector{}
+
+if err := c.Update(context.Background(), db, ch); err != nil {
+t.Errorf("Error calling PGPostmasterCollector.Update: %s", err)
+}
+}()
+
+expected := []MetricResult{
+{labels: labelMap{"slot_name": "test_slot"}, value: 6, metricType: dto.MetricType_GAUGE},
+{labels: labelMap{"slot_name": "test_slot"}, value: 0, metricType: dto.MetricType_GAUGE},
+}
+
+convey.Convey("Metrics comparison", t, func() {
+for _, expect := range expected {
+m := readMetric(<-ch)
+convey.So(expect, convey.ShouldResemble, m)
+}
+})
+if err := mock.ExpectationsWereMet(); err != nil {
+t.Errorf("there were unfulfilled exceptions: %s", err)
+}
+
+}