Fix the NaN tests

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

Author: Sticksman

collector/pg_archiver_test.go

@@ -14,6 +14,7 @@ package collector
 
 import (
 "context"
+"math"
 "testing"
 
 "github.com/DATA-DOG/go-sqlmock"
@@ -56,3 +57,40 @@ func TestPgArchiverCollector(t *testing.T) {
 t.Errorf("there were unfulfilled exceptions: %s", err)
 }
 }
+
+func TestPgArchiverNaNCollector(t *testing.T) {
+db, mock, err := sqlmock.New()
+if err != nil {
+t.Fatalf("Error opening a stub db connection: %s", err)
+}
+defer db.Close()
+
+inst := &instance{db: db}
+mock.ExpectQuery(sanitizeQuery(pgArchiverQuery)).WillReturnRows(sqlmock.NewRows([]string{"pending_wal_count"}).
+AddRow(math.NaN()))
+
+ch := make(chan prometheus.Metric)
+go func() {
+defer close(ch)
+c := PGArchiverCollector{}
+
+if err := c.Update(context.Background(), inst, ch); err != nil {
+t.Errorf("Error calling PGArchiverCollector.Update: %s", err)
+}
+}()
+
+expected := []MetricResult{
+{labels: labelMap{}, value: math.NaN(), metricType: dto.MetricType_GAUGE},
+}
+convey.Convey("Metrics comparison", t, func() {
+for _, expect := range expected {
+m := readMetric(<-ch)
+convey.So(expect.labels, convey.ShouldResemble, m.labels)
+convey.So(math.IsNaN(m.value), convey.ShouldResemble, math.IsNaN(expect.value))
+convey.So(expect.metricType, convey.ShouldEqual, m.metricType)
+}
+})
+if err := mock.ExpectationsWereMet(); err != nil {
+t.Errorf("there were unfulfilled exceptions: %s", err)
+}
+}

collector/pg_xid_test.go

@@ -65,9 +65,7 @@ func TestPgXidCollector(t *testing.T) {
 }
 }
 
-// This test is turned off for now
-// Because convey cannot compare NaN
-func xTestPgNanCollector(t *testing.T) {
+func TestPgNanCollector(t *testing.T) {
 db, mock, err := sqlmock.New()
 if err != nil {
 t.Fatalf("Error opening a stub db connection: %s", err)
@@ -101,7 +99,10 @@ func xTestPgNanCollector(t *testing.T) {
 convey.Convey("Metrics comparison", t, func() {
 for _, expect := range expected {
 m := readMetric(<-ch)
-convey.So(expect, convey.ShouldResemble, m)
+
+convey.So(expect.labels, convey.ShouldResemble, m.labels)
+convey.So(math.IsNaN(m.value), convey.ShouldResemble, math.IsNaN(expect.value))
+convey.So(expect.metricType, convey.ShouldEqual, m.metricType)
 }
 })
 if err := mock.ExpectationsWereMet(); err != nil {