Fix the NaN test

Signed-off-by: Felix Yuan <[email protected]>

Author: Sticksman

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 +99,12 @@ func xTestPgNanCollector(t *testing.T) {
 	convey.Convey("Metrics comparison", t, func() {
 		for _, expect := range expected {
 			m := readMetric(<-ch)
-			convey.So(expect, convey.ShouldResemble, m)
+			if math.IsNaN(expect.value) {
+				// Assume the rest of it looks fine since the above test should properly exercise it
+				convey.So(math.IsNaN(m.value), convey.ShouldBeTrue)
+			} else {
+				convey.So(expect, convey.ShouldResemble, m)
+			}
 		}
 	})
 	if err := mock.ExpectationsWereMet(); err != nil {