Initial commit

metrics/prometheus/prometheus_test.go

@@ -0,0 +1,61 @@
+package prometheus
+
+import (
+	"fmt"
+	stdprometheus "github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+	"globalfintech/golib/metrics"
+	"io/ioutil"
+	"math/rand"
+	"net/http"
+	"net/http/httptest"
+	"regexp"
+	"strconv"
+	"testing"
+)
+
+func TestCounter(t *testing.T) {
+	s := httptest.NewServer(promhttp.Handler())
+	defer s.Close()
+
+	scrape := func() string {
+		resp, _ := http.Get(s.URL)
+		buf, _ := ioutil.ReadAll(resp.Body)
+		return string(buf)
+	}
+
+	namespace, subsystem, name := "ns", "ss", "foo"
+	re := regexp.MustCompile(namespace + `_` + subsystem + `_` + name + `{alpha="alpha-value",beta="beta-value"} ([0-9\.]+)`)
+
+	counter := NewCounterFrom(stdprometheus.CounterOpts{
+		Namespace: namespace,
+		Subsystem: subsystem,
+		Name:      name,
+		Help:      "This is the help string.",
+	}, []string{"alpha", "beta"}).With("beta", "beta-value", "alpha", "alpha-value") // order shouldn't matter
+
+	value := func() float64 {
+		matches := re.FindStringSubmatch(scrape())
+		f, _ := strconv.ParseFloat(matches[1], 64)
+		return f
+	}
+	want := FillCounter(counter)
+	if have := value(); want != have {
+		t.Fatal(fmt.Errorf("want %f, have %f", want, have))
+	}
+
+}
+
+// FillCounter puts some deltas through the counter and returns the total value.
+func FillCounter(counter metrics.Counter) float64 {
+	a := rand.Perm(100)
+	n := rand.Intn(len(a))
+
+	var want float64
+	for i := 0; i < n; i++ {
+		f := float64(a[i])
+		counter.Add(f)
+		want += f
+	}
+	return want
+}