Added test

Makefile

@@ -113,6 +113,10 @@ update-vendor:
 	@$(PULSAR) go flatten -V $(VENDORDIR) $(VENDORDIR)
 	@${MAKE} -B -s clean
 
+.PHONY: run-tests
+run-tests: $(GOBUILDDIR)
+	GOPATH=$(GOBUILDDIR) go test $(REPOPATH)
+
 docker: build
 	for arch in $(ARCHS); do \
 		docker build --build-arg=GOARCH=$$arch -t $(DOCKERIMAGE)-$$arch . ;\

exporter_test.go

@@ -0,0 +1,74 @@
+//
+// DISCLAIMER
+//
+// Copyright 2018 ArangoDB GmbH, Cologne, Germany
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+// Copyright holder is ArangoDB GmbH, Cologne, Germany
+//
+// Author Ewout Prangsma
+//
+
+package main
+
+import (
+	"fmt"
+	_ "net/http/pprof"
+	"strings"
+	"testing"
+
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+// TestMetric tests the result of metricKey & newMetric for various inputs.
+func TestMetric(t *testing.T) {
+	g1 := StatisticGroup{
+		Group:       "g1",
+		Name:        "g1-name",
+		Description: "Something g1",
+	}
+	tests := []struct {
+		Group               StatisticGroup
+		Figure              StatisticFigure
+		Postfix             string
+		KeyResult           string
+		CollectionPostfixes []string
+	}{
+		{g1, StatisticFigure{"g1", "f1", "f1-name", "descr-f1", FigureTypeAccumulated, "", nil}, "_pf", "g1-name_f1-name_pf", []string{""}},
+		{g1, StatisticFigure{"g1", "f1", "f1-name", "descr-f1", FigureTypeAccumulated, "tick", nil}, "_pf", "g1-name_f1-name_pf_tick", []string{""}},
+		{g1, StatisticFigure{"g1", "f2", "f2-name", "descr-f2", FigureTypeDistribution, "", []float64{0.1, 0.2}}, "_pf", "g1-name_f2-name_pf", []string{"_sum", "_count", "_bucket"}},
+	}
+
+	for i, test := range tests {
+		result := metricKey(test.Group, test.Figure, test.Postfix)
+		if result != test.KeyResult {
+			t.Errorf("metricKey for test %d failed: got '%s', expected '%s'", i, result, test.KeyResult)
+		}
+		colls := newMetric(test.Group, test.Figure)
+		if len(colls) != len(test.CollectionPostfixes) {
+			t.Errorf("newMetric for test %d returns unexpected #collectors: got %d, expected %d", i, len(colls), len(test.CollectionPostfixes))
+		} else {
+			for ci, c := range colls {
+				descrChan := make(chan *prometheus.Desc, 1)
+				c.Describe(descrChan)
+				d := <-descrChan
+				result := d.String()
+				expectedPostfix := test.CollectionPostfixes[ci]
+				if !strings.Contains(result, fmt.Sprintf("%s\", help", expectedPostfix)) {
+					t.Errorf("newMetric for test %d returns collector %d with wrong expectation. got '%s', expected it to contain '%s'", i, ci, result, expectedPostfix)
+				}
+			}
+		}
+	}
+}