Add unit-test for Run method and other improvements

promremote/client_test.go

@@ -1,11 +1,15 @@
 package promremote
 
 import (
+	"bytes"
 	"encoding/base64"
+	"log"
 	"net/http"
 	"net/http/httptest"
+	"os"
 	"reflect"
 	"testing"
+	"time"
 
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/collectors"
@@ -161,3 +165,25 @@ func TestCollect(t *testing.T) {
 	assert.Nil(err)
 	assert.NotEmpty(ts)
 }
+
+func TestRun(t *testing.T) {
+	reg := prometheus.NewRegistry()
+	reg.MustRegister(collectors.NewBuildInfoCollector())
+
+	c, _ := NewWriteClient("testendpoint", "test", "test", reg)
+
+	var buf bytes.Buffer
+	log.SetOutput(&buf)
+	t.Cleanup(func() {
+		log.SetOutput(os.Stderr)
+	})
+
+	quit := make(chan bool)
+	c.Run(time.Second, quit)
+
+	<-time.After(time.Second * 2)
+	quit <- true
+
+	output := buf.String()
+	assert.Contains(t, output, "ERROR Failed to send metrics to remote endpoint err=", "Should output error to log and not fail")
+}

promremote/errors.go

@@ -34,7 +34,7 @@ type ErrRemoteWriteFailed struct {
 	Body       string
 }
 
-func NewErrRemoteWriteFailed(status int, resBody io.ReadCloser) *ErrRemoteWriteFailed {
+func NewErrRemoteWriteFailed(status int, resBody io.ReadCloser) error {
 	var body string
 	b, err := io.ReadAll(resBody)
 	if err != nil {

promremote/errors_test.go

@@ -2,16 +2,31 @@ package promremote
 
 import (
 	"io"
+	"os"
 	"strings"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
 )
 
-func TestNewErrRemoteWriteFailed(t *testing.T) {
-	result := &ErrRemoteWriteFailed{StatusCode: 400, Body: "testresult"}
-	r := io.NopCloser(strings.NewReader(result.Body))
-	defer r.Close()
-	err := NewErrRemoteWriteFailed(400, r)
-	assert.Equal(t, result, err)
+func TestErrRemoteWriteFailed(t *testing.T) {
+	t.Run("New", func(t *testing.T) {
+		assert := assert.New(t)
+
+		expectedResult := &ErrRemoteWriteFailed{StatusCode: 400, Body: "testresult"}
+
+		r := io.NopCloser(strings.NewReader(expectedResult.Body))
+		defer r.Close()
+		result := NewErrRemoteWriteFailed(400, r).(*ErrRemoteWriteFailed)
+		assert.Equal(expectedResult, result, "Should read the response body")
+
+		f, err := os.Open("/dev/null")
+		if !assert.NoError(err, "Should not fail to open /dev/null") {
+			t.FailNow()
+		}
+		f.Close()
+		result = NewErrRemoteWriteFailed(400, f).(*ErrRemoteWriteFailed)
+		assert.Contains(result.Body, "file already closed", "Should return error of reader as body")
+	})
+
 }