chore: add more tests (#4042)

core/stat/remotewriter_test.go

@@ -1,6 +1,7 @@
 package stat
 
 import (
+	"errors"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -28,3 +29,14 @@ func TestRemoteWriterFail(t *testing.T) {
 	})
 	assert.NotNil(t, err)
 }
+
+func TestRemoteWriterError(t *testing.T) {
+	defer gock.Off()
+
+	gock.New("http://foo.com").ReplyError(errors.New("foo"))
+	writer := NewRemoteWriter("http://foo.com")
+	err := writer.Write(&StatReport{
+		Name: "bar",
+	})
+	assert.NotNil(t, err)
+}