Use `go-httpbin` to run tests locally and avoid remote calls to `httpbin.org`

https://github.com/mccutchen/go-httpbin is MIT licensed and implements httpbin interfaces in Golang. 

Combining this package with `httptest.Server` allows client unit tests to run entirely locally with no dependency on remote calls to httpbin.org

go.mod

@@ -9,6 +9,7 @@ require (
 	github.com/gorilla/mux v1.8.0
 	github.com/lib/pq v1.10.9
 	github.com/matrix-org/gomatrix v0.0.0-20220926102614-ceba4d9f7530
+	github.com/mccutchen/go-httpbin/v2 v2.9.1
 	github.com/prometheus/client_golang v1.16.0
 	github.com/rylans/getlang v0.0.0-20201227074721-9e7f44ff8aa0
 	github.com/tdewolff/minify/v2 v2.12.7

go.sum

@@ -33,6 +33,8 @@ github.com/matrix-org/gomatrix v0.0.0-20220926102614-ceba4d9f7530/go.mod h1:/gBX
 github.com/matryer/try v0.0.0-20161228173917-9ac251b645a2/go.mod h1:0KeJpeMD6o+O4hW7qJOT7vyQPKrWmj26uf5wMc/IiIs=
 github.com/matttproud/golang_protobuf_extensions v1.0.4 h1:mmDVorXM7PCGKw94cs5zkfA9PSy5pEvNWRP0ET0TIVo=
 github.com/matttproud/golang_protobuf_extensions v1.0.4/go.mod h1:BSXmuO+STAnVfrANrmjBb36TMTDstsz7MSK+HVaYKv4=
+github.com/mccutchen/go-httpbin/v2 v2.9.1 h1:blH3ecpqy7aQ9IHFjO9Xrmkfuv80rACnrg6M53gra8A=
+github.com/mccutchen/go-httpbin/v2 v2.9.1/go.mod h1:+DBHcmg6EOeoizuiOI8iL12VIHXx+9YQNlz+gjB9uxk=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/pquerna/cachecontrol v0.1.0 h1:yJMy84ti9h/+OEWa752kBTKv4XC30OtVVHYv/8cTqKc=

http/client/client_test.go

@@ -0,0 +1,70 @@
+// SPDX-FileCopyrightText: Copyright The Miniflux Authors. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package client // import "miniflux.app/http/client"
+
+import (
+	"fmt"
+	"net/http/httptest"
+	"os"
+	"testing"
+
+	"github.com/mccutchen/go-httpbin/v2/httpbin"
+)
+
+var srv *httptest.Server
+
+func TestMain(m *testing.M) {
+	srv = httptest.NewServer(httpbin.New())
+	exitCode := m.Run()
+	srv.Close()
+	os.Exit(exitCode)
+}
+
+func MakeClient(path string) *Client {
+	return New(fmt.Sprintf("%s%s", srv.URL, path))
+}
+
+func TestClientWithDelay(t *testing.T) {
+	clt := MakeClient("/delay/5")
+	clt.ClientTimeout = 1
+	_, err := clt.Get()
+	if err == nil {
+		t.Fatal(`The client should stops after 1 second`)
+	}
+}
+
+func TestClientWithError(t *testing.T) {
+	clt := MakeClient("/status/502")
+	clt.ClientTimeout = 5
+	response, err := clt.Get()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if response.StatusCode != 502 {
+		t.Fatalf(`Unexpected response status code: %d`, response.StatusCode)
+	}
+
+	if !response.HasServerFailure() {
+		t.Fatal(`A 502 error is considered as server failure`)
+	}
+}
+
+func TestClientWithResponseTooLarge(t *testing.T) {
+	clt := MakeClient("/bytes/100")
+	clt.ClientMaxBodySize = 10
+	_, err := clt.Get()
+	if err == nil {
+		t.Fatal(`The client should fails when reading a response too large`)
+	}
+}
+
+func TestClientWithBasicAuth(t *testing.T) {
+	clt := MakeClient("/basic-auth/testuser/testpassword")
+	clt.WithCredentials("testuser", "testpassword")
+	_, err := clt.Get()
+	if err != nil {
+		t.Fatalf(`The client should be authenticated successfully: %v`, err)
+	}
+}