test(http): replace external httpbin.org with local test server for header tests

Gavel-Issue-Id: 2a55fc284b25da73528b29fa26876212
Claude-Session-Id: c6e82086-2045-406c-87b9-b03ac8b55bf1

Author: moshloop

http/http_test.go

@@ -2,10 +2,12 @@ package http_test
 
 import (
 	"context"
+	"encoding/json"
 	"fmt"
 	"net"
 	netHTTP "net/http"
-	"net/url"
+	"net/http/httptest"
+	"strings"
 	"testing"
 	"time"
 
@@ -146,53 +148,48 @@ func TestHTTP(t *testing.T) {
 	})
 
 	t.Run("Host Header", func(t *testing.T) {
-		uri, _ := url.Parse("https://httpbin.org/headers")
-		ips, err := net.LookupIP(uri.Host)
-		if err != nil {
-			t.Error(err.Error())
-		}
-
-		uriIP := *uri
-		uriIP.Host = ips[0].To4().String()
+		server := startHeadersServer(t)
 
+		const hostOverride = "httpbin.example.com"
 		resp, err := http.NewClient().
 			TraceToStdout(http.TraceAll).
-			InsecureSkipVerify(true).
 			R(context.Background()).
-			Header("Host", uri.Host).
-			Get(uriIP.String())
+			Header("Host", hostOverride).
+			Get(server.URL + "/headers")
 		if err != nil {
-			t.Error(err)
+			t.Fatal(err)
 		}
 
-		var headers map[string]any
-		if body, err := resp.AsJSON(); err != nil {
-			t.Error(err)
-		} else {
-			headers = body["headers"].(map[string]any)
+		body, err := resp.AsJSON()
+		if err != nil {
+			t.Fatal(err)
 		}
+		headers := body["headers"].(map[string]any)
 
-		if headers["Host"] != uri.Host {
-			t.Errorf("Expected response headers %s", headers)
+		if headers["Host"] != hostOverride {
+			t.Errorf("expected Host header %q, got %v", hostOverride, headers["Host"])
 		}
 	})
 
 	t.Run("No Auth", func(t *testing.T) {
-		resp, err := http.NewClient().R(context.Background()).Header("Hello", "World").Get("https://httpbin.org/headers")
+		server := startHeadersServer(t)
+
+		resp, err := http.NewClient().R(context.Background()).Header("Hello", "World").Get(server.URL + "/headers")
 		if err != nil {
-			t.Error(err)
+			t.Fatal(err)
 		}
-		var headers map[string]any
-		if body, err := resp.AsJSON(); err != nil {
-			t.Error(err)
-		} else {
-			headers = body["headers"].(map[string]any)
+
+		body, err := resp.AsJSON()
+		if err != nil {
+			t.Fatal(err)
 		}
+		headers := body["headers"].(map[string]any)
+
 		if headers["Hello"] != "World" {
-			t.Errorf("Expected response headers %s", headers)
+			t.Errorf("expected Hello header %q, got %v", "World", headers["Hello"])
 		}
 		if v, ok := headers["Authorization"]; ok {
-			t.Errorf("Expecting blank authentication got %s", v)
+			t.Errorf("expected no Authorization header, got %v", v)
 		}
 	})
 
@@ -293,6 +290,26 @@ func TestQueryParamsPreserveRawKeys(t *testing.T) {
 	}
 }
 
+// startHeadersServer mimics httpbin.org's /headers endpoint, echoing the
+// request headers (and the resolved Host) back as JSON. This keeps the
+// header-handling tests off the unreliable external httpbin.org service.
+func startHeadersServer(t *testing.T) *httptest.Server {
+	t.Helper()
+
+	server := httptest.NewServer(netHTTP.HandlerFunc(func(w netHTTP.ResponseWriter, r *netHTTP.Request) {
+		headers := map[string]string{"Host": r.Host}
+		for key, values := range r.Header {
+			headers[key] = strings.Join(values, ",")
+		}
+
+		w.Header().Set("Content-Type", "application/json")
+		_ = json.NewEncoder(w).Encode(map[string]any{"headers": headers})
+	}))
+	t.Cleanup(server.Close)
+
+	return server
+}
+
 // nolint:unused
 func loggerMiddlware(next netHTTP.RoundTripper) netHTTP.RoundTripper {
 	x := func(req *netHTTP.Request) (*netHTTP.Response, error) {