From 4c1493744bb02a8b4fad7c3211aa551fcd4d3e15 Mon Sep 17 00:00:00 2001
From: "google-labs-jules[bot]"
 <161369871+google-labs-jules[bot]@users.noreply.github.com>
Date: Wed, 1 Jul 2026 14:44:29 +0000
Subject: [PATCH] Add request body size limit error test in routeAuthAndBody

Added `TestHandler_bodyTooLarge_returns400` in `internal/refbackend/gemini/server_test.go` to cover the `http.StatusBadRequest` path in `routeAuthAndBody` when a request body exceeds the 10MB `maxBodyBytes` limit.

Co-authored-by: matdev83 <211248003+matdev83@users.noreply.github.com>
---
 internal/refbackend/gemini/server_test.go | 32 +++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/internal/refbackend/gemini/server_test.go b/internal/refbackend/gemini/server_test.go
index 056c2f31..182e8796 100644
--- a/internal/refbackend/gemini/server_test.go
+++ b/internal/refbackend/gemini/server_test.go
@@ -1,6 +1,7 @@
 package gemini_test
 
 import (
+	"bytes"
 	"context"
 	"encoding/base64"
 	"io"
@@ -336,3 +337,34 @@ func TestHandler_forced429_streamPath_returnsJSONError(t *testing.T) {
 		t.Fatalf("Content-Type: %q", ct)
 	}
 }
+
+func TestHandler_bodyTooLarge_returns400(t *testing.T) {
+	t.Parallel()
+	srv := httptest.NewServer(refbackend.NewHandler(refbackend.Config{
+		AllowMissingAPIKey: true,
+	}))
+	t.Cleanup(srv.Close)
+
+	// maxBodyBytes is 10 MB, so send 10 MB + 1 byte
+	body := bytes.NewReader(make([]byte, 10<<20+1))
+	req, err := http.NewRequest(http.MethodPost, srv.URL+geminiGenerateMinimalPath, body)
+	if err != nil {
+		t.Fatal(err)
+	}
+	req.Header.Set("Content-Type", "application/json")
+
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer func() { _ = resp.Body.Close() }()
+
+	if resp.StatusCode != http.StatusBadRequest {
+		t.Fatalf("status: got %d, want %d", resp.StatusCode, http.StatusBadRequest)
+	}
+
+	b, _ := io.ReadAll(resp.Body)
+	if !strings.Contains(string(b), "read body") {
+		t.Fatalf("body: %s", b)
+	}
+}