Add test for HttpValidationPolicy::disallow_multiple_content_length.

PiperOrigin-RevId: 555225274

quiche/balsa/balsa_frame_test.cc

diff --git a/quiche/balsa/balsa_frame_test.cc b/quiche/balsa/balsa_frame_test.cc
index 919051f..4452ecb 100644
--- a/quiche/balsa/balsa_frame_test.cc
+++ b/quiche/balsa/balsa_frame_test.cc
@@ -3146,7 +3146,7 @@
   EXPECT_TRUE(balsa_frame_.MessageFullyRead());
 }
 
-TEST_F(HTTPBalsaFrameTest, TwoDifferentContentHeadersIsAnError) {
+TEST_F(HTTPBalsaFrameTest, TwoDifferentContentLengthHeadersIsAnError) {
   std::string header =
       "HTTP/1.1 200 OK\r\n"
       "content-length: 12\r\n"
@@ -3159,7 +3159,7 @@
             balsa_frame_.ErrorCode());
 }
 
-TEST_F(HTTPBalsaFrameTest, TwoSameContentHeadersIsNotAnError) {
+TEST_F(HTTPBalsaFrameTest, TwoSameContentLengthHeadersIsNotAnError) {
   std::string header =
       "POST / HTTP/1.1\r\n"
       "content-length: 1\r\n"
@@ -3175,6 +3175,23 @@
   EXPECT_TRUE(balsa_frame_.MessageFullyRead());
 }
 
+TEST_F(HTTPBalsaFrameTest, TwoSameContentLengthHeadersIsAnError) {
+  HttpValidationPolicy http_validation_policy;
+  http_validation_policy.disallow_multiple_content_length = true;
+  balsa_frame_.set_http_validation_policy(http_validation_policy);
+
+  std::string header =
+      "POST / HTTP/1.1\r\n"
+      "content-length: 1\r\n"
+      "content-length: 1\r\n"
+      "\r\n"
+      "1";
+  balsa_frame_.ProcessInput(header.data(), header.size());
+  EXPECT_TRUE(balsa_frame_.Error());
+  EXPECT_EQ(BalsaFrameEnums::MULTIPLE_CONTENT_LENGTH_KEYS,
+            balsa_frame_.ErrorCode());
+}
+
 TEST_F(HTTPBalsaFrameTest, TwoTransferEncodingHeadersIsAnError) {
   std::string header =
       "HTTP/1.1 200 OK\r\n"