Add final missing test

Author: kstribrnAmzn

test/unit-test/core_http_send_utest.c

@@ -445,6 +445,34 @@ static llhttp_errno_t llhttp_execute_error( llhttp_t * pParser,
     return httpParsingErrno;
 }
 
+/* Mocked llhttp_execute callback that parses the status line, then invokes
+ * on_header_field with a zero-length field name to exercise the early return
+ * guard in httpParserOnHeaderFieldCallback. */
+static llhttp_errno_t llhttp_execute_zero_length_header_field( llhttp_t * pParser,
+                                                               const char * pData,
+                                                               size_t len,
+                                                               int cmock_num_calls )
+{
+    ( void ) cmock_num_calls;
+    ( void ) len;
+    const char * pNext = pData;
+    llhttp_settings_t * pSettings = ( llhttp_settings_t * ) pParser->settings;
+    int cbReturnValue = 0;
+
+    pSettings->on_message_begin( pParser );
+    helper_parse_status_line( &pNext, pParser, pSettings );
+
+    /* Invoke on_header_field with length zero. The real callback should return
+     * LLHTTP_STOP_PARSING. */
+    cbReturnValue = pSettings->on_header_field( pParser, pNext, 0 );
+    TEST_ASSERT_EQUAL( LLHTTP_STOP_PARSING, cbReturnValue );
+
+    pParser->error = HPE_USER;
+    httpParserExecuteCallCount++;
+    return HPE_USER;
+}
+
+
 /* Mock helper that parses the status line starting from pNext. */
 static void helper_parse_status_line( const char ** pNext,
                                       llhttp_t * pParser,
@@ -1960,3 +1988,23 @@ void test_HTTPClient_Send_parsing_errors( void )
                                     0 );
     TEST_ASSERT_EQUAL( HTTPParserInternalError, returnStatus );
 }
+
+/* Test that httpParserOnHeaderFieldCallback returns LLHTTP_STOP_PARSING when
+ * the parser invokes it with a zero-length header field name (lines 720-724
+ * of core_http_client.c). */
+void test_HTTPClient_Send_zero_length_header_field( void )
+{
+    HTTPStatus_t returnStatus = HTTPSuccess;
+
+    llhttp_execute_Stub( llhttp_execute_zero_length_header_field );
+
+    returnStatus = HTTPClient_Send( &transportInterface,
+                                    &requestHeaders,
+                                    NULL,
+                                    0,
+                                    &response,
+                                    0 );
+    /* HPE_USER falls through to the default case in processLlhttpError,
+     * which maps to HTTPParserInternalError. */
+    TEST_ASSERT_EQUAL( HTTPParserInternalError, returnStatus );
+}