Improve ext_proc code coverage

source/extensions/filters/http/ext_proc/ext_proc.h

@@ -490,6 +490,7 @@ class FilterConfigPerRoute : public Router::RouteSpecificFilterConfig {
 class Filter : public Logger::Loggable<Logger::Id::ext_proc>,
                public Http::PassThroughFilter,
                public ExternalProcessorCallbacks {
+  friend class FilterAccessor;
   // The result of an attempt to open the stream
   enum class StreamOpenState {
     // The stream was opened successfully

source/extensions/filters/http/ext_proc/matching_utils.h

@@ -13,6 +13,8 @@ namespace HttpFilters {
 namespace ExternalProcessing {
 
 class ExpressionManager : public Logger::Loggable<Logger::Id::ext_proc> {
+  friend class ExpressionManagerTestAccessor;
+
 public:
   using CelExpression = Filters::Common::Expr::CompiledExpression;
 

source/extensions/filters/network/ext_proc/ext_proc.h

@@ -182,6 +182,8 @@ class MessageTimeoutManager : public Logger::Loggable<Logger::Id::ext_proc> {
 class NetworkExtProcFilter : public Envoy::Network::Filter,
                              ExternalProcessorCallbacks,
                              Envoy::Logger::Loggable<Envoy::Logger::Id::ext_proc> {
+  friend class NetworkExtProcFilterAccessor;
+
 public:
   // The result of an attempt to open the stream
   enum class StreamOpenState {

test/coverage.yaml

@@ -36,14 +36,16 @@ directories:
   source/extensions/common/wasm/ext: 100.0
   source/extensions/clusters/dynamic_modules: 97.7
   source/extensions/filters/common: 97.1
+  source/extensions/filters/common/ext_proc: 98.0
   source/extensions/filters/common/fault: 94.5
   source/extensions/filters/common/lua: 95.6
   source/extensions/filters/http/a2a: 98.4
   source/extensions/filters/http/cache: 95.9
   source/extensions/filters/http/dynamic_forward_proxy: 94.8
   source/extensions/filters/http/dynamic_modules: 95.5
   source/extensions/filters/http/decompressor: 95.9
-  source/extensions/filters/http/ext_proc: 96.5
+  source/extensions/filters/http/ext_proc: 98.0
+  source/extensions/filters/http/ext_proc/http_client: 100.0
   source/extensions/filters/http/grpc_json_reverse_transcoder: 94.9
   source/extensions/filters/http/grpc_json_transcoder: 94.1  # TODO(#28232)
   source/extensions/filters/http/ip_tagging: 95.9
@@ -56,6 +58,7 @@ directories:
   source/extensions/filters/listener/original_src: 92.1
   source/extensions/filters/listener/tls_inspector: 94.5
   source/extensions/filters/network/dubbo_proxy: 96.2
+  source/extensions/filters/network/ext_proc: 98.0
   source/extensions/filters/network/mongo_proxy: 96.1
   source/extensions/filters/network/reverse_tunnel: 95.9
   source/extensions/filters/network/sni_cluster: 88.9
@@ -88,6 +91,8 @@ directories:
   source/extensions/health_checkers: 96.1
   source/extensions/health_checkers/http: 94.6
   source/extensions/health_checkers/grpc: 92.3
+  source/extensions/http/ext_proc/processing_request_modifiers/mapped_attribute_builder: 98.0
+  source/extensions/http/ext_proc/response_processors/save_processing_response: 98.0
   source/extensions/config_subscription/rest: 94.9
   source/extensions/matching/input_matchers/cel_matcher: 100.0
   source/extensions/dynamic_modules/sdk/cpp: 0.0  # SDK code self not directly tested

test/extensions/filters/http/ext_proc/BUILD

@@ -345,6 +345,33 @@ envoy_extension_cc_test(
     ],
 )
 
+envoy_extension_cc_test(
+    name = "save_processing_response_test",
+    size = "small",
+    srcs = ["save_processing_response_test.cc"],
+    extension_names = ["envoy.filters.http.ext_proc"],
+    rbe_pool = "6gig",
+    tags = ["skip_on_windows"],
+    deps = [
+        "//source/extensions/http/ext_proc/response_processors/save_processing_response:save_processing_response_lib",
+        "//test/mocks/stream_info:stream_info_mocks",
+        "//test/test_common:utility_lib",
+    ],
+)
+
+envoy_extension_cc_test(
+    name = "logging_info_test",
+    size = "small",
+    srcs = ["logging_info_test.cc"],
+    extension_names = ["envoy.filters.http.ext_proc"],
+    rbe_pool = "6gig",
+    tags = ["skip_on_windows"],
+    deps = [
+        "//source/extensions/filters/http/ext_proc",
+        "//test/test_common:utility_lib",
+    ],
+)
+
 envoy_extension_cc_test(
     name = "mutation_utils_test",
     size = "small",

test/extensions/filters/http/ext_proc/filter_local_reply_streaming_test.cc

@@ -1329,6 +1329,58 @@ TEST_F(StreamingLocalReplyTest, SaveStreamingLocalResponse) {
   filter_->onDestroy();
 }
 
+TEST_F(StreamingLocalReplyTest, StartLocalResponseInvalidHeaders) {
+  initialize(R"EOF(
+  grpc_service:
+    envoy_grpc:
+      cluster_name: "ext_proc_server"
+  )EOF");
+
+  EXPECT_EQ(FilterHeadersStatus::StopIteration, filter_->decodeHeaders(request_headers_, false));
+
+  auto response = std::make_unique<ProcessingResponse>();
+  auto* headers_response =
+      response->mutable_streamed_immediate_response()->mutable_headers_response();
+  auto* h = headers_response->mutable_headers()->add_headers();
+  h->set_key(":status");
+  h->set_raw_value(std::string(1, '\0')); // Invalid header value
+
+  EXPECT_CALL(encoder_callbacks_, sendLocalReply(Http::Code::InternalServerError, _, _, _, _));
+  stream_callbacks_->onReceiveMessage(std::move(response));
+}
+
+TEST_F(StreamingLocalReplyTest, ProcessLocalTrailersInvalid) {
+  initialize(R"EOF(
+  grpc_service:
+    envoy_grpc:
+      cluster_name: "ext_proc_server"
+  )EOF");
+
+  EXPECT_EQ(FilterHeadersStatus::StopIteration, filter_->decodeHeaders(request_headers_, true));
+
+  // Start local response
+  auto response1 = std::make_unique<ProcessingResponse>();
+  auto* headers_response =
+      response1->mutable_streamed_immediate_response()->mutable_headers_response();
+  auto* h1 = headers_response->mutable_headers()->add_headers();
+  h1->set_key(":status");
+  h1->set_raw_value("200");
+  headers_response->set_end_of_stream(false);
+
+  stream_callbacks_->onReceiveMessage(std::move(response1));
+
+  // Send invalid trailers
+  auto response2 = std::make_unique<ProcessingResponse>();
+  auto* trailers_response =
+      response2->mutable_streamed_immediate_response()->mutable_trailers_response();
+  auto* h2 = trailers_response->add_headers();
+  h2->set_key("invalid name");
+  h2->set_raw_value("value");
+
+  EXPECT_CALL(encoder_callbacks_, sendLocalReply(Http::Code::InternalServerError, _, _, _, _));
+  stream_callbacks_->onReceiveMessage(std::move(response2));
+}
+
 } // namespace
 } // namespace ExternalProcessing
 } // namespace HttpFilters