pw_fuzzer: Expand FuzzTest stubs

This CL adds fake versions of the various FuzzTest domains. These
versions do not do anything except provide compile-time type-checking
that FUZZ_TEST invocations and custom domains should build.

Change-Id: Ic1cd1aa329f0ad22fe8b5ec105e8d209302f849b
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/148334
Reviewed-by: Taylor Cramer <cramertj@google.com>
Presubmit-Verified: CQ Bot Account <pigweed-scoped@luci-project-accounts.iam.gserviceaccount.com>
Commit-Queue: Aaron Green <aarongreen@google.com>

pw_fuzzer/BUILD.bazel

@@ -38,14 +38,34 @@ config_setting(
 pw_cc_library(
     name = "fuzztest",
     testonly = True,
-    deps = ["@pigweed_config//:pw_fuzzer_fuzztest_backend"],
+    hdrs = ["public/pw_fuzzer/fuzztest.h"] + select({
+        ":use_fuzztest": ["private/pw_fuzzer/internal/fuzztest.h"],
+        "//conditions:default": [],
+    }),
+    includes = ["public"] + select({
+        ":use_fuzztest": ["private"],
+        "//conditions:default": [],
+    }),
+    deps = [
+        "//pw_containers",
+        "//pw_result",
+        "//pw_status",
+        "//pw_string",
+        "@pigweed_config//:pw_fuzzer_fuzztest_backend",
+    ],
 )
 
 pw_cc_library(
     name = "fuzztest_stub",
     testonly = True,
-    hdrs = ["public_overrides/fuzztest/fuzztest.h"],
-    includes = ["public_overrides"],
+    hdrs = [
+        "private_overrides/pw_fuzzer/internal/fuzztest.h",
+        "public_overrides/fuzztest/fuzztest.h",
+    ],
+    includes = [
+        "private_overrides",
+        "public_overrides",
+    ],
     deps = ["//pw_unit_test"],
 )
 

pw_fuzzer/BUILD.gn

@@ -20,6 +20,24 @@ import("$dir_pw_docgen/docs.gni")
 import("$dir_pw_third_party/fuzztest/fuzztest.gni")
 import("$dir_pw_unit_test/test.gni")
 
+config("public_include_path") {
+  include_dirs = [ "public" ]
+  visibility = [ ":*" ]
+}
+
+config("private_include_path") {
+  include_dirs = [ "private" ]
+  visibility = [ ":*" ]
+}
+
+config("overrides_include_path") {
+  include_dirs = [
+    "public_overrides",
+    "private_overrides",
+  ]
+  visibility = [ ":*" ]
+}
+
 # See https://llvm.org/docs/LibFuzzer.html#fuzzer-friendly-build-mode
 config("fuzzing_build_mode_unsafe_for_production") {
   defines = [ "FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION" ]
@@ -57,22 +75,37 @@ pw_test_group("tests") {
 #
 # Create FuzzTest-style fuzzers by adding a dep on dir_pw_fuzzer:fuzztest
 
-config("public_overrides_include_path") {
-  include_dirs = [ "public_overrides" ]
-}
-
 # Unit tests with a dep on this target can include FuzzTest-style fuzzers.
 pw_source_set("fuzztest") {
+  # Include headers that extend FuzzTest's interface with support for common
+  # Pigweed types.
+  public = [ "public/pw_fuzzer/fuzztest.h" ]
+  public_configs = [ ":public_include_path" ]
+  public_deps = [
+    dir_pw_containers,
+    dir_pw_result,
+    dir_pw_status,
+    dir_pw_string,
+  ]
   if (dir_pw_third_party_fuzztest != "" && pw_toolchain_FUZZING_ENABLED) {
-    public_deps = [ "$dir_pw_third_party/fuzztest/fuzztest" ]
-    public_configs = [
+    # Include headers and deps that provide a Pigweed-compatible subset of
+    # FuzzTest.
+    public += [ "private/pw_fuzzer/internal/fuzztest.h" ]
+    public_configs += [
       "$dir_pw_third_party/abseil-cpp/configs:disabled_warnings",
       "$dir_pw_third_party/re2/configs:disabled_warnings",
       "$dir_pw_third_party/fuzztest/configs:disabled_warnings",
+      ":private_include_path",
     ]
+    public_deps += [ "$dir_pw_third_party/fuzztest/fuzztest" ]
   } else {
-    public = [ "public_overrides/fuzztest/fuzztest.h" ]
-    public_configs = [ ":public_overrides_include_path" ]
+    # Include headers that provide stubs of the Pigweed-compatible subset of
+    # FuzzTest's interface.
+    public += [
+      "private_overrides/pw_fuzzer/internal/fuzztest.h",
+      "public_overrides/fuzztest/fuzztest.h",
+    ]
+    public_configs += [ ":overrides_include_path" ]
   }
 }
 
@@ -141,11 +174,6 @@ config("libfuzzer_config") {
   }
 }
 
-config("public_include_path") {
-  include_dirs = [ "public" ]
-  visibility = [ ":*" ]
-}
-
 # Includes wrapper's for LLVM's libFuzzer compiler runtime library.
 pw_source_set("libfuzzer") {
   public = [

pw_fuzzer/CMakeLists.txt

@@ -24,15 +24,33 @@ include($ENV{PW_ROOT}/pw_build/pigweed.cmake)
 # converts invocations of `FUZZ_TEST` to disabled empty unit tests.
 if(pw_unit_test_GOOGLETEST_BACKEND STREQUAL "pw_third_party.fuzztest")
   pw_add_library(pw_fuzzer.fuzztest INTERFACE
+    HEADERS
+      public/pw_fuzzer/fuzztest.h
+      private/pw_fuzzer/internal/fuzztest.h
     PUBLIC_DEPS
+      pw_containers
+      pw_result
+      pw_status
+      pw_string
       pw_third_party.fuzztest
+    PUBLIC_INCLUDES
+      public
+      private
   )
 else()
   pw_add_library(pw_fuzzer.fuzztest INTERFACE
     HEADERS
       public_overrides/fuzztest/fuzztest.h
+      private_overrides/pw_fuzzer/internal/fuzztest.h
+    PUBLIC_DEPS
+      pw_containers
+      pw_result
+      pw_status
+      pw_string
     PUBLIC_INCLUDES
+      public
       public_overrides
+      private_overrides
   )
 endif()
 

pw_fuzzer/private/pw_fuzzer/internal/fuzztest.h

@@ -0,0 +1,25 @@
+// Copyright 2023 The Pigweed Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License"); you may not
+// use this file except in compliance with the License. You may obtain a copy of
+// the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+// License for the specific language governing permissions and limitations under
+// the License.
+#pragma once
+
+/// @file fuzztest.h
+/// Replaceable interface to FuzzTest
+///
+/// @rst
+/// When FuzzTest is enabled, this header includes the FuzzTest interface. It
+/// exists only so that it can be replaced by stubs when FuzzTest is *not*
+/// enabled.
+/// @endrst
+
+#include "fuzztest/fuzztest.h"