Improve formatting of Error Logs related to CHIP_ERROR in GoogleTest

build/chip/tests.gni

@@ -26,6 +26,10 @@ declare_args() {
 declare_args() {
   # Enable building tests.
   chip_build_tests = current_os != "freertos"
+
+  # Enabling useful support functions when building using GoogleTest framework (used in unit tests and pw_fuzzer FuzzTests)
+  # For unit tests: this should only be enabled through build_examples.py, see PR #36268
+  chip_build_tests_googletest = false
 }
 
 declare_args() {

build/toolchain/pw_fuzzer/BUILD.gn

@@ -64,6 +64,9 @@ gcc_toolchain("chip_pw_fuzztest") {
     dir_pw_third_party_fuzztest = "//third_party/fuzztest"
     dir_pw_third_party_googletest = "$dir_googletest"
 
+    # Since pw_fuzzer uses GoogleTest, activating this allows us to benefit from supporting functions
+    chip_build_tests_googletest = true
+
     # TODO: Seems that re2 support within FuzzTest was deprecated, keeping it defined is triggering warning
     # Remove if re2 is indeed not needed
     # dir_pw_third_party_re2 = "//third_party/re2/src"

scripts/build/builders/host.py

@@ -502,6 +502,7 @@ def __init__(self, root, runner, app: HostApp, board=HostBoard.NATIVE,
             self.extra_gn_options.append('import("//build_overrides/googletest.gni")')
             self.extra_gn_options.append('pw_unit_test_BACKEND="$dir_pw_unit_test:googletest"')
             self.extra_gn_options.append('dir_pw_third_party_googletest="$dir_googletest"')
+            self.extra_gn_options.append('chip_build_tests_googletest=true')
 
     def GnBuildArgs(self):
         if self.board == HostBoard.NATIVE:

src/lib/core/BUILD.gn

@@ -71,6 +71,7 @@ buildconfig_header("chip_buildconfig") {
     "CHIP_CONFIG_TLV_VALIDATE_CHAR_STRING_ON_WRITE=${chip_tlv_validate_char_string_on_write}",
     "CHIP_CONFIG_TLV_VALIDATE_CHAR_STRING_ON_READ=${chip_tlv_validate_char_string_on_read}",
     "CHIP_CONFIG_COMMAND_SENDER_BUILTIN_SUPPORT_FOR_BATCHED_COMMANDS=${chip_enable_sending_batch_commands}",
+    "CHIP_CONFIG_TEST_GOOGLETEST=${chip_build_tests_googletest}",
   ]
 
   visibility = [ ":chip_config_header" ]
@@ -116,6 +117,7 @@ source_set("string-builder-adapters") {
   public_deps = [
     ":error",
     "$dir_pw_string",
+    "$dir_pw_unit_test",
   ]
 }
 

src/lib/core/CHIPConfig.h

@@ -1845,6 +1845,17 @@ extern const char CHIP_NON_PRODUCTION_MARKER[];
 #define CHIP_CONFIG_MAX_BDX_LOG_TRANSFERS 5
 #endif // CHIP_CONFIG_MAX_BDX_LOG_TRANSFERS
 
+/**
+ *  @def CHIP_CONFIG_TEST_GOOGLETEST
+ *
+ *  @brief
+ *    If asserted (1), enable APIs that support unit tests built with the GoogleTest framework
+ *
+ */
+#ifndef CHIP_CONFIG_TEST_GOOGLETEST
+#define CHIP_CONFIG_TEST_GOOGLETEST 0
+#endif // CHIP_CONFIG_TEST_GOOGLETEST
+
 /**
  * @}
  */

src/lib/core/StringBuilderAdapters.cpp

@@ -29,3 +29,18 @@ StatusWithSize ToString<CHIP_ERROR>(const CHIP_ERROR & err, pw::span<char> buffe
 }
 
 } // namespace pw
+
+#if CHIP_CONFIG_TEST_GOOGLETEST
+namespace chip {
+
+void PrintTo(const CHIP_ERROR & err, std::ostream * os)
+{
+    if (CHIP_ERROR::IsSuccess(err))
+    {
+        *os << "CHIP_NO_ERROR";
+        return;
+    }
+    *os << "CHIP_ERROR:<" << err.Format() << ">";
+}
+} // namespace chip
+#endif // CHIP_CONFIG_TEST_GOOGLETEST

src/lib/core/StringBuilderAdapters.h

@@ -42,6 +42,7 @@
 ///    Actual: CHIP_ERROR:<src/lib/core/TLVReader.cpp:889: Error 0x00000022> == CHIP_NO_ERROR
 
 #include <pw_string/string_builder.h>
+#include <pw_unit_test/framework.h>
 
 #include <lib/core/CHIPError.h>
 
@@ -51,3 +52,22 @@ template <>
 StatusWithSize ToString<CHIP_ERROR>(const CHIP_ERROR & err, pw::span<char> buffer);
 
 } // namespace pw
+#if CHIP_CONFIG_TEST_GOOGLETEST
+
+namespace chip {
+
+/// The following function is for usage with GoogleTest.
+/// This implementation of PrintTo allows GoogleTest to print CHIP_ERROR for better logs in the event of a failure.
+/// Example output with PrintTo():
+///
+///   src/lib/core/tests/TestTLV.cpp:382: Failure
+///   Expected equality of these values:
+///           err
+///             Which is: CHIP_ERROR:<src/lib/core/TLVWriter.cpp:674: Error 0x00000024>
+///           CHIP_ERROR(0, "src/lib/core/tests/TestTLV.cpp", 382)
+///             Which is: CHIP_NO_ERROR
+///
+/// This enhances the readability and diagnostic information in GoogleTest test logs.
+void PrintTo(const CHIP_ERROR & err, std::ostream * os);
+} // namespace chip
+#endif // CHIP_CONFIG_TEST_GOOGLETEST