Add benchmark for catch_test_macros.hpp inclusion

Author: horenmar

benchmarks/CMakeLists.txt

@@ -9,8 +9,13 @@ add_executable(AssertionsSlowPath
   assertion_listener.cpp
 )
 
+add_executable(EmptyExecutable
+  only_include.cpp
+)
+
 target_link_libraries(AssertionsFastPath PRIVATE Catch2::Catch2WithMain)
 target_link_libraries(AssertionsSlowPath PRIVATE Catch2::Catch2WithMain)
+target_link_libraries(EmptyExecutable PRIVATE Catch2::Catch2WithMain)
 
-list(APPEND CATCH_TEST_TARGETS AssertionsFastPath AssertionsSlowPath)
+list(APPEND CATCH_TEST_TARGETS AssertionsFastPath AssertionsSlowPath EmptyExecutable)
 set(CATCH_TEST_TARGETS ${CATCH_TEST_TARGETS} PARENT_SCOPE)

benchmarks/only_include.cpp

@@ -0,0 +1,16 @@
+
+//              Copyright Catch2 Authors
+// Distributed under the Boost Software License, Version 1.0.
+//   (See accompanying file LICENSE.txt or copy at
+//        https://www.boost.org/LICENSE_1_0.txt)
+
+// SPDX-License-Identifier: BSL-1.0
+
+/**\file 
+ * "empty" include of catch_test_macros.hpp
+ * 
+ * This file does only one thing: include `catch2/catch_test_macros.hpp`,
+ * so that we can measure the compilation cost of the header.
+ */
+
+#include <catch2/catch_test_macros.hpp>

benchmarks/readme.md

@@ -49,7 +49,7 @@ hyperfine --warmup 2 --shell none --parameter-list version old,new '/home/xarn/b
 ```
 
 **Compare performance of `REQUIRE` with stringification enabled, release build**
-```
+```text
 hyperfine --warmup 2 --shell none --parameter-list version old,new '/home/xarn/benches/Catch2-{version}/build-release/benchmarks/AssertionsFastPath -s -o /dev/null "REQUIRE"'
 ```
 _Note that we redirect the output to `/dev/null` to reduce the overhead of the actual output printing, to see just the impact of stringification._
@@ -60,8 +60,18 @@ _Note that we redirect the output to `/dev/null` to reduce the overhead of the a
 As tests are often iterated upon and relinked, the compilation cost of
 Catch2 is also important.
 
+
+### Examples
+
+**Compare overhead of including `catch_test_macros.hpp`**
+```text
+hyperfine --warmup 2 --shell none --parameter-list version old,new '/usr/bin/c++  -I/home/xarn/benches/Catch2-{version}/src/catch2/.. -I/home/xarn/benches/Catch2-{version}/build-debug/generated-includes -g -o /dev/null -c /home/xarn/benches/Catch2-{version}/benchmarks/only_include.cpp'
+```
+
+**Compare build time of Catch2's `SelfTest` test suite, Debug build**
+```text
+hyperfine --warmup 2 --parameter-list version old,vas --prepare 'find ~/benches/Catch2-{version}/tests/SelfTest -type f -name "*.cpp" -exec touch {} +' 'ninja -j 1 -C ~/benches/Catch2-{version}/build-debug'
+```
+
 TODO:
-  * Single file vs test suite build
-  * Practical examples
-  * Include-only overhead
-  * Link-only example
+  * Link-only recipe