From ff8bde59a8fb9a2ad2538016ac0d3cecd0ca57da Mon Sep 17 00:00:00 2001
From: Tobias Hienzsch <post@tobias-hienzsch.de>
Date: Fri, 22 May 2020 08:06:50 +0200
Subject: [PATCH] unittest: Update catch2 section

---
 chapters/testing/unit_test.md | 95 +++++++++++++++++++++++++++++++++--
 1 file changed, 91 insertions(+), 4 deletions(-)

diff --git a/chapters/testing/unit_test.md b/chapters/testing/unit_test.md
index b97c941..997b9e4 100644
--- a/chapters/testing/unit_test.md
+++ b/chapters/testing/unit_test.md
@@ -2,11 +2,98 @@
 
 ## Catch2
 
-[github.com/catchorg/Catch2](https://github.com/catchorg/Catch2)
+- [github.com/catchorg/Catch2](https://github.com/catchorg/Catch2)
+- [Example Project: tobanteAudio/juce-6-demo](https://github.com/tobanteAudio/juce-6-demo)
 
-- Link against CMake shared code target
-- Register tests
-- CTest
+### Include Catch2
+
+```cmake
+option(YOURPLUGIN_BUILD_TESTS "Build the unit tests with Catch2" ON)
+
+if(YOURPLUGIN_BUILD_TESTS)
+    list (APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/3rd_party/Catch2/contrib")
+    enable_testing()
+    add_subdirectory(3rd_party/Catch2 EXCLUDE_FROM_ALL)
+    include(CTest)
+    include(Catch)
+endif()
+```
+
+### Write Test
+
+#### main
+
+We need to write a custom main for Catch, since we need to initialize & shutdown JUCE.
+
+```cpp
+#include "JuceHeader.h"
+
+#define CATCH_CONFIG_RUNNER
+#include "catch2/catch.hpp"
+
+int main(int argc, char* argv[])
+{
+    juce::initialiseJuce_GUI();
+    int result = Catch::Session().run(argc, argv);
+    juce::shutdownJuce_GUI();
+    return result;
+}
+```
+
+#### processor
+
+Simple tests checking the plug-in name & if a mono bus layout is supported.
+
+```cpp
+#include "catch2/catch.hpp"
+
+#include "YourProcessor.hpp"
+
+TEST_CASE("processor: Name", "[processor]")
+{
+    auto processor = YourProcessor {};
+    REQUIRE(processor.getName() == juce::String {"Plugin Name"});
+}
+
+
+TEST_CASE("processor: BusesLayoutSupportMono", "[processor]")
+{
+    auto processor     = YourProcessor {};
+    auto layout        = juce::AudioProcessor::BusesLayout {};
+    layout.inputBuses  = juce::AudioChannelSet::mono();
+    layout.outputBuses = juce::AudioChannelSet::mono();
+
+    REQUIRE(processor.isBusesLayoutSupported(layout));
+}
+
+```
+
+### Link against SharedCode
+
+Link the unit test target to the shared code of your plug-in.
+
+```cmake
+juce_add_plugin(YourPlugin ...)
+
+# ...
+
+if(YOURPLUGIN_BUILD_TESTS)
+    add_executable(YourPlugin_Tests)
+    target_sources(YourPlugin_Tests PRIVATE Source/main_test.cpp)
+    catch_discover_tests(YourPlugin_Tests)
+    target_link_libraries(YourPlugin_Tests PRIVATE YourPlugin Catch2::Catch2)
+endif()
+```
+
+### CTest
+
+After building run `ctest` inside your build directory.
+
+```sh
+cd $CMAKE_BUILD_DIR
+ctest -C Release # Release build
+ctest -C Debug   # Debug build
+```
 
 ## JUCE Unit Tests