# 4.2 使用Catch2库进行单元测试 **NOTE**:*此示例代码可以在* *中找到，包含一个C++的示例。该示例在CMake 3.5版(或更高版本)中是有效的，并且已经在GNU/Linux、macOS和Windows上进行过测试。* 前面的配置中，使用返回码来表示`test.cpp`测试的成功或失败。对于简单功能没问题，但是通常情况下，我们想要使用一个测试框架，它提供了相关基础设施来运行更复杂的测试，包括固定方式进行测试，与数值公差的比较，以及在测试失败时输出更好的错误报告。这里，我们用目前比较流行的测试库Catch2( )来进行演示。这个测试框架有个很好的特性，它可以通过单个头库包含在项目中进行测试，这使得编译和更新框架特别容易。这个配置中，我们将CMake和Catch2结合使用，来测试上一个求和代码。 我们需要`catch.hpp`头文件，可以从 (我们使用的是版本2.0.1)下载，并将它与`test.cpp`一起放在项目的根目录下。 ## 准备工作 `main.cpp`、`sum_integers.cpp`和`sum_integers.hpp`与之前的示例相同，但将更新`test.cpp`: ```cpp #include "sum_integers.hpp" // this tells catch to provide a main() // only do this in one cpp file #define CATCH_CONFIG_MAIN #include "catch.hpp" #include TEST_CASE("Sum of integers for a short vector", "[short]") { auto integers = {1, 2, 3, 4, 5}; REQUIRE(sum_integers(integers) == 15); } TEST_CASE("Sum of integers for a longer vector", "[long]") { std::vector integers; for (int i = 1; i < 1001; ++i) { integers.push_back(i); } REQUIRE(sum_integers(integers) == 500500); } ``` `catch.hpp`头文件可以从 (版本为2.0.1)下载，并将它与`test.cpp`放在项目的根目录中。 ## 具体实施 使用Catch2库，需要修改之前的所使用`CMakeList.txt`： 1. 保持`CMakeLists.txt`大多数部分内容不变: ``` # set minimum cmake version cmake_minimum_required(VERSION 3.5 FATAL_ERROR) # project name and language project(recipe-02 LANGUAGES CXX) # require C++11 set(CMAKE_CXX_STANDARD 11) set(CMAKE_CXX_EXTENSIONS OFF) set(CMAKE_CXX_STANDARD_REQUIRED ON) # example library add_library(sum_integers sum_integers.cpp) # main code add_executable(sum_up main.cpp) target_link_libraries(sum_up sum_integers) # testing binary add_executable(cpp_test test.cpp) target_link_libraries(cpp_test sum_integers) ``` 2. 对于上一个示例的配置，需要保留一个测试，并重命名它。注意，`--success`选项可传递给单元测试的可执行文件。这是一个Catch2选项，测试成功时，也会有输出: ``` enable_testing() add_test( NAME catch_test COMMAND $ --success ) ``` 3. 就是这样！让我们来配置、构建和测试。CTest中，使用`-V`选项运行测试，以获得单元测试可执行文件的输出: ``` $ mkdir -p build $ cd build $ cmake .. $ cmake --build . $ ctest -V UpdateCTestConfiguration from :/home/user/cmake-cookbook/chapter-04/recipe-02/cxx-example/build/DartConfiguration.tcl UpdateCTestConfiguration from :/home/user/cmake-cookbook/chapter-04/recipe-02/cxx-example/build/DartConfiguration.tcl Test project /home/user/cmake-cookbook/chapter-04/recipe-02/cxx-example/build Constructing a list of tests Done constructing a list of tests Updating test list for fixtures Added 0 tests to meet fixture requirements Checking test dependency graph... Checking test dependency graph end test 1 Start 1: catch_test 1: Test command: /home/user/cmake-cookbook/chapter-04/recipe-02/cxx-example/build/cpp_test "--success" 1: Test timeout computed to be: 10000000 1: 1: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1: cpp_test is a Catch v2.0.1 host application. 1: Run with -? for options 1: 1: ---------------------------------------------------------------- 1: Sum of integers for a short vector 1: ---------------------------------------------------------------- 1: /home/user/cmake-cookbook/chapter-04/recipe-02/cxx-example/test.cpp:10 1: ................................................................... 1: 1: /home/user/cmake-cookbook/chapter-04/recipe-02/cxx-example/test.cpp:12: 1: PASSED: 1: REQUIRE( sum_integers(integers) == 15 ) 1: with expansion: 1: 15 == 15 1: 1: ---------------------------------------------------------------- 1: Sum of integers for a longer vector 1: ---------------------------------------------------------------- 1: /home/user/cmake-cookbook/chapter-04/recipe-02/cxx-example/test.cpp:15 1: ................................................................... 1: 1: /home/user/cmake-cookbook/chapter-04/recipe-02/cxx-example/test.cpp:20: 1: PASSED: 1: REQUIRE( sum_integers(integers) == 500500 ) 1: with expansion: 1: 500500 (0x7a314) == 500500 (0x7a314) 1: 1: =================================================================== 1: All tests passed (2 assertions in 2 test cases) 1: 1/1 Test #1: catch_test ....................... Passed 0.00 s 100% tests passed, 0 tests failed out of 1 Total Test time (real) = 0.00 se ``` 4. 我们也可以测试`cpp_test`的二进制文件，可以直接从Catch2中看到输出: ``` $ ./cpp_test --success ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ cpp_test is a Catch v2.0.1 host application. Run with -? for options ------------------------------------------------------------------- Sum of integers for a short vector ------------------------------------------------------------------- /home/user/cmake-cookbook/chapter-04/recipe-02/cxx-example/test.cpp:10 ................................................................... /home/user/cmake-cookbook/chapter-04/recipe-02/cxx-example/test.cpp:12: PASSED: REQUIRE( sum_integers(integers) == 15 ) with expansion: 15 == 15 ------------------------------------------------------------------- Sum of integers for a longer vector ------------------------------------------------------------------- /home/user/cmake-cookbook/chapter-04/recipe-02/cxx-example/test.cpp:15 ................................................................... /home/user/cmake-cookbook/chapter-04/recipe-02/cxx-example/test.cpp:20: PASSED: REQUIRE( sum_integers(integers) == 500500 ) with expansion: 500500 (0x7a314) == 500500 (0x7a314) =================================================================== All tests passed (2 assertions in 2 test cases) ``` 5. Catch2将生成一个可执行文件，还可以尝试执行以下命令，以探索单元测试框架提供的选项: ``` $ ./cpp_test --help ``` ## 工作原理 Catch2是一个单头文件测试框架，所以不需要定义和构建额外的目标。只需要确保CMake能找到`catch.hpp`，从而构建`test.cpp`即可。为了方便起见，将它放在与`test.cpp`相同的目录中，我们可以选择一个不同的位置，并使用`target_include_directory`指示该位置。另一种方法是将头部封装到接口库中，这可以在Catch2文档中说明( ): ``` # Prepare "Catch" library for other executables set(CATCH_INCLUDE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/catch) add_library(Catch INTERFACE) target_include_directories(Catch INTERFACE ${CATCH_INCLUDE_DIR}) ``` 然后，我们对库进行如下链接: ``` target_link_libraries(cpp_test Catch) ``` 回想一下第3中的讨论，在第1章从简单的可执行库到接口库，是CMake提供的伪目标库，这些伪目标库对于指定项目外部目标的需求非常有用。 ## 更多信息 这是一个简单的例子，主要关注CMake。当然，Catch2提供了更多功能。有关Catch2框架的完整文档，可访问 。 Catch2代码库包含有CMake函数，用于解析Catch测试并自动创建CMake测试，不需要显式地输入`add_test()`函数，可见 。 --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. 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