leveldb.project/third_party/googletest/docs/quickstart-cmake.md

# Quickstart: Building with CMake

This tutorial aims to get you up and running with GoogleTest using CMake. If
you're using GoogleTest for the first time or need a refresher, we recommend
this tutorial as a starting point. If your project uses Bazel, see the
[Quickstart for Bazel](quickstart-bazel.md) instead.

## Prerequisites

To complete this tutorial, you'll need:

*   A compatible operating system (e.g. Linux, macOS, Windows).
*   A compatible C++ compiler that supports at least C++11.
*   [CMake](https://cmake.org/) and a compatible build tool for building the
    project.
    *   Compatible build tools include
        [Make](https://www.gnu.org/software/make/),
        [Ninja](https://ninja-build.org/), and others - see
        [CMake Generators](https://cmake.org/cmake/help/latest/manual/cmake-generators.7.html)
        for more information.

See [Supported Platforms](platforms.md) for more information about platforms
compatible with GoogleTest.

If you don't already have CMake installed, see the
[CMake installation guide](https://cmake.org/install).

{: .callout .note}
Note: The terminal commands in this tutorial show a Unix shell prompt, but the
commands work on the Windows command line as well.

## Set up a project

CMake uses a file named `CMakeLists.txt` to configure the build system for a
project. You'll use this file to set up your project and declare a dependency on
GoogleTest.

First, create a directory for your project:

```
$ mkdir my_project && cd my_project
```

Next, you'll create the `CMakeLists.txt` file and declare a dependency on
GoogleTest. There are many ways to express dependencies in the CMake ecosystem;
in this quickstart, you'll use the
[`FetchContent` CMake module](https://cmake.org/cmake/help/latest/module/FetchContent.html).
To do this, in your project directory (`my_project`), create a file named
`CMakeLists.txt` with the following contents:

```cmake
cmake_minimum_required(VERSION 3.14)
project(my_project)

# GoogleTest requires at least C++11
set(CMAKE_CXX_STANDARD 11)

include(FetchContent)
FetchContent_Declare(
  googletest
  URL https://github.com/google/googletest/archive/609281088cfefc76f9d0ce82e1ff6c30cc3591e5.zip
)
# For Windows: Prevent overriding the parent project's compiler/linker settings
set(gtest_force_shared_crt ON CACHE BOOL "" FORCE)
FetchContent_MakeAvailable(googletest)
```

The above configuration declares a dependency on GoogleTest which is downloaded
from GitHub. In the above example, `609281088cfefc76f9d0ce82e1ff6c30cc3591e5` is
the Git commit hash of the GoogleTest version to use; we recommend updating the
hash often to point to the latest version.

For more information about how to create `CMakeLists.txt` files, see the
[CMake Tutorial](https://cmake.org/cmake/help/latest/guide/tutorial/index.html).

## Create and run a binary

With GoogleTest declared as a dependency, you can use GoogleTest code within
your own project.

As an example, create a file named `hello_test.cc` in your `my_project`
directory with the following contents:

```cpp
#include <gtest/gtest.h>

// Demonstrate some basic assertions.
TEST(HelloTest, BasicAssertions) {
  // Expect two strings not to be equal.
  EXPECT_STRNE("hello", "world");
  // Expect equality.
  EXPECT_EQ(7 * 6, 42);
}
```

GoogleTest provides [assertions](primer.md#assertions) that you use to test the
behavior of your code. The above sample includes the main GoogleTest header file
and demonstrates some basic assertions.

To build the code, add the following to the end of your `CMakeLists.txt` file:

```cmake
enable_testing()

add_executable(
  hello_test
  hello_test.cc
)
target_link_libraries(
  hello_test
  gtest_main
)

include(GoogleTest)
gtest_discover_tests(hello_test)
```

The above configuration enables testing in CMake, declares the C++ test binary
you want to build (`hello_test`), and links it to GoogleTest (`gtest_main`). The
last two lines enable CMake's test runner to discover the tests included in the
binary, using the
[`GoogleTest` CMake module](https://cmake.org/cmake/help/git-stage/module/GoogleTest.html).

Now you can build and run your test:

<pre>
<strong>my_project$ cmake -S . -B build</strong>
-- The C compiler identification is GNU 10.2.1
-- The CXX compiler identification is GNU 10.2.1
...
-- Build files have been written to: .../my_project/build

<strong>my_project$ cmake --build build</strong>
Scanning dependencies of target gtest
...
[100%] Built target gmock_main

<strong>my_project$ cd build && ctest</strong>
Test project .../my_project/build
    Start 1: HelloTest.BasicAssertions
1/1 Test #1: HelloTest.BasicAssertions ........   Passed    0.00 sec

100% tests passed, 0 tests failed out of 1

Total Test time (real) =   0.01 sec
</pre>

Congratulations! You've successfully built and run a test binary using
GoogleTest.

## Next steps

*   [Check out the Primer](primer.md) to start learning how to write simple
    tests.
*   [See the code samples](samples.md) for more examples showing how to use a
    variety of GoogleTest features.