# Quickstart: Building with Bazel

This tutorial aims to get you up and running with GoogleTest using the Bazel
build system. If you're using GoogleTest for the first time or need a refresher,
we recommend this tutorial as a starting point.

## 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++17.
*   [Bazel](https://bazel.build/) 7.0 or higher, the preferred build system used
    by the GoogleTest team.

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

If you don't already have Bazel installed, see the
[Bazel installation guide](https://bazel.build/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 Bazel workspace

A
[Bazel workspace](https://docs.bazel.build/versions/main/build-ref.html#workspace)
is a directory on your filesystem that you use to manage source files for the
software you want to build. Each workspace directory has a text file named
`MODULE.bazel` which may be empty, or may contain references to external
dependencies required to build the outputs.

First, create a directory for your workspace:

```
$ mkdir my_workspace && cd my_workspace
```

Next, you’ll create the `MODULE.bazel` file to specify dependencies. As of Bazel
7.0, the recommended way to consume GoogleTest is through the
[Bazel Central Registry](https://registry.bazel.build/modules/googletest). To do
this, create a `MODULE.bazel` file in the root directory of your Bazel workspace
with the following content:

```
# MODULE.bazel

# Choose the most recent version available at
# https://registry.bazel.build/modules/googletest
bazel_dep(name = "googletest", version = "1.18.0")
```

Now you're ready to build C++ code that uses GoogleTest.

## Create and run a binary

With your Bazel workspace set up, you can now use GoogleTest code within your
own project.

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

```
cc_test(
    name = "hello_test",
    size = "small",
    srcs = ["hello_test.cc"],
    deps = [
        "@googletest//:gtest",
        "@googletest//:gtest_main",
    ],
)
```

This `cc_test` rule declares the C++ test binary you want to build, and links to
the GoogleTest library (`@googletest//:gtest"`) and the GoogleTest `main()`
function (`@googletest//:gtest_main`). For more information about Bazel `BUILD`
files, see the
[Bazel C++ Tutorial](https://docs.bazel.build/versions/main/tutorial/cpp.html).

{: .callout .note}
NOTE: In the example below, we assume Clang or GCC and set `--cxxopt=-std=c++17`
to ensure that GoogleTest is compiled as C++17 instead of the compiler's default
setting. For MSVC, the equivalent would be `--cxxopt=/std:c++17`. See
[Supported Platforms](platforms.md) for more details on supported language
versions.

Now you can build and run your test:

<pre>
<strong>$ bazel test --cxxopt=-std=c++17 --test_output=all //:hello_test</strong>
INFO: Analyzed target //:hello_test (26 packages loaded, 362 targets configured).
INFO: Found 1 test target...
INFO: From Testing //:hello_test:
==================== Test output for //:hello_test:
Running main() from gmock_main.cc
[==========] Running 1 test from 1 test suite.
[----------] Global test environment set-up.
[----------] 1 test from HelloTest
[ RUN      ] HelloTest.BasicAssertions
[       OK ] HelloTest.BasicAssertions (0 ms)
[----------] 1 test from HelloTest (0 ms total)

[----------] Global test environment tear-down
[==========] 1 test from 1 test suite ran. (0 ms total)
[  PASSED  ] 1 test.
================================================================================
Target //:hello_test up-to-date:
  bazel-bin/hello_test
INFO: Elapsed time: 4.190s, Critical Path: 3.05s
INFO: 27 processes: 8 internal, 19 linux-sandbox.
INFO: Build completed successfully, 27 total actions
//:hello_test                                                     PASSED in 0.1s

INFO: Build completed successfully, 27 total actions
</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.
