GSW_AI_LAB/yaml-cpp/test/gtest-1.11.0/docs/quickstart-bazel.md

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++11.
• Bazel, the preferred build system used by the GoogleTest team.

See Supported Platforms for more information about platforms compatible with GoogleTest.

If you don't already have Bazel installed, see the Bazel installation guide.

{: .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 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 WORKSPACE 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 WORKSPACE file to specify dependencies. A common and recommended way to depend on GoogleTest is to use a Bazel external dependency via the http_archive rule. To do this, in the root directory of your workspace (my_workspace/), create a file named WORKSPACE with the following contents:

load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")

http_archive(
  name = "com_google_googletest",
  urls = ["https://github.com/google/googletest/archive/609281088cfefc76f9d0ce82e1ff6c30cc3591e5.zip"],
  strip_prefix = "googletest-609281088cfefc76f9d0ce82e1ff6c30cc3591e5",
)

The above configuration declares a dependency on GoogleTest which is downloaded as a ZIP archive 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.

Bazel also needs a dependency on the rules_cc repository to build C++ code, so add the following to the WORKSPACE file:

http_archive(
  name = "rules_cc",
  urls = ["https://github.com/bazelbuild/rules_cc/archive/40548a2974f1aea06215272d9c2b47a14a24e556.zip"],
  strip_prefix = "rules_cc-40548a2974f1aea06215272d9c2b47a14a24e556",
)

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:

#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 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:

load("@rules_cc//cc:defs.bzl", "cc_test")

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

This cc_test rule declares the C++ test binary you want to build, and links to GoogleTest (//:gtest_main) using the prefix you specified in the WORKSPACE file (@com_google_googletest). For more information about Bazel BUILD files, see the Bazel C++ Tutorial.

Now you can build and run your test:

my_workspace$ bazel test --test_output=all //:hello_test
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

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

Next steps

• Check out the Primer to start learning how to write simple tests.
• See the code samples for more examples showing how to use a variety of GoogleTest features.