C++ project with Bazel and GTest - c++

Question

I want to create a Bazel C++ project with gtest for unit tests.
What is the minimal setup?
(I only have Bazel installed on my computer and I am running under Linux)

Answer 1

This is even easier now that googletest provides a BUILD file:
In WORKSPACE
load("#bazel_tools//tools/build_defs/repo:git.bzl", "git_repository")
git_repository(
name = "gtest",
remote = "https://github.com/google/googletest",
branch = "v1.10.x",
)
In BUILD
cc_test (
name = "hello_test",
srcs = [
"hello_test.cc",
],
deps = [
"#gtest//:gtest",
"#gtest//:gtest_main" # Only if hello_test.cc has no main()
],
)

Answer 2

The project structure is:
.
├── bin
│   ├── BUILD
│ ├── hello.cpp
├── MyLib
│   ├── BUILD
│ ├── message.hpp
│ ├── message.cpp
│ ├── ...
├── test
│ ├── BUILD
│ ├── message_test.cpp
│ ├── ...
├── gmock.BUILD
└── WORKSPACE
Files related to Bazel+GTest
WORKSPACE
There you download gtest from github:
new_git_repository(
name = "googletest",
build_file = "gmock.BUILD",
remote = "https://github.com/google/googletest",
tag = "release-1.8.0",
)
You define a gmock BUILD file defined below:
gmock.BUILD
This BUILD file is in charge of compiling gtest/gmock:
cc_library(
name = "gtest",
srcs = [
"googletest/src/gtest-all.cc",
"googlemock/src/gmock-all.cc",
],
hdrs = glob([
"**/*.h",
"googletest/src/*.cc",
"googlemock/src/*.cc",
]),
includes = [
"googlemock",
"googletest",
"googletest/include",
"googlemock/include",
],
linkopts = ["-pthread"],
visibility = ["//visibility:public"],
)
cc_library(
name = "gtest_main",
srcs = ["googlemock/src/gmock_main.cc"],
linkopts = ["-pthread"],
visibility = ["//visibility:public"],
deps = [":gtest"],
)
test/BUILD
This build file generate the tests:
cc_test(
name = "MyTest",
srcs = glob(["**/*.cpp"]),
deps = ["//MyLib:MyLib",
"#googletest//:gtest_main"],
)
The test/message_test.cpp file is defined by:
#include "gtest/gtest.h"
#include "MyLib/message.hpp"
TEST(message_test,content)
{
EXPECT_EQ(get_message(),"Hello World!");
}
And that is all! The other files are defined as usual:
Files for the supporting example
MyLib/BUILD
Creates the libMyLib.so and libMyLib.a libraries.
cc_library(
name="MyLib",
hdrs=glob(["**/*.hpp"]),
srcs=glob(["**/*.cpp"]),
visibility = ["//visibility:public"],
)
with a basic message.hpp
#include <string>
std::string get_message();
and message.cpp
#include "MyLib/message.hpp"
std::string get_message()
{
return "Hello World!";
}
example.
bin/BUILD
Creates the hello executable.
cc_binary(
name = "hello",
srcs = ["hello.cpp"],
deps = ["//MyLib:MyLib"],
)
which is:
#include "MyLib/message.hpp"
#include <iostream>
int main()
{
std::cout << "\n" << get_message() << std::endl;
return EXIT_SUCCESS;
}
Usage:
Compiles all targets:
This will also download gtest from its github repo and compile it
bazel build ...
Checks the hello target:
You can run it with:
bazel run bin:hello
Running your tests using GTest
That was the main point of this note:
bazel test ... --test_output=errors
You should get something like:
INFO: Analysed 3 targets (0 packages loaded).
INFO: Found 2 targets and 1 test target...
INFO: Elapsed time: 0.205s, Critical Path: 0.05s
INFO: Build completed successfully, 2 total actions
//test:MyTest
PASSED in 0.0s
Executed 1 out of 1 test: 1 test passes.
Reproduce the results
For your ease I have created a github repo containing this example. I hope it works out of the box.

Answer 3

The current recommended practice is to use http_archive to avoid depending on the system git and take advantage of repository cache.
In WORKSPACE
# 5376968f6948923e2411081fd9372e71a59d8e77 is the commit sha for v1.12.0.
# Periodically update to the latest to "live at head"
http_archive(
name = "com_google_googletest",
sha256 = "199e68f9dff997b30d420bf23cd9a0d3f66bfee4460e2cd95084a2c45ee00f1a",
strip_prefix = "googletest-5376968f6948923e2411081fd9372e71a59d8e77",
urls = ["https://github.com/google/googletest/archive/5376968f6948923e2411081fd9372e71a59d8e77.zip"],
)
In test/BUILD
cc_test(
name = "test_greet",
srcs = ["greeting_test.cpp"],
deps = [
"//src:greeting",
"#com_google_googletest//:gtest_main",
],
)