eRCaGuy_gtest_practice

googletest (gtest) & googlemock (gmock) practice

Author

Gabriel Staples
www.ElectricRCAircraftGuy.com

Status

It works! I am able to successfully write and run google tests and mocks. Follow Build & Run instructions below.

First, follow the instructions in the eRCaGuy_hello_world/cpp/README.md here: C++ Googletest setup: how to build googletest (gtest and gmock) with the gcc/g++ compiler.
Then, run any of the eRCaGuy_hello_world/cpp/gtest_demo__* files by running the build-and-run commands in the comments at the top of each of those files.

You can also run any eRCaGuy_hello_world/cpp/*_unittest.cpp files, as these are also gtest files. See their build-and-run instructions in the comments at the top of each file.

Example build-and-run command for the eRCaGuy_hello_world/cpp/swap_bytes_lib_unittest.cpp file:

time ( \
    time g++ -Wall -Wextra -Werror -O3 -std=c++17 -pthread \
    -I"googletest/googletest/include" -I"googletest/googlemock/include" \
    swap_bytes_lib_unittest.cpp \
    swap_bytes_lib.cpp \
    bin/libgtest.a bin/libgtest_main.a \
    -o bin/a \
    && time bin/a \
)

You can find all unittest files like this:

# cd into this dir
cd path/to/eRCaGuy_hello_world/cpp
# list all files with the word `unittest` in them, in a single-column (`-1`)
# list format
ls -1 *unittest*

Sample run and output to find all unittest files:

eRCaGuy_hello_world/cpp$ ls -1 *unittest*
curl_lib_unittest.cpp
curl_systemcall_lib_unittest.cpp
gtest_demo__sample1_factorial_and_is_prime_unittest.cc
swap_bytes_lib_unittest.cpp
systemcall_lib_unittest.cpp

Cross-references

Inspired by this question, "google mock - can I call EXPECT_CALL multiple times on same mock object?", and my big Stack Overflow answer to it here
and my big discussion with @luantkow under his answer here, as well as on his code gist (under GitHub username @lukant) here.

To Build (Ubuntu instructions):

Install Bazel: https://docs.bazel.build/versions/master/install-ubuntu.html
Download the latest Googletest release from here (I used v1.10.0). Extract it. Now you have a "googletest-release-1.10.0" directory. Symbolically link it into this project as follows:
```
cd eRCaGuy_gtest_practice/googletest
ln -si /path/to/folder/googletest-release-1.10.0 .
```

Ensure you are in the "eRCaGuy_gtest_practice" dir, and run the bazel build command:

time bazel build //...  # Build ALL build targets

Here's a sample of successful output:

$ time bazel build //...
INFO: Analyzed target //:gmock_tests (0 packages loaded, 0 targets configured).
INFO: Found 1 target...
Target //:gmock_tests up-to-date:
  bazel-bin/gmock_tests
INFO: Elapsed time: 0.316s, Critical Path: 0.01s
INFO: 0 processes.
INFO: Build completed successfully, 1 total action

real    0m0.408s
user    0m0.024s
sys 0m0.024s

To run the tests

In short:

time bazel test --test_output=errors --test_arg=--gtest_color=yes //...             # run ALL tests
time bazel test --test_output=errors --test_arg=--gtest_color=yes //:gmock_test1    # run only test 1
time bazel test --test_output=errors --test_arg=--gtest_color=yes //:gmock_test2    # run only test 2

Details:

time bazel test //...           # run ALL tests
time bazel test //:gmock_tests  # run tests for just this "gmock_tests" target

To log all errors (failed test results) to stdout, add --test_output errors. See: https://groups.google.com/forum/#!topic/bazel-discuss/2mJPklIaCeo and see bazel help test for additional options. Ex:

time bazel test --test_output errors //...  # log all errors (failed test results) to stdout

To log all output (failed AND passed results) to stdout, add --test_output all. Ex:

time bazel test --test_output all //...     # log ALL output (both failed & passed test results) to stdout

But, this is drab! I want to see the failures in red when they occur! To do that, we need to add the --gtest_color=yes option to the test binary when it is called. Do that with the bazel --test_arg option: --test_arg=--gtest_color=yes. The final command will now look like this:

time bazel test --test_output=errors --test_arg=--gtest_color=yes //...

Note that you can also manually pass these flags to a binary you have successfully built, such as bazel-bin/gmock_tests, as follows:

bazel-bin/gmock_tests --gtest_color=yes

References:

Use the bazel --test_arg option to pass arguments to tests! https://stackoverflow.com/questions/50877601/how-to-pass-custom-flags-to-bazel-test-command/50890446#50890446
Pass --gtest_color=yes to any test binary to see colored output: https://github.com/google/googletest/blob/master/googletest/docs/advanced.md#controlling-test-output
If bazel isn't outputting color for some reason add this after the bazel build or bazel test command as well: --color=yes; see: https://docs.bazel.build/versions/master/user-manual.html#flag--color
Add color to text in markdown (ie: here is how I added red to this readme itself): https://stackoverflow.com/questions/35465557/how-to-apply-color-in-markdown/43355451#43355451

Other bazel commands:

bazel query //... # query for a list of all possible build targets

Adding your own test:

Just create your own .cpp test file or a .h/.cpp test file pair with some tests in it. Then, modify the BUILD.bazel file, either adding your new .h and .cpp files to the srcs list in an existing cc_test, or creating a new cc_test specifically for your new test files.

ElectricRCAircraftGuy/eRCaGuy_gtest_practice