Ideally, tests should be run every time we intend to share our code with anyone - be it our team or the whole world. It is a tech lead’s wet dream to work in an environment where every dev thoroughly tests their solutions. As this might be impossible, we can have the next best thing.
We can make tests run automatically every time new or modified code is introduced into the codebase.
Let’s assume we do everything in Docker and any new code is built by a server that prevents merging changes until a new image is successfully created.
# When we run the script: bash test_scenario.sh # We get: Test #1: PASS Test #2: PASS Test #3: PASS Test #4: PASS Test #5: PASS Test #6: PASS Test #7: PASS
Now, we can create a
Dockerfile that will use the above script to check if our app is behaving properly.
FROM bash COPY test*.sh ./ RUN bash test_scenario.sh
The docker image described above will not be built if the tests fail. Like this:
# Try to build the image docker build . # We get: Sending build context to Docker daemon 4.608kB Step 1/3 : FROM bash ---> 78664daf24f4 Step 2/3 : COPY test*.sh ./ ---> fe75cddc7f0f Step 3/3 : RUN bash test_scenario.sh ---> Running in 010702b02aea Test #1: PASS Test #2: PASS Test #3: PASS Test #4: PASS Test #5: PASS Test #6: PASS Test #7: FAIL The command '/bin/sh -c bash test_scenario.sh' returned a non-zero code: 1
With this approach, there will never exist a runnable version of our app that did not pass all the required tests. When we fix the app, the test will work again.
# [...] Step 3/3 : RUN bash test_scenario.sh ---> Running in c2d555481c28 Test #1: PASS Test #2: PASS Test #3: PASS Test #4: PASS Test #5: PASS Test #6: PASS Test #7: PASS Removing intermediate container c2d555481c28 ---> d41d9ecb5ed9 Successfully built d41d9ecb5ed9
… and we will have a new image built and ready to use.
Of course, there are different types of tests. Some of them will not be able to run before the application is actually built and deployed to a testing environment. Real-life requires more sophisticated configurations, but the general idea is here.
*.shfiles and the
Dockerfileare available on GitHub Gist .