819485eb80
We were following it about half of the time and we even added it to our former `.mdlrc` file. However, for some reason, MDL doesn't detect this rule when specified in the `.mdlrc` file, so we didn't notice we weren't following it in many cases. Now that we're using a style file to configure MDL, we can enable this rule again and apply it, since now MDL correctly includes it in its report.
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What
Tests that fail randomly are called "flakies", this one seems to be one:
Randomized seed: FILL_WITH_RANDOM_SEED
Failed action: FILL_WITH_A_LINK_WHERE_THE_FAILURE_IS_SHOWN
Failure:
FILL_WITH_FAILURE_REPORT
Tips for flaky hunting
Random values issues
If the problem comes from randomly generated values, running multiple times a single spec could help you reproduce the failure by running at your command line:
for run in {1..10}
do
bin/rspec ./spec/features/budgets/investments_spec.rb:256
done
You can also try running a single spec:
Add option :focus to the spec and push your branch to Github, for example:
scenario 'Show', :focus do
But remember to remove that :focus changes afterwards when submitting your PR changes!
Test order issues
Running specs in the order they failed may discover that the problem is that a previous test sets an state in the test environment that makes our flaky fail/pass. Tests should be independent from the rest.
After executing rspec you can see the seed used, add it as an option to rspec, for example:
bin/rspec --seed 55638 (check Randomized seed value at beginning of issue)
Other things to watch for
- Time related issues (current time, two time or date comparisons with miliseconds/time when its not needed)
- You can check the Semaphore tutorial about flaky tests
Final thoughts
The true objective of this issue is not "to fix" a flaky spec, but to change a spec that randomly fails into one that we can trust when it passes (or fails).
That means you've to think "What are we testing here?" and "Can we test the same thing in another way?" or "Are we already testing this somewhere else at least partially?".
Sometimes the fix is to re-write the entire tests with a different approach, or to extend an existing spec. Tests are sometimes written without taking a look at other tests files neither near scenarios.