Single file testing doesn't work correctly after migration to Jest 22

[aakula-edmunds]

Do you want to request a feature or report a bug?
a bug

What is the current behavior?
Jest tries running test 2 times instead of 1

• 1st run is successful
• 2nd run fails with unmatched snapshot error if such test scenario exists

If the current behavior is a bug, please provide the steps to reproduce and
either a repl.it demo through https://repl.it/languages/jest or a minimal
repository on GitHub that we can yarn install and yarn test.
https://github.com/aakula-edmunds/sampleJestIssue

What is the expected behavior?
A test should be run only once.

Please provide your exact Jest configuration and mention your Jest, node,
yarn/npm version and operating system.
https://github.com/aakula-edmunds/sampleJestIssue/tree/master/archetype/config/jest

[rickhanlonii]

Hey @aakula-edmunds, it looks like the issue on your branch happens on Jest 21 as well and is related to how you have the enzyme serializer configured (not a bug)

If you have any more questions, I'm happy to help more on stackoverflow or our discord channel

[dan-codes-16]

@rickhanlonii thanks a lot for your answer, but how is a double test related to enzyme configuration? If enzyme is removed at all jest still tries to execute the same test twice. Maybe it wasn't clear in the original message from @aakula-edmunds, but when you try to call $ yarn test /path/to/test-file.test.js jest tries to test this file twice like it is 2 separate test files. For me it looks like 1st test is done with /client project configuration and second with /server project configuration. And this behavior wasn't so in Jest 21.

[rickhanlonii]

Ah, I see! I can confirm this (introduced in 22.0.0)

When you run yarn test server/sample.test.jsx it runs both the client and server project configs for that single test file, even though the client config shouldn't run based on the testMatch

Thanks for following up @adaniliuk!

[rickhanlonii]

Looks like this was introduced here

With that change, we will run the tests on the files passed in and ignore the matchers

[rickhanlonii]

@aakula-edmunds @adaniliuk thanks for the report, this will be fixed in the next release

[dan-codes-16]

@rickhanlonii great, thanks a lot for a quick turn around!

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