Allow suppressing error boundary logs from intentionally thrown/caught errors

[gaearon]

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(This is a repost of jestjs/jest#4597 by @erikras.)

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

Somewhere in between?

What is the current behavior?

When I'm running tests on my library, there are some behaviors that I want to test do throw an error. These currently result in:

Consider adding an error boundary to your tree to customize error handling behavior.
You can learn more about error boundaries at https://fb.me/react-error-boundaries.

...being output to the console. This error is great in an application, but not so great for a library test.

What is the expected behavior?

It would be great if I could do something like:

expect(() => {
  TestUtils.renderIntoDocument(<DoSomething naughty/>)
})
.toThrow(/Bad developer!/)
.andCatch() // <---- prevents React 16 error boundary warning

Please provide your exact Jest configuration and mention your Jest, node, yarn/npm version and operating system.

jest@21.2.1
react@16.0.0
react-dom@16.0.0

See also

• Difficult to track down the source of a boolean prop warning #11083
• The fake event trick for rethrowing errors in DEV fires unexpected global error handlers and makes testing harder #10474 (comment)

[gaearon]

cc @acdlite @sebmarkbage @bvaughn

[bvaughn]

This error is great in an application, but not so great for a library test.

One way to prevent these unwanted messages from appearing in tests is:

spyOn(console, 'error'); // In tests that you expect errors

If this is too onerous you could also do it globally in a Jest setup file.

I don't think we saw these warnings. But we probably mocked something in Jest at some point and that's why.

Regarding @gaearon's comment on the original issue, I believe we don't see them because we do a mix of spying on console.error and mocking ReactFiberErrorLogger.

Unfortunately mocking out ReactFiberErrorLogger isn't really recommended outside of the context of the React project. We should come up with a cleaner story for this in order to simplify external testing.

[travi]

i've been running into similar issues in mocha where error behavior under test is being hidden by this warning.

my issue was made somewhat worse because of the fact that i override console.error and console.warn in my tests to ensure that react warnings cause test failures. this caused those errors to be caught by this error boundary log even earlier in some cases. removing these overrides allowed me to see further error output, but resolving the newly revealed output brought me back to the boundary logs again.

if there is anything i could help with as far as insight from testing with mocha related to this issue, i'm happy to.

[gaearon]

i've been running into similar issues in mocha where error behavior under test is being hidden by this warning.

Can you clarify what you mean by this?

When you see this warning but your test doesn't fail, it means your code is throwing somewhere but then this error gets caught and never reaches your test's stack frame. Unless you're intentionally testing error cases, this indicates a bug in your code. But this warning itself doesn't "hide" the original error. If we removed the warning your bug would be completely invisible (since something catches it). The warning surfaces it.