Occasionaly test failure with message expected to eventually be falsy, got <0>

[manuyavuz-pointr]

• I have read CONTRIBUTING and have done my best to follow them.

What did you do?

I have a UI test case with following expectation:

expect(self.app.keyboards.firstMatch.exists).withTimeout(5).toEventually(beFalsy());

This code occasionally fails on CI builds (when run with address sanitizer enabled) with the following failure message:

expected to eventually be falsy, got <0>

What did you expect to happen?

This error should never happen in my opinion as the expression in expect() returns a BOOL, and matcher is beFalsy(), which should both match with false boolean values and nil values as it's implicitly falsy.

What actually happened instead?

This code occasionally fails on CI builds (when run with address sanitizer enabled) with the following failure message:

expected to eventually be falsy, got <0>

Environment

List the software versions you're using:

• Nimble: 9.0.0
• Xcode Version: 12.0 (Open Xcode; In menubar: Xcode > About Xcode)
• Swift Version: Xcode Default (Open Xcode Preferences; Components > Toolchains. If none, use Xcode Default.)

Please also mention which package manager you used and its version. Delete the
other package managers in this list:

• Cocoapods: 1.10.0 (Use pod --version in Terminal)

Project that demonstrates the issue

I don't have a project as I could not reproduce the issue locally yet.

Any guess how this could happen?

Thanks!

[ikesyo]

Duplicate of #360.