XCode 13.1: Undefined symbol: __swift_FORCE_LOAD_$_XCTestSwiftSupport - ios

Question

My app was running perfectly without any errors or warnings yesterday. But when I tried to run it today, the build failed - I haven't changed anything in the code:
Undefined symbol: __swift_FORCE_LOAD_$_XCTestSwiftSupport
How to fix this, and why would something like this occur suddenly when it was working before?
And this is an issue I've been experiencing with XCode a lot lately. My code will be running smoothly without any errors, but then XCode will randomly start throwing errors when I relaunch it at a different time - without making any changes in the actual code.
I have included some photos and the full text of those photos:
InventoryApp 3 issues
Warning
Could not find or use auto-linked library 'XCTestSwiftSupport'
Could not find or use auto linked framework 'XCTest'
Error
Undefined symbol: __swift FORCE LOAD $ XCTestSwiftSupport
ld: warning: Could not find or use auto-linked library 'XCTestSwiftSupport'
ld: warning: Could not find or use auto-linked framework
'XCTest'
Undefined symbols for architecture arm64:
"__swift_FORCE_LOAD_$_XCTestSwiftSupport", referenced from:
__swift_FORCE_LOAD_$_XCTestSwiftSupport_$_inventoryApp in Button.o
__swift_FORCE_LOAD_$_XCTestSwiftSupport_$_inventoryApp in ViewModel.o
__swift_FORCE_LOAD_$_XCTestSwiftSupport_$_inventoryApp in Inventory.o
__swift_FORCE_LOAD_$_XCTestSwiftSupport_$_inventoryApp in AddView.o
__swift_FORCE_LOAD_$_XCTestSwiftSupport_$_inventoryApp in ScannerView.o
__swift_FORCE_LOAD_$_XCTestSwiftSupport_$_inventoryApp in RegisterView.o
__swift_FORCE_LOAD_$_XCTestSwiftSupport_$_inventoryApp in ContentView.o
...
(maybe you meant: __swift_FORCE_LOAD_$_XCTestSwiftSupport_$_inventoryApp)
ld: symbol(s) not found for architecture arm64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

Answer 1

This condition also occurs if you add
import XCTest
to a file in a non-test bundle.

Answer 2

I solved this error by navigation to target app settings > Build Phases > Link Binary With Libraries > add the linked library "XCTest.framework".
If afterwards your app starts crashing, aborting with the following errors:
dyld: Library not loaded: #rpath/XCTest.framework/Versions/A/XCTest
0_abort_with_payload
Then you can take a look at the suggestions on this thread: Xcode 5.0.2 dyld: Library not loaded: #rpath/XCTest.framework/Versions/A/XCTest
The solution that worked for me was:
Navigate to target app > Build Settings > Linking > Other Linker Flags > editing or adding -weak_framework "XCTest"

Answer 3

This error randomly started to occur on my Xcode project today. I changed the setting.
PROJECT -> Build Settings -> Build Options -> Enable Testing Search Paths
from No to Yes, and the build succeeded.
Edit:...
This setting is on by default if the project is created with a testing target included. In my case I believe I added the testing target later so this setting will have been false. Although, I can't say why it didn't break as soon as I added the testing target.
See:
https://xcodebuildsettings.com

Answer 4

None of the above worked for me. In my case, a couple of mock files were targeted to both the framework and unit testing bundle. I just unticked the framework one to get rid of this error on the inspector.

Answer 5

I solved this error by navigation to target app settings > Build Phases > Link Binary with Libraries > add the linked library "XCTest.framework".
The action above is totally the same as the solutions above, though the issue "Library not loaded" appeared raised.
I solved the "Library not loaded" issue by setting up the framework to be optional while linked library.
[enter image description here][1]
It works for me in Xcode 13.2.1.