Seen in https://gerrit.wikimedia.org/r/c/mediawiki/extensions/GrowthExperiments/+/720937 multiple times (e.g. https://integration.wikimedia.org/ci/job/wmf-quibble-selenium-php72-docker/112888/console ):
```
21:53:17 > @ selenium-test /workspace/src/extensions/MobileFrontend
21:53:17 > wdio tests/selenium/wdio.conf.js
21:53:17
21:53:17
21:53:18 Execution of 2 spec files started at 2021-09-16T04:53:18.122Z
...
21:53:26 [0-1]
21:54:08 <--- Last few GCs --->
21:54:08
21:54:08 [8601:0xf6c670] 47768 ms: Mark-sweep 1356.4 (1415.7) -> 1356.4 (1384.7) MB, 705.8 / 0.0 ms (average mu = 0.231, current mu = 0.000) last resort GC in old space requested
21:54:08 [8601:0xf6c670] 48492 ms: Mark-sweep 1356.4 (1384.7) -> 1356.4 (1384.7) MB, 724.1 / 0.0 ms (average mu = 0.125, current mu = 0.000) last resort GC in old space requested
21:54:08
21:54:08 [0-1]
21:54:08 <--- JS stacktrace --->
21:54:08
21:54:08 ==== JS stack trace =========================================
21:54:08
21:54:08 0: ExitFrame [pc: 0x11bf7c8d452b]
21:54:08 Security context: 0x1a1e88a2ede9 <JSObject>
21:54:08 1: promiseRejectHandler(aka promiseRejectHandler) [0x26d8d4d02761] [internal/process/promises.js:~27] [pc=0x11bf7ca06b95](this=0x292f111825d9 <undefined>,type=0,promise=0x37cf557d4401 <Promise map = 0x1ad284c09319>,reason=0x37cf557d42c1 <Error map = 0x1ad284c760e1>)
21:54:08 2: InternalFrame [pc: 0x11bf7c81bd8f]
21:54:08 3: EntryFrame [pc: 0x11bf7c8e3ea1]
21:54:08 4: E...
21:54:08
21:54:08 [0-1] FATAL ERROR: CALL_AND_RETRY_LAST Allocation failed - JavaScript heap out of memory
21:54:08 [0-1] 1: 0x7f231549b2d8 node::Abort() [/lib/x86_64-linux-gnu/libnode.so.64]
21:54:08 [0-1] 2: 0x7f231549b321 [/lib/x86_64-linux-gnu/libnode.so.64]
21:54:08 [0-1] 3: 0x7f231567c5c2 v8::Utils::ReportOOMFailure(v8::internal::Isolate*, char const*, bool) [/lib/x86_64-linux-gnu/libnode.so.64]
21:54:08 [0-1] 4: 0x7f231567c818 v8::internal::V8::FatalProcessOutOfMemory(v8::internal::Isolate*, char const*, bool) [/lib/x86_64-linux-gnu/libnode.so.64]
21:54:08 [0-1] 5: 0x7f2315a0b542 [/lib/x86_64-linux-gnu/libnode.so.64]
21:54:08 [0-1] 6: 0x7f2315a1f0e7 v8::internal::Heap::AllocateRawWithRetryOrFail(int, v8::internal::AllocationSpace, v8::internal::AllocationAlignment) [/lib/x86_64-linux-gnu/libnode.so.64]
21:54:08 [0-1] 7: 0x7f23159ed7b7 v8::internal::Factory::AllocateRawArray(int, v8::internal::PretenureFlag) [/lib/x86_64-linux-gnu/libnode.so.64]
21:54:08 [0-1] 8: 0x7f23159edc34 v8::internal::Factory::NewFixedArrayWithFiller(v8::internal::Heap::RootListIndex, int, v8::internal::Object*, v8::internal::PretenureFlag) [/lib/x86_64-linux-gnu/libnode.so.64]
21:54:08 [0-1] 9: 0x7f23159b533d [/lib/x86_64-linux-gnu/libnode.so.64]
21:54:08 [0-1] 10: 0x7f2315c1293c v8::internal::Runtime_GrowArrayElements(int, v8::internal::Object**, v8::internal::Isolate*) [/lib/x86_64-linux-gnu/libnode.so.64]
21:54:08 [0-1] 11: 0x11bf7c8d452b
21:54:08 [0-1] FAILED in chrome - /tests/selenium/specs/user_page.js
```
MobileFrontend is one of the rare repositories that's still on WebdriverIO v6. Most of the repositores are on v7. See T274579. I'll try to finish the update to see if it fixes see problem. See T289184.
It's also one of the rare repositories that uses Cucumber testing framework, instead of the default Mocha. I'm not sure if that's causing any trouble.
It's also one of the rare repositories that has all of it's tests skipped.