NestedInput.nested_event_filter_receives_keyboard_from_host CI failure

happened on a vivid ppa builder recently:

[----------] 5 tests from NestedInput
[ RUN ] NestedInput.nested_event_filter_receives_keyboard_from_host
[2016-09-13 09:45:37.394318] mirserver: Starting
[2016-09-13 09:45:37.394450] mirserver: Selected driver: mir:stub-graphics (version 0.25.0)
[2016-09-13 09:45:37.395335] mirserver: Using software cursor
[2016-09-13 09:45:37.396233] mirserver: Initial display configuration:
[2016-09-13 09:45:37.396609] mirserver: 1.1: VGA 0.0" 0x0mm
[2016-09-13 09:45:37.396621] mirserver: Current mode 640x480 60.00Hz
[2016-09-13 09:45:37.396630] mirserver: Preferred mode 640x480 60.00Hz
[2016-09-13 09:45:37.396637] mirserver: Logical position +0+0
[2016-09-13 09:45:37.396951] mirserver: 1.2: VGA 0.0" 0x0mm
[2016-09-13 09:45:37.396961] mirserver: Current mode 1920x1080 60.00Hz
[2016-09-13 09:45:37.396969] mirserver: Preferred mode 1920x1080 60.00Hz
[2016-09-13 09:45:37.396976] mirserver: Logical position +480+0
[2016-09-13 09:45:37.398601] mirserver: Selected input driver: mir:stub-input (version: 0.25.0)
[2016-09-13 09:45:37.398627] mirserver: Mir version 0.25.0
[2016-09-13 09:45:37.407508] mirserver: Starting
[2016-09-13 09:45:37.410493] mirserver: Using nested cursor
[2016-09-13 09:45:37.412750] mirserver: Initial display configuration:
[2016-09-13 09:45:37.413176] mirserver: 1.1: VGA 0.0" 0x0mm
[2016-09-13 09:45:37.413191] mirserver: Current mode 640x480 60.00Hz
[2016-09-13 09:45:37.413200] mirserver: Preferred mode 640x480 60.00Hz
[2016-09-13 09:45:37.413207] mirserver: Logical position +0+0
[2016-09-13 09:45:37.413550] mirserver: 1.2: VGA 0.0" 0x0mm
[2016-09-13 09:45:37.413560] mirserver: Current mode 1920x1080 60.00Hz
[2016-09-13 09:45:37.413568] mirserver: Preferred mode 1920x1080 60.00Hz
[2016-09-13 09:45:37.413575] mirserver: Logical position +0+0
[2016-09-13 09:45:37.414800] mirserver: Mir version 0.25.0
[2016-09-13 09:45:37.424599] mirserver: New display configuration:
unknown file: Failure

Unexpected mock function call - returning default value.
Function call: handle(key_event(when=2291054130298 (0.340632ms ago), from=1, down, code=97, scan=30, modifiers=1))
Returns: false
Google Mock tried the following 3 expectations, but none matched:

/«BUILDDIR»/mir-0.25.0+15.04.20160913.1/tests/acceptance-tests/test_nested_input.cpp:195: tried expectation #0: EXPECT_CALL(nested_event_filter, handle(mt::InputDeviceStateEvent()))...
Expected arg #0: input device state event
Actual: key_event(when=2291054130298 (0.250075ms ago), from=1, down, code=97, scan=30, modifiers=1)
Expected: to be called once
Actual: never called - unsatisfied and active
/«BUILDDIR»/mir-0.25.0+15.04.20160913.1/tests/acceptance-tests/test_nested_input.cpp:196: tried expectation #1: EXPECT_CALL(nested_event_filter, handle(mt::KeyOfScanCode(30)))...
Expected: all pre-requisites are satisfied
Actual: the following immediate pre-requisites are not satisfied:
/«BUILDDIR»/mir-0.25.0+15.04.20160913.1/tests/acceptance-tests/test_nested_input.cpp:195: pre-requisite #0
(end of pre-requisites)
Expected: to be called at least once
Actual: never called - unsatisfied and active
/«BUILDDIR»/mir-0.25.0+15.04.20160913.1/tests/acceptance-tests/test_nested_input.cpp:200: tried expectation #2: EXPECT_CALL(nested_event_filter, handle(mt::KeyOfScanCode(54)))...
Expected arg #0: key of scan code 54
Actual: key_event(when=2291054130298 (0.331302ms ago), from=1, down, code=97, scan=30, modifiers=1)
Expected: to be called twice
Actual: never called - unsatisfied and active
[2016-09-13 09:45:37.425103] mirserver: 1.1: VGA 0.0" 0x0mm
[2016-09-13 09:45:37.425112] mirserver: Current mode 640x480 60.00Hz
[2016-09-13 09:45:37.425122] mirserver: Preferred mode 640x480 60.00Hz
[2016-09-13 09:45:37.425129] mirserver: Logical position +0+0
[2016-09-13 09:45:37.425510] mirserver: 1.2: VGA 0.0" 0x0mm
[2016-09-13 09:45:37.425521] mirserver: Current mode 1920x1080 60.00Hz
[2016-09-13 09:45:37.425529] mirserver: Preferred mode 1920x1080 60.00Hz
[2016-09-13 09:45:37.425536] mirserver: Logical position +0+0
[2016-09-13 09:45:37.435728] mirserver: Stopping
[2016-09-13 09:45:37.437060] mirserver: New display configuration:
[2016-09-13 09:45:37.437673] mirserver: 1.1: VGA 0.0" 0x0mm
[2016-09-13 09:45:37.437691] mirserver: Current mode 640x480 60.00Hz
[2016-09-13 09:45:37.437702] mirserver: Preferred mode 640x480 60.00Hz
[2016-09-13 09:45:37.437712] mirserver: Logical position +0+0
[2016-09-13 09:45:37.438162] mirserver: 1.2: VGA 0.0" 0x0mm
[2016-09-13 09:45:37.438177] mirserver: Current mode 1920x1080 60.00Hz
[2016-09-13 09:45:37.438188] mirserver: Preferred mode 1920x1080 60.00Hz
[2016-09-13 09:45:37.438198] mirserver: Logical position +480+0
[2016-09-13 09:45:37.438325] mirserver: Stopping
[ FAILED ] NestedInput.nested_event_filter_receives_keyboard_from_host (48 ms)