Merge lp:~vanvugt/mir/catchup-1570698 into lp:mir

[Daniel van Vugt]

Improve the robustness of acceptance test:
  TestClientInput.receives_one_touch_event_per_frame
so that it is now less likely to fail on a heavily loaded or slow system.
(LP: #1570698)

In reality we haven't seen this test actually fail for almost three months but this is aimed at helping Brandon to get one of his branches to pass.

I actually started out trying to introduce fake server timestamps but found they created a lot of failures under Valgrind, presumably because the client wasn't using the same fake clock. But we should try to do that in future.

[Chris Halse Rogers (raof)]

I think you could probably introduce a fake clock via a LD_PRELOAD library; https://github.com/wolfcw/libfaketime would be one such (which I don't think does *exactly* what we want, but could be cribbed from/patched to make something useful to us).

This seems to be a strict improvement on the status quo, though.

review: Approve

[Mir CI Bot (mir-ci-bot)]

PASSED: Continuous integration, rev:3713
https://mir-jenkins.ubuntu.com/job/mir-ci/1798/
Executed test runs:
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-mir/2248
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-0-fetch/2311
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-1-sourcepkg/release=vivid+overlay/2302
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-1-sourcepkg/release=xenial+overlay/2302
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-1-sourcepkg/release=yakkety/2302
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=clang,platform=mesa,release=yakkety/2276
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=clang,platform=mesa,release=yakkety/2276/artifact/output/*zip*/output.zip
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=gcc,platform=mesa,release=xenial+overlay/2276
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=gcc,platform=mesa,release=xenial+overlay/2276/artifact/output/*zip*/output.zip
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=gcc,platform=mesa,release=yakkety/2276
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=amd64,compiler=gcc,platform=mesa,release=yakkety/2276/artifact/output/*zip*/output.zip
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=i386,compiler=gcc,platform=android,release=vivid+overlay/2276
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=i386,compiler=gcc,platform=android,release=vivid+overlay/2276/artifact/output/*zip*/output.zip
    SUCCESS: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=i386,compiler=gcc,platform=mesa,release=xenial+overlay/2276
        deb: https://mir-jenkins.ubuntu.com/job/build-2-binpkg-mir/arch=i386,compiler=gcc,platform=mesa,release=xenial+overlay/2276/artifact/output/*zip*/output.zip

Click here to trigger a rebuild:
https://mir-jenkins.ubuntu.com/job/mir-ci/1798/rebuild

review: Approve (continuous-integration)

=== modified file 'tests/acceptance-tests/test_client_input.cpp'
--- tests/acceptance-tests/test_client_input.cpp	2016-06-02 08:20:22 +0000
+++ tests/acceptance-tests/test_client_input.cpp	2016-09-23 04:09:36 +0000
@@ -617,19 +617,25 @@
 
     ASSERT_THAT(input_rate, Ge(2 * frame_rate));
     ASSERT_THAT(ninputs, Gt(2 * nframes));
+
+    auto start_time = std::chrono::steady_clock::now();
+
     for (int i = 0; i < ninputs; ++i)
     {
+        /*
+         * Sleep until the correct time for the frame. We use sleep_until
+         * so that even on a very slow system it will catch up to the
+         * correct real time for the frame and not drift out causing
+         * test failures.
+         */
+        int frame_no = i / inputs_per_frame;
+        std::this_thread::sleep_until(start_time + frame_no*frame_time);
+
         int const x = i;
         int const y = 2 * i;
         fake_touch_screen->emit_event(mis::a_touch_event()
                                       .with_action(mis::TouchParameters::Action::Move)
                                       .at_position({x,y}));
-
-        // I would like to:
-        //std::this_thread::sleep_for(1000ms/input_rate);
-        // but this is more robust under Valgrind:
-        if (!((i+1) % inputs_per_frame))
-            std::this_thread::sleep_for(frame_time);
     }
 
     // Wait for the expected minimum number of events (should be quick)