Rethink Timeline test for flaky CIs.

Apparently can't even test that the returned time is in some range. So
I'll test only that the time isn't less than expected. Which it
sometimes is, on Emscripten, so add an epsilon for that as well.

src/Magnum/Test/TimelineTest.cpp

@@ -43,6 +43,16 @@ TimelineTest::TimelineTest() {
 }
 
 void TimelineTest::test() {
+    /* Can't reliably test that the measured time is less than something unless
+       we'd have the sleeps prohibitively long. So just verifying the measured
+       time isn't less than expected, and that it increases over time.
+
+       On Emscripten the returned time is however sometimes *less* than the
+       sleep, so subtracting an epsilon to account for that. */
+    constexpr std::size_t ms = 50;
+    constexpr Float s = 0.001f*ms;
+    constexpr Float epsilon = 0.01f;
+
     /* The timeline is stopped by default, so everything is zero */
     Timeline timeline;
     CORRADE_COMPARE(timeline.previousFrameTime(), 0.0f);
@@ -51,7 +61,7 @@ void TimelineTest::test() {
     CORRADE_COMPARE(timeline.currentFrameDuration(), 0.0f);
 
     /* And it continues to be 0 */
-    Utility::System::sleep(50);
+    Utility::System::sleep(ms);
     CORRADE_COMPARE(timeline.previousFrameTime(), 0.0f);
     CORRADE_COMPARE(timeline.previousFrameDuration(), 0.0f);
     CORRADE_COMPARE(timeline.currentFrameTime(), 0.0f);
@@ -63,17 +73,13 @@ void TimelineTest::test() {
     CORRADE_COMPARE(timeline.previousFrameDuration(), 0.0f);
 
     /* Still no previous frame, but current frame starts growing */
-    Utility::System::sleep(50);
+    Utility::System::sleep(ms);
     CORRADE_COMPARE(timeline.previousFrameTime(), 0.0f);
     CORRADE_COMPARE(timeline.previousFrameDuration(), 0.0f);
-    CORRADE_COMPARE_AS(timeline.currentFrameTime(), 0.05f,
+    CORRADE_COMPARE_AS(timeline.currentFrameTime(), s - epsilon,
         TestSuite::Compare::GreaterOrEqual);
-    CORRADE_COMPARE_AS(timeline.currentFrameTime(), 0.05f + 0.05f,
+    CORRADE_COMPARE_AS(timeline.currentFrameDuration(), s - epsilon,
-        TestSuite::Compare::Less);
-    CORRADE_COMPARE_AS(timeline.currentFrameDuration(), 0.05f,
         TestSuite::Compare::GreaterOrEqual);
-    CORRADE_COMPARE_AS(timeline.currentFrameDuration(), 0.05f + 0.05f,
-        TestSuite::Compare::Less);
     CORRADE_COMPARE_WITH(timeline.currentFrameTime(),
         timeline.currentFrameDuration(),
         TestSuite::Compare::around(0.01f));
@@ -82,57 +88,47 @@ void TimelineTest::test() {
     timeline.nextFrame();
     Float firstFrameTime = timeline.previousFrameTime();
     Float firstFrameDuration = timeline.previousFrameDuration();
-    CORRADE_COMPARE_AS(firstFrameTime, 0.05f,
+    CORRADE_COMPARE_AS(firstFrameTime, s - epsilon,
         TestSuite::Compare::GreaterOrEqual);
-    CORRADE_COMPARE_AS(firstFrameTime, 0.05f + 0.05f,
+    CORRADE_COMPARE_AS(firstFrameDuration, s - epsilon,
-        TestSuite::Compare::Less);
-    CORRADE_COMPARE_AS(firstFrameDuration, 0.05f,
         TestSuite::Compare::GreaterOrEqual);
-    CORRADE_COMPARE_AS(firstFrameDuration, 0.05f + 0.05f,
-        TestSuite::Compare::Less);
     CORRADE_COMPARE_AS(timeline.previousFrameDuration(),
         timeline.previousFrameTime(),
         TestSuite::Compare::LessOrEqual);
 
     /* And it doesn't change until another nextFrame() call. Current frame
        grows again. */
-    Utility::System::sleep(50);
+    Utility::System::sleep(ms);
     CORRADE_COMPARE(timeline.previousFrameTime(), firstFrameTime);
     CORRADE_COMPARE(timeline.previousFrameDuration(), firstFrameDuration);
-    CORRADE_COMPARE_AS(timeline.currentFrameTime(), 0.10f,
+    CORRADE_COMPARE_AS(timeline.currentFrameTime(), firstFrameTime,
+        TestSuite::Compare::Greater);
+    CORRADE_COMPARE_AS(timeline.currentFrameTime(), 2*s - epsilon,
         TestSuite::Compare::GreaterOrEqual);
-    CORRADE_COMPARE_AS(timeline.currentFrameTime(), 0.10f + 0.05f,
+    CORRADE_COMPARE_AS(timeline.currentFrameDuration(), s - epsilon,
-        TestSuite::Compare::Less);
-    CORRADE_COMPARE_AS(timeline.currentFrameDuration(), 0.05f,
         TestSuite::Compare::GreaterOrEqual);
-    CORRADE_COMPARE_AS(timeline.currentFrameDuration(), 0.05f + 0.05f,
-        TestSuite::Compare::Less);
 
     /* Third frame being measured now */
     timeline.nextFrame();
     Float secondFrameTime = timeline.previousFrameTime();
     Float secondFrameDuration = timeline.previousFrameDuration();
-    CORRADE_COMPARE_AS(secondFrameTime, 0.10f,
+    CORRADE_COMPARE_AS(secondFrameTime, firstFrameTime,
+        TestSuite::Compare::Greater);
+    CORRADE_COMPARE_AS(secondFrameTime, 2*s - epsilon,
         TestSuite::Compare::GreaterOrEqual);
-    CORRADE_COMPARE_AS(secondFrameTime, 0.10f + 0.05f,
+    CORRADE_COMPARE_AS(secondFrameDuration, s - epsilon,
-        TestSuite::Compare::Less);
-    CORRADE_COMPARE_AS(secondFrameDuration, 0.05f,
         TestSuite::Compare::GreaterOrEqual);
-    CORRADE_COMPARE_AS(secondFrameDuration, 0.05f + 0.05f,
-        TestSuite::Compare::Less);
 
     /* Previous frame doesn't change now either, current grows */
-    Utility::System::sleep(50);
+    Utility::System::sleep(ms);
     CORRADE_COMPARE(timeline.previousFrameTime(), secondFrameTime);
     CORRADE_COMPARE(timeline.previousFrameDuration(), secondFrameDuration);
-    CORRADE_COMPARE_AS(timeline.currentFrameTime(), 0.15f,
+    CORRADE_COMPARE_AS(timeline.currentFrameTime(), secondFrameTime,
+        TestSuite::Compare::Greater);
+    CORRADE_COMPARE_AS(timeline.currentFrameTime(), 3*s - epsilon,
         TestSuite::Compare::GreaterOrEqual);
-    CORRADE_COMPARE_AS(timeline.currentFrameTime(), 0.15f + 0.05f,
+    CORRADE_COMPARE_AS(timeline.currentFrameDuration(), s - epsilon,
-        TestSuite::Compare::Less);
-    CORRADE_COMPARE_AS(timeline.currentFrameDuration(), 0.05f,
         TestSuite::Compare::GreaterOrEqual);
-    CORRADE_COMPARE_AS(timeline.currentFrameDuration(), 0.05f + 0.05f,
-        TestSuite::Compare::Less);
 
     /* Calling start() resets the time to 0 */
     timeline.start();
@@ -140,25 +136,17 @@ void TimelineTest::test() {
     CORRADE_COMPARE(timeline.previousFrameDuration(), 0.0f);
 
     /* And it continues to be counted */
-    Utility::System::sleep(50);
+    Utility::System::sleep(ms);
-    CORRADE_COMPARE_AS(timeline.currentFrameTime(), 0.05f,
+    CORRADE_COMPARE_AS(timeline.currentFrameTime(), s - epsilon,
         TestSuite::Compare::GreaterOrEqual);
-    CORRADE_COMPARE_AS(timeline.currentFrameTime(), 0.05f + 0.05f,
+    CORRADE_COMPARE_AS(timeline.currentFrameDuration(), s - epsilon,
-        TestSuite::Compare::Less);
-    CORRADE_COMPARE_AS(timeline.currentFrameDuration(), 0.05f,
         TestSuite::Compare::GreaterOrEqual);
-    CORRADE_COMPARE_AS(timeline.currentFrameDuration(), 0.05f + 0.05f,
-        TestSuite::Compare::Less);
 
     timeline.nextFrame();
-    CORRADE_COMPARE_AS(timeline.previousFrameTime(), 0.05f,
+    CORRADE_COMPARE_AS(timeline.previousFrameTime(), s - epsilon,
         TestSuite::Compare::GreaterOrEqual);
-    CORRADE_COMPARE_AS(timeline.previousFrameTime(), 0.05f + 0.05f,
+    CORRADE_COMPARE_AS(timeline.previousFrameDuration(), s - epsilon,
-        TestSuite::Compare::Less);
-    CORRADE_COMPARE_AS(timeline.previousFrameDuration(), 0.05f,
         TestSuite::Compare::GreaterOrEqual);
-    CORRADE_COMPARE_AS(timeline.previousFrameDuration(), 0.05f + 0.05f,
-        TestSuite::Compare::Less);
     CORRADE_COMPARE_AS(timeline.previousFrameDuration(),
         timeline.previousFrameTime(),
         TestSuite::Compare::LessOrEqual);
@@ -171,7 +159,7 @@ void TimelineTest::test() {
     CORRADE_COMPARE(timeline.currentFrameDuration(), 0.0f);
 
     /* And it continues to be 0 */
-    Utility::System::sleep(50);
+    Utility::System::sleep(ms);
     timeline.nextFrame();
     CORRADE_COMPARE(timeline.previousFrameTime(), 0.0f);
     CORRADE_COMPARE(timeline.previousFrameDuration(), 0.0f);