Add a basic test for Timeline functionality.

It took me over a decade to realize I could just test as greater / less
instead of equality. HAHA.

src/Magnum/Test/CMakeLists.txt

@@ -41,6 +41,7 @@ corrade_add_test(ResourceManagerTest ResourceManagerTest.cpp LIBRARIES Magnum)
 corrade_add_test(SamplerTest SamplerTest.cpp LIBRARIES MagnumTestLib)
 # Prefixed with project name to avoid conflicts with TagsTest in Corrade
 corrade_add_test(MagnumTagsTest TagsTest.cpp LIBRARIES Magnum)
+corrade_add_test(TimelineTest TimelineTest.cpp LIBRARIES Magnum)
 
 # Prefixed with project name to avoid conflicts with VersionTest in Corrade and
 # other repos

src/Magnum/Test/TimelineTest.cpp

@@ -0,0 +1,139 @@
+/*
+    This file is part of Magnum.
+
+    Copyright © 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019,
+                2020, 2021, 2022 Vladimír Vondruš <mosra@centrum.cz>
+
+    Permission is hereby granted, free of charge, to any person obtaining a
+    copy of this software and associated documentation files (the "Software"),
+    to deal in the Software without restriction, including without limitation
+    the rights to use, copy, modify, merge, publish, distribute, sublicense,
+    and/or sell copies of the Software, and to permit persons to whom the
+    Software is furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be included
+    in all copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+    THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+    DEALINGS IN THE SOFTWARE.
+*/
+
+#include <Corrade/TestSuite/Tester.h>
+#include <Corrade/TestSuite/Compare/Numeric.h>
+#include <Corrade/Utility/System.h>
+
+#include "Magnum/Magnum.h"
+#include "Magnum/Timeline.h"
+
+namespace Magnum { namespace Test { namespace {
+
+struct TimelineTest: TestSuite::Tester {
+    explicit TimelineTest();
+
+    void test();
+};
+
+TimelineTest::TimelineTest() {
+    addTests({&TimelineTest::test});
+}
+
+void TimelineTest::test() {
+    /* The timeline is stopped by default, so everything is zero */
+    Timeline timeline;
+    CORRADE_COMPARE(timeline.previousFrameTime(), 0.0f);
+    CORRADE_COMPARE(timeline.previousFrameDuration(), 0.0f);
+
+    /* And it continues to be 0 */
+    Utility::System::sleep(50);
+    CORRADE_COMPARE(timeline.previousFrameTime(), 0.0f);
+    CORRADE_COMPARE(timeline.previousFrameDuration(), 0.0f);
+
+    /* There's no previous frame right after the start */
+    timeline.start();
+    CORRADE_COMPARE(timeline.previousFrameTime(), 0.0f);
+    CORRADE_COMPARE(timeline.previousFrameDuration(), 0.0f);
+
+    /* Still no previous frame */
+    Utility::System::sleep(50);
+    CORRADE_COMPARE(timeline.previousFrameTime(), 0.0f);
+    CORRADE_COMPARE(timeline.previousFrameDuration(), 0.0f);
+
+    /* Now it is */
+    timeline.nextFrame();
+    Float firstFrameTime = timeline.previousFrameTime();
+    Float firstFrameDuration = timeline.previousFrameDuration();
+    CORRADE_COMPARE_AS(firstFrameTime, 0.05f,
+        TestSuite::Compare::GreaterOrEqual);
+    CORRADE_COMPARE_AS(firstFrameTime, 0.05f + 0.05f,
+        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 */
+    Utility::System::sleep(50);
+    CORRADE_COMPARE(timeline.previousFrameTime(), firstFrameTime);
+    CORRADE_COMPARE(timeline.previousFrameDuration(), firstFrameDuration);
+
+    /* Third frame being measured now */
+    timeline.nextFrame();
+    Float secondFrameTime = timeline.previousFrameTime();
+    Float secondFrameDuration = timeline.previousFrameDuration();
+    CORRADE_COMPARE_AS(secondFrameTime, 0.10f,
+        TestSuite::Compare::GreaterOrEqual);
+    CORRADE_COMPARE_AS(secondFrameTime, 0.10f + 0.05f,
+        TestSuite::Compare::Less);
+    CORRADE_COMPARE_AS(secondFrameDuration, 0.05f,
+        TestSuite::Compare::GreaterOrEqual);
+    CORRADE_COMPARE_AS(secondFrameDuration, 0.05f + 0.05f,
+        TestSuite::Compare::Less);
+
+    /* And it doesn't change now either */
+    Utility::System::sleep(50);
+    CORRADE_COMPARE(timeline.previousFrameTime(), secondFrameTime);
+    CORRADE_COMPARE(timeline.previousFrameDuration(), secondFrameDuration);
+
+    /* Calling start() resets the time to 0 */
+    timeline.start();
+    CORRADE_COMPARE(timeline.previousFrameTime(), 0.0f);
+    CORRADE_COMPARE(timeline.previousFrameDuration(), 0.0f);
+
+    /* And it continues to be counted */
+    Utility::System::sleep(50);
+    timeline.nextFrame();
+    CORRADE_COMPARE_AS(timeline.previousFrameTime(), 0.05f,
+        TestSuite::Compare::GreaterOrEqual);
+    CORRADE_COMPARE_AS(timeline.previousFrameTime(), 0.05f + 0.05f,
+        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);
+
+    /* Calling stop() resets the time to 0 */
+    timeline.stop();
+    CORRADE_COMPARE(timeline.previousFrameTime(), 0.0f);
+    CORRADE_COMPARE(timeline.previousFrameDuration(), 0.0f);
+
+    /* And it continues to be 0 */
+    Utility::System::sleep(50);
+    timeline.nextFrame();
+    CORRADE_COMPARE(timeline.previousFrameTime(), 0.0f);
+    CORRADE_COMPARE(timeline.previousFrameDuration(), 0.0f);
+}
+
+}}}
+
+CORRADE_TEST_MAIN(Magnum::Test::TimelineTest)