[core] Fix calculation of delayed transitions

1 files changed, 94 insertions, 0 deletions

diff --git a/test/style/paint_property.test.cpp b/test/style/paint_property.test.cpp
new file mode 100644
index 0000000000..487dbe9652
--- /dev/null
+++ b/test/style/paint_property.test.cpp
@@ -0,0 +1,94 @@
+#include <mbgl/test/util.hpp>
+
+#include <mbgl/style/paint_property.hpp>
+
+using namespace mbgl;
+using namespace mbgl::style;
+using namespace std::literals::chrono_literals;
+
+TEST(UnevaluatedPaintProperty, EvaluateDefaultValue) {
+    UnevaluatedPaintProperty<float, PropertyEvaluator<float>> property;
+    ASSERT_EQ(0.0f, property.evaluate(PropertyEvaluationParameters(0), 0.0f));
+}
+
+TEST(UnevaluatedPaintProperty, EvaluateUntransitionedConstant) {
+    UnevaluatedPaintProperty<float, PropertyEvaluator<float>> property {
+        PropertyValue<float>(1.0f),
+        UnevaluatedPaintProperty<float, PropertyEvaluator<float>>(),
+        TransitionOptions(),
+        TimePoint::min()
+    };
+
+    ASSERT_EQ(1.0f, property.evaluate(PropertyEvaluationParameters(0), 0.0f));
+}
+
+TEST(UnevaluatedPaintProperty, EvaluateTransitionedConstantWithoutDelay) {
+    TransitionOptions transition;
+    transition.duration = { 1000ms };
+
+    UnevaluatedPaintProperty<float, PropertyEvaluator<float>> t0 {
+        PropertyValue<float>(0.0f),
+        UnevaluatedPaintProperty<float, PropertyEvaluator<float>>(),
+        TransitionOptions(),
+        TimePoint::min()
+    };
+
+    UnevaluatedPaintProperty<float, PropertyEvaluator<float>> t1 {
+        PropertyValue<float>(1.0f),
+        t0,
+        transition,
+        TimePoint::min()
+    };
+
+    auto evaluate = [&] (Duration delta) {
+        PropertyEvaluationParameters parameters {
+            0,
+            TimePoint::min() + delta,
+            ZoomHistory(),
+            Duration::zero()
+        };
+
+        return t1.evaluate(parameters, 0.0f);
+    };
+
+    ASSERT_FLOAT_EQ(0.0f, evaluate(0ms));
+    ASSERT_FLOAT_EQ(0.823099f, evaluate(500ms));
+    ASSERT_FLOAT_EQ(1.0f, evaluate(1500ms));
+}
+
+TEST(UnevaluatedPaintProperty, EvaluateTransitionedConstantWithDelay) {
+    TransitionOptions transition;
+    transition.delay = { 1000ms };
+    transition.duration = { 1000ms };
+
+    UnevaluatedPaintProperty<float, PropertyEvaluator<float>> t0 {
+        PropertyValue<float>(0.0f),
+        UnevaluatedPaintProperty<float, PropertyEvaluator<float>>(),
+        TransitionOptions(),
+        TimePoint::min()
+    };
+
+    UnevaluatedPaintProperty<float, PropertyEvaluator<float>> t1 {
+        PropertyValue<float>(1.0f),
+        t0,
+        transition,
+        TimePoint::min()
+    };
+
+    auto evaluate = [&] (Duration delta) {
+        PropertyEvaluationParameters parameters {
+            0,
+            TimePoint::min() + delta,
+            ZoomHistory(),
+            Duration::zero()
+        };
+
+        return t1.evaluate(parameters, 0.0f);
+    };
+
+    ASSERT_FLOAT_EQ(0.0f, evaluate(0ms));
+    ASSERT_FLOAT_EQ(0.0f, evaluate(500ms));
+    ASSERT_FLOAT_EQ(0.0f, evaluate(612ms));
+    ASSERT_FLOAT_EQ(0.823099f, evaluate(1500ms));
+    ASSERT_FLOAT_EQ(1.0f, evaluate(2500ms));
+}