Add unit tests for Rotation interpolator

include/mbgl/style/rotation.hpp

@@ -1,5 +1,5 @@
 #pragma once
-
+#include <mbgl/math/wrap.hpp>
 namespace mbgl {
 namespace style {
 
@@ -9,8 +9,8 @@ namespace style {
 class Rotation {
 public:
     Rotation() = default;
-    Rotation(double angle_) : angle(angle_) {}
-    double period() const noexcept { return 360.0; }
+    Rotation(double angle_) : angle(mbgl::util::wrap<double>(angle_, 0, period())) {}
+    constexpr double period() const noexcept { return 360.0; }
     double getAngle() const noexcept { return angle; }
 
     friend bool operator==(const Rotation& lhs, const Rotation& rhs) { return lhs.angle == rhs.angle; }

test/CMakeLists.txt

@@ -94,6 +94,7 @@ add_library(
     ${PROJECT_SOURCE_DIR}/test/util/pass.test.cpp
     ${PROJECT_SOURCE_DIR}/test/util/position.test.cpp
     ${PROJECT_SOURCE_DIR}/test/util/projection.test.cpp
+    ${PROJECT_SOURCE_DIR}/test/util/rotation.test.cpp
     ${PROJECT_SOURCE_DIR}/test/util/run_loop.test.cpp
     ${PROJECT_SOURCE_DIR}/test/util/string.test.cpp
     ${PROJECT_SOURCE_DIR}/test/util/text_conversions.test.cpp

test/util/rotation.test.cpp

@@ -0,0 +1,23 @@
+#include <mbgl/test/util.hpp>
+
+#include <mbgl/style/rotation.hpp>
+#include <mbgl/style/types.hpp>
+#include <mbgl/util/constants.hpp>
+#include <mbgl/util/interpolate.hpp>
+
+using namespace mbgl;
+using namespace style;
+
+Rotation createRotation(double angle) {
+    return Rotation(angle);
+}
+
+TEST(Rotation, Calculations) {
+    Rotation rot(42);
+    EXPECT_EQ(rot, Rotation(42 + 360));
+    Rotation rot2(-42);
+    EXPECT_EQ(rot2, Rotation(360 - 42));
+
+    mbgl::util::Interpolator<mbgl::style::Rotation> i;
+    EXPECT_NEAR(i(rot, rot2, 0.5).getAngle(), 0.0, 0.00001);
+}