[test] Added Projection tests

2 files changed, 69 insertions, 0 deletions

diff --git a/test/test.gypi b/test/test.gypi
index b7e7b5c32b..d93ecd1f35 100644
--- a/test/test.gypi
+++ b/test/test.gypi
@@ -32,6 +32,7 @@
         'util/timer.cpp',
         'util/token.cpp',
         'util/work_queue.cpp',
+        'util/projection.cpp',
 
         'algorithm/covered_by_children.cpp',
         'algorithm/generate_clip_ids.cpp',
diff --git a/test/util/projection.cpp b/test/util/projection.cpp
new file mode 100644
index 0000000000..5efba380b3
--- /dev/null
+++ b/test/util/projection.cpp
@@ -0,0 +1,68 @@
+#include <mbgl/test/util.hpp>
+
+#include <mbgl/util/constants.hpp>
+#include <mbgl/util/geo.hpp>
+#include <mbgl/util/projection.hpp>
+
+#include <limits>
+
+using namespace mbgl;
+
+TEST(Projection, MetersPerPixelAtLatitude) {
+    double zoom = 0;
+    EXPECT_DOUBLE_EQ(Projection::getMetersPerPixelAtLatitude(0, zoom), 78271.516964020484);
+    EXPECT_DOUBLE_EQ(Projection::getMetersPerPixelAtLatitude(-util::LATITUDE_MAX, zoom), 6752.2284729446501);
+    EXPECT_DOUBLE_EQ(Projection::getMetersPerPixelAtLatitude(util::LATITUDE_MAX, zoom),
+                     Projection::getMetersPerPixelAtLatitude(-util::LATITUDE_MAX, zoom));
+
+    zoom = 20;
+    EXPECT_DOUBLE_EQ(Projection::getMetersPerPixelAtLatitude(0, zoom), 0.074645535434742435);
+    EXPECT_DOUBLE_EQ(Projection::getMetersPerPixelAtLatitude(-util::LATITUDE_MAX, zoom), 0.0064394268731543065);
+
+    EXPECT_DOUBLE_EQ(Projection::getMetersPerPixelAtLatitude(std::numeric_limits<double>::lowest(), zoom),
+                     Projection::getMetersPerPixelAtLatitude(std::numeric_limits<double>::max(), zoom));
+
+    zoom = std::numeric_limits<double>::min();
+    EXPECT_DOUBLE_EQ(Projection::getMetersPerPixelAtLatitude(0, zoom),
+                     Projection::getMetersPerPixelAtLatitude(0, util::MIN_ZOOM));
+
+    zoom = std::numeric_limits<double>::lowest();
+    EXPECT_DOUBLE_EQ(Projection::getMetersPerPixelAtLatitude(0, zoom),
+                     Projection::getMetersPerPixelAtLatitude(0, util::MIN_ZOOM));
+
+    zoom = std::numeric_limits<double>::max();
+    EXPECT_DOUBLE_EQ(Projection::getMetersPerPixelAtLatitude(0, zoom),
+                     Projection::getMetersPerPixelAtLatitude(0, util::MAX_ZOOM));
+}
+
+TEST(Projection, ProjectedMeters) {
+    const auto southWest = LatLng { -util::LATITUDE_MAX, -util::LONGITUDE_MAX };
+    const auto northEast = LatLng { util::LATITUDE_MAX, util::LONGITUDE_MAX };
+
+    auto latLng = LatLng {};
+    auto projectedMeters = Projection::projectedMetersForLatLng(latLng);
+    EXPECT_EQ(projectedMeters.northing, projectedMeters.easting);
+    EXPECT_EQ(latLng, Projection::latLngForProjectedMeters(projectedMeters));
+
+    latLng = LatLng { std::numeric_limits<double>::lowest(), std::numeric_limits<double>::lowest() };
+    projectedMeters = Projection::projectedMetersForLatLng(latLng);
+    EXPECT_EQ(projectedMeters, Projection::projectedMetersForLatLng(southWest));
+    EXPECT_DOUBLE_EQ(projectedMeters.northing, -20037508.342789274);
+    EXPECT_DOUBLE_EQ(projectedMeters.easting, -20037508.342789244);
+
+    latLng = LatLng { std::numeric_limits<double>::max(), std::numeric_limits<double>::max() };
+    projectedMeters = Projection::projectedMetersForLatLng(latLng);
+    EXPECT_EQ(projectedMeters, Projection::projectedMetersForLatLng(northEast));
+    EXPECT_DOUBLE_EQ(projectedMeters.northing, -Projection::projectedMetersForLatLng(southWest).northing);
+    EXPECT_DOUBLE_EQ(projectedMeters.easting, -Projection::projectedMetersForLatLng(southWest).easting);
+
+    projectedMeters = ProjectedMeters { std::numeric_limits<double>::lowest(), std::numeric_limits<double>::lowest() };
+    latLng = Projection::latLngForProjectedMeters(projectedMeters);
+    EXPECT_EQ(latLng.latitude, -util::LATITUDE_MAX);
+    EXPECT_EQ(latLng.longitude, -util::LONGITUDE_MAX);
+
+    projectedMeters = ProjectedMeters { std::numeric_limits<double>::max(), std::numeric_limits<double>::max() };
+    latLng = Projection::latLngForProjectedMeters(projectedMeters);
+    EXPECT_EQ(latLng.latitude, util::LATITUDE_MAX);
+    EXPECT_EQ(latLng.longitude, util::LONGITUDE_MAX);
+}