add unit tests to cover various code paths in _updateMapTransform()

Author: NathanMOlson

src/ui/handler/scroll_zoom.test.ts

@@ -297,6 +297,58 @@ describe('ScrollZoomHandler', () => {
 
     });
 
+    test('Zooms for single mouse wheel tick while in the center of the map, should zoom to center', () => {
+        const browserNow = jest.spyOn(browser, 'now');
+        let now = 1555555555555;
+        browserNow.mockReturnValue(now);
+
+        const map = createMap();
+        map._renderTaskQueue.run();
+        expect(map.getCenter().lat).toBeCloseTo(0, 10);
+        expect(map.getCenter().lng).toBeCloseTo(0, 10);
+
+        // simulate a single 'wheel' event
+        simulate.wheel(map.getCanvas(), {type: 'wheel', deltaY: -simulate.magicWheelZoomDelta, clientX: 200, clientY: 150});
+        map._renderTaskQueue.run();
+
+        now += 400;
+        browserNow.mockReturnValue(now);
+        map._renderTaskQueue.run();
+
+        expect(map.getCenter().lat).toBeCloseTo(0, 10);
+        expect(map.getCenter().lng).toBeCloseTo(0, 10);
+        expect(map.getZoom()).toBeCloseTo(0.028567106927402726, 10);
+
+        map.remove();
+    });
+
+    test('Zooms for single mouse wheel tick while not in the center of the map, should zoom according to mouse position', () => {
+        const browserNow = jest.spyOn(browser, 'now');
+        let now = 1555555555555;
+        browserNow.mockReturnValue(now);
+
+        const map = createMap();
+        map._elevateCameraIfInsideTerrain = (_tr : any) => ({});
+        map._renderTaskQueue.run();
+        map.terrain = {
+            pointCoordinate: () => null
+        } as any;
+
+        // simulate a single 'wheel' event
+        simulate.wheel(map.getCanvas(), {type: 'wheel', deltaY: -simulate.magicWheelZoomDelta, clientX: 1000, clientY: 1000});
+        map._renderTaskQueue.run();
+
+        now += 400;
+        browserNow.mockReturnValue(now);
+        map._renderTaskQueue.run();
+
+        expect(map.getCenter().lat).toBeCloseTo(-11.6371, 3);
+        expect(map.getCenter().lng).toBeCloseTo(11.0286, 3);
+        expect(map.getZoom()).toBeCloseTo(0.028567106927402726, 10);
+
+        map.remove();
+    });
+
     test('Zooms for single mouse wheel tick while not in the center of the map and terrain is on, should zoom according to mouse position', () => {
         const browserNow = jest.spyOn(browser, 'now');
         let now = 1555555555555;

src/ui/map_tests/map_events.test.ts

@@ -975,6 +975,30 @@ describe('map events', () => {
         expect(actualZoom).toBe(map.getZoom());
     });
 
+    test('drag from center', () => {
+        const map = createMap({interactive: true, clickTolerance: 4});
+        map.on('moveend', () => {
+            expect(map.getCenter().lng).toBeCloseTo(0, 10);
+            expect(map.getCenter().lat).toBeCloseTo(33.13755119234696, 10);
+            expect(map.getCenterElevation()).toBeCloseTo(0, 10);
+        });
+        const canvas = map.getCanvas();
+        simulate.dragWithMove(canvas, {x: 100, y: 100}, {x: 100, y: 150});
+        map._renderTaskQueue.run();
+    });
+
+    test('drag from off center', () => {
+        const map = createMap({interactive: true, clickTolerance: 4});
+        map.on('moveend', () => {
+            expect(map.getCenter().lng).toBeCloseTo(0, 10);
+            expect(map.getCenter().lat).toBeCloseTo(33.13755119234696, 10);
+            expect(map.getCenterElevation()).toBeCloseTo(0, 10);
+        });
+        const canvas = map.getCanvas();
+        simulate.dragWithMove(canvas, {x: 50, y: 50}, {x: 50, y: 100});
+        map._renderTaskQueue.run();
+    });
+
     describe('error event', () => {
         test('logs errors to console when it has NO listeners', () => {
             // to avoid seeing error in the console in Jest