Leaflet/spec/suites/layer/tile/TileLayerSpec.js

describe('TileLayer', function () {
	var tileUrl = '',
		map;

	beforeEach(function () {
		map = L.map(document.createElement('div'));
	});

	describe("#onAdd", function () {
		it('is called after viewreset on first map load', function () {
			var layer = L.tileLayer(tileUrl).addTo(map);

			var onAdd = layer.onAdd,
				onAddSpy = sinon.spy();
			layer.onAdd = function () {
				onAdd.apply(this, arguments);
				onAddSpy();
			};

			var onReset = sinon.spy();
			map.on('viewreset', onReset);
			map.setView([0, 0], 0);

			expect(onReset.calledBefore(onAddSpy)).to.be.ok();
		});
	});

	describe("#getMaxZoom, #getMinZoom", function () {
		describe("when a tilelayer is added to a map with no other layers", function () {
			it("has the same zoomlevels as the tilelayer", function () {
				var maxZoom = 10,
					minZoom = 5;

				map.setView([0, 0], 1);

				L.tileLayer(tileUrl, {
					maxZoom: maxZoom,
					minZoom: minZoom
				}).addTo(map);

				expect(map.getMaxZoom()).to.be(maxZoom);
				expect(map.getMinZoom()).to.be(minZoom);
			});
		});

		describe("accessing a tilelayer's properties", function () {
			it('provides a container', function () {
				map.setView([0, 0], 1);

				var layer = L.tileLayer(tileUrl).addTo(map);
				expect(layer.getContainer()).to.be.ok();
			});
		});

		describe("when a tilelayer is added to a map that already has a tilelayer", function () {
			it("has its zoomlevels updated to fit the new layer", function () {
				map.setView([0, 0], 1);

				L.tileLayer(tileUrl, {minZoom: 10, maxZoom: 15}).addTo(map);
				expect(map.getMinZoom()).to.be(10);
				expect(map.getMaxZoom()).to.be(15);

				L.tileLayer(tileUrl, {minZoom: 5, maxZoom: 10}).addTo(map);
				expect(map.getMinZoom()).to.be(5);  // changed
				expect(map.getMaxZoom()).to.be(15); // unchanged

				L.tileLayer(tileUrl, {minZoom: 10, maxZoom: 20}).addTo(map);
				expect(map.getMinZoom()).to.be(5);  // unchanged
				expect(map.getMaxZoom()).to.be(20); // changed


				L.tileLayer(tileUrl, {minZoom: 0, maxZoom: 25}).addTo(map);
				expect(map.getMinZoom()).to.be(0); // changed
				expect(map.getMaxZoom()).to.be(25); // changed
			});
		});
		describe("when a tilelayer is removed from a map", function () {
			it("has its zoomlevels updated to only fit the layers it currently has", function () {
				var tiles = [  L.tileLayer(tileUrl, {minZoom: 10, maxZoom: 15}).addTo(map),
							   L.tileLayer(tileUrl, {minZoom: 5, maxZoom: 10}).addTo(map),
							   L.tileLayer(tileUrl, {minZoom: 10, maxZoom: 20}).addTo(map),
							   L.tileLayer(tileUrl, {minZoom: 0, maxZoom: 25}).addTo(map)
							];
				map.whenReady(function () {
					expect(map.getMinZoom()).to.be(0);
					expect(map.getMaxZoom()).to.be(25);

					map.removeLayer(tiles[0]);
					expect(map.getMinZoom()).to.be(0);
					expect(map.getMaxZoom()).to.be(25);

					map.removeLayer(tiles[3]);
					expect(map.getMinZoom()).to.be(5);
					expect(map.getMaxZoom()).to.be(20);

					map.removeLayer(tiles[2]);
					expect(map.getMinZoom()).to.be(5);
					expect(map.getMaxZoom()).to.be(10);

					map.removeLayer(tiles[1]);
					expect(map.getMinZoom()).to.be(0);
					expect(map.getMaxZoom()).to.be(Infinity);
				});
			});
		});
	});

	describe("'loading' event", function() {
		var tileUrl1 = 'http://{s}.tile.osm.org/{z}/{x}/{y}.png',
			tileUrl2 = 'http://{s}.tile.stamen.com/toner/{z}/{x}/{y}.png';

		// Inject Leaflet css
		var head = document.getElementsByTagName("head")[0],
			link = document.createElement("link");
		link.href = "../dist/leaflet.css";
		link.type = "text/css";
		link.rel = "stylesheet";
		head.appendChild(link);

		// Add map div to DOM. The map panning tests do not work reliably unless
		// the Leaflet map is properly styled and part of the DOM
		var mapDiv = document.createElement('div');
		mapDiv.style.height = '256px';
		mapDiv.style.width = '256px';
		document.body.appendChild(mapDiv);

		this.afterAll(function() {
			document.body.removeChild(mapDiv);
		});

		// Set the map zoom high enough that panning by 256 pixels necessarily loads more tiles
		var myMap = L.map(mapDiv).setView([0, 0], 13);
		
		describe("after a tilelayer has been initialized with an empty string", function() {
			var layer = L.tileLayer('');
			var updateInterval = layer.options.updateInterval + 500;

			var loadingSpy;
			beforeEach(function() {
				loadingSpy = sinon.spy();
				layer.on('loading', function() { loadingSpy(); });
			});
			afterEach(function() {
				layer.off('loading');
			});

			it("is fired when the tilelayer is added to the map", function() {
				layer.addTo(myMap);
				expect(loadingSpy.calledOnce).to.be.ok();
			});

			it("is fired again when the tilelayer has its url set to a real tile url", function(done) {
				layer.setUrl(tileUrl2);
				
				setTimeout(function() {
					expect(loadingSpy.calledOnce).to.be.ok();
					done();
				}, updateInterval);
			});

			it("is fired again when the map is panned enough to load more tiles", function(done) {
				myMap.panBy([256,256]);
				
				setTimeout(function() {
					expect(loadingSpy.calledOnce).to.be.ok();
					done();
				}, updateInterval);
			});
		});

		describe("after a tilelayer has been initialized with a real tile url", function() {
			var layer = L.tileLayer(tileUrl1);
			var updateInterval = layer.options.updateInterval + 500;

			var loadingSpy;
			beforeEach(function() {
				loadingSpy = sinon.spy();
				layer.on('loading', function() { loadingSpy(); });
			});
			afterEach(function() {
				layer.off('loading');
			});

			it("is fired when the tilelayer is added to the map", function() {
				layer.addTo(myMap);
				expect(loadingSpy.calledOnce).to.be.ok();
			});

			it("is fired again when the tilelayer has its url set to a real tile url", function(done) {
				layer.setUrl(tileUrl2);
				
				setTimeout(function() {
					expect(loadingSpy.calledOnce).to.be.ok();
					done();
				}, updateInterval);
			});

			it("is fired again when the map is panned enough to load more tiles", function(done) {
				myMap.panBy([256,256]);
				
				setTimeout(function() {
					expect(loadingSpy.calledOnce).to.be.ok();
					done();
				}, updateInterval);
			});
		});
	});

});