Add test fixtures for testing raster tiles

Add a raster source for the style we use for testing that will
force requests for raster tiles.

test/fixtures/resources/source_raster.json

@@ -0,0 +1 @@
+{"attribution":"<a href=\"https://www.mapbox.com/about/maps/\" target=\"_blank\">&copy; Mapbox</a> <a href=\"http://www.openstreetmap.org/about/\" target=\"_blank\">&copy; OpenStreetMap</a> <a class=\"mapbox-improve-map\" href=\"https://www.mapbox.com/map-feedback/\" target=\"_blank\">Improve this map</a> <a href=\"https://www.digitalglobe.com/\" target=\"_blank\">&copy; DigitalGlobe</a>","autoscale":true,"bounds":[-180,-85,180,85],"center":[0,0,3],"description":"","id":"mapbox.satellite","maxzoom":19,"minzoom":0,"name":"Mapbox Satellite","private":true,"scheme":"xyz","tilejson":"2.0.0","tiles":["test/fixtures/resources/raster.png"]}

test/fixtures/resources/style.json

@@ -2,9 +2,14 @@
   "version": 1,
   "name": "Test",
   "sources": {
-    "compositedsource": {
-      "url": "test/fixtures/resources/source.json",
+    "vectorsource": {
+      "url": "test/fixtures/resources/source_vector.json",
       "type": "vector"
+    },
+    "rastersource": {
+      "url": "test/fixtures/resources/source_raster.json",
+      "type": "raster",
+      "tileSize": 256
     }
   },
   "sprite": "test/fixtures/resources/sprite",
@@ -12,7 +17,7 @@
   "layers": [{
     "id": "road",
     "type": "symbol",
-    "source": "compositedsource",
+    "source": "vectorsource",
     "source-layer": "road_label",
     "layout": {
       "text-font": "Open Sans Regular, Arial Unicode MS Regular",
@@ -21,7 +26,7 @@
   }, {
     "id": "poi",
     "type": "symbol",
-    "source": "compositedsource",
+    "source": "vectorsource",
     "source-layer": "poi_label",
     "layout": {
       "text-font": "Open Sans Regular, Arial Unicode MS Regular",