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test/unit/canvas_factory_spec.js

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+/* Copyright 2017 Mozilla Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { DOMCanvasFactory } from "../../src/display/canvas_factory.js";
+import { isNodeJS } from "../../src/shared/util.js";
+
+describe("canvas_factory", function () {
+  describe("DOMCanvasFactory", function () {
+    let canvasFactory;
+
+    beforeAll(function () {
+      canvasFactory = new DOMCanvasFactory({});
+    });
+
+    afterAll(function () {
+      canvasFactory = null;
+    });
+
+    it("`create` should throw an error if the dimensions are invalid", function () {
+      // Invalid width.
+      expect(function () {
+        return canvasFactory.create(-1, 1);
+      }).toThrow(new Error("Invalid canvas size"));
+
+      // Invalid height.
+      expect(function () {
+        return canvasFactory.create(1, -1);
+      }).toThrow(new Error("Invalid canvas size"));
+    });
+
+    it("`create` should return a canvas if the dimensions are valid", function () {
+      if (isNodeJS) {
+        pending("Document is not supported in Node.js.");
+      }
+
+      const { canvas, context } = canvasFactory.create(20, 40);
+      expect(canvas instanceof HTMLCanvasElement).toBe(true);
+      expect(context instanceof CanvasRenderingContext2D).toBe(true);
+      expect(canvas.width).toBe(20);
+      expect(canvas.height).toBe(40);
+    });
+
+    it("`reset` should throw an error if no canvas is provided", function () {
+      const canvasAndContext = { canvas: null, context: null };
+
+      expect(function () {
+        return canvasFactory.reset(canvasAndContext, 20, 40);
+      }).toThrow(new Error("Canvas is not specified"));
+    });
+
+    it("`reset` should throw an error if the dimensions are invalid", function () {
+      const canvasAndContext = { canvas: "foo", context: "bar" };
+
+      // Invalid width.
+      expect(function () {
+        return canvasFactory.reset(canvasAndContext, -1, 1);
+      }).toThrow(new Error("Invalid canvas size"));
+
+      // Invalid height.
+      expect(function () {
+        return canvasFactory.reset(canvasAndContext, 1, -1);
+      }).toThrow(new Error("Invalid canvas size"));
+    });
+
+    it("`reset` should alter the canvas/context if the dimensions are valid", function () {
+      if (isNodeJS) {
+        pending("Document is not supported in Node.js.");
+      }
+
+      const canvasAndContext = canvasFactory.create(20, 40);
+      canvasFactory.reset(canvasAndContext, 60, 80);
+
+      const { canvas, context } = canvasAndContext;
+      expect(canvas instanceof HTMLCanvasElement).toBe(true);
+      expect(context instanceof CanvasRenderingContext2D).toBe(true);
+      expect(canvas.width).toBe(60);
+      expect(canvas.height).toBe(80);
+    });
+
+    it("`destroy` should throw an error if no canvas is provided", function () {
+      expect(function () {
+        return canvasFactory.destroy({});
+      }).toThrow(new Error("Canvas is not specified"));
+    });
+
+    it("`destroy` should clear the canvas/context", function () {
+      if (isNodeJS) {
+        pending("Document is not supported in Node.js.");
+      }
+
+      const canvasAndContext = canvasFactory.create(20, 40);
+      canvasFactory.destroy(canvasAndContext);
+
+      const { canvas, context } = canvasAndContext;
+      expect(canvas).toBe(null);
+      expect(context).toBe(null);
+    });
+  });
+});