Add a new DOMFileReaderFactory helper to the unit-tests, and re-factor NodeFileReaderFactory to be asynchronous

This allows simplification of the 'creates pdf doc from URL and aborts loading after worker initialized' API unit-test.

Note that the `DOMFileReaderFactory` uses the Fetch API, for simplicity, since it should be available in all browsers where we're running tests.

test/unit/api_spec.js

@@ -14,13 +14,12 @@
  */
 
 import {
-  buildGetDocumentParams, NodeCanvasFactory, NodeFileReaderFactory,
-  TEST_PDFS_PATH
+  buildGetDocumentParams, DOMFileReaderFactory, NodeCanvasFactory,
+  NodeFileReaderFactory, TEST_PDFS_PATH
 } from './test_utils';
 import {
   createPromiseCapability, FontType, InvalidPDFException, MissingPDFException,
-  OPS, PasswordException, PasswordResponses, PermissionFlag, StreamType,
-  stringToBytes
+  OPS, PasswordException, PasswordResponses, PermissionFlag, StreamType
 } from '../../src/shared/util';
 import {
   DOMCanvasFactory, RenderingCancelledException, StatTimer
@@ -110,50 +109,37 @@ describe('api', function() {
       }).catch(done.fail);
     });
     it('creates pdf doc from typed array', function(done) {
-      var typedArrayPdf;
+      let typedArrayPdfPromise;
       if (isNodeJS()) {
-        typedArrayPdf = NodeFileReaderFactory.fetch({
+        typedArrayPdfPromise = NodeFileReaderFactory.fetch({
           path: TEST_PDFS_PATH.node + basicApiFileName,
         });
       } else {
-        let nonBinaryRequest = false;
-        let request = new XMLHttpRequest();
-        request.open('GET', TEST_PDFS_PATH.dom + basicApiFileName, false);
-        try {
-          request.responseType = 'arraybuffer';
-          nonBinaryRequest = request.responseType !== 'arraybuffer';
-        } catch (e) {
-          nonBinaryRequest = true;
-        }
-        if (nonBinaryRequest && request.overrideMimeType) {
-          request.overrideMimeType('text/plain; charset=x-user-defined');
-        }
-        request.send(null);
-
-        if (nonBinaryRequest) {
-          typedArrayPdf = stringToBytes(request.responseText);
-        } else {
-          typedArrayPdf = new Uint8Array(request.response);
-        }
+        typedArrayPdfPromise = DOMFileReaderFactory.fetch({
+          path: TEST_PDFS_PATH.dom + basicApiFileName,
+        });
       }
-      // Sanity check to make sure that we fetched the entire PDF file.
-      expect(typedArrayPdf.length).toEqual(basicApiFileLength);
 
-      const loadingTask = getDocument(typedArrayPdf);
+      typedArrayPdfPromise.then((typedArrayPdf) => {
+        // Sanity check to make sure that we fetched the entire PDF file.
+        expect(typedArrayPdf.length).toEqual(basicApiFileLength);
 
-      const progressReportedCapability = createPromiseCapability();
-      loadingTask.onProgress = function(data) {
-        progressReportedCapability.resolve(data);
-      };
+        const loadingTask = getDocument(typedArrayPdf);
 
-      Promise.all([
-        loadingTask.promise,
-        progressReportedCapability.promise,
-      ]).then(function(data) {
-        expect(data[0] instanceof PDFDocumentProxy).toEqual(true);
-        expect(data[1].loaded / data[1].total).toEqual(1);
+        const progressReportedCapability = createPromiseCapability();
+        loadingTask.onProgress = function(data) {
+          progressReportedCapability.resolve(data);
+        };
 
-        loadingTask.destroy().then(done);
+        return Promise.all([
+          loadingTask.promise,
+          progressReportedCapability.promise,
+        ]).then(function(data) {
+          expect(data[0] instanceof PDFDocumentProxy).toEqual(true);
+          expect(data[1].loaded / data[1].total).toEqual(1);
+
+          loadingTask.destroy().then(done);
+        });
       }).catch(done.fail);
     });
     it('creates pdf doc from invalid PDF file', function(done) {

test/unit/test_utils.js

@@ -17,11 +17,29 @@ import { assert, CMapCompressionType } from '../../src/shared/util';
 import isNodeJS from '../../src/shared/is_node';
 import { isRef } from '../../src/core/primitives';
 
+class DOMFileReaderFactory {
+  static async fetch(params) {
+    const response = await fetch(params.path);
+    if (!response.ok) {
+      throw new Error(response.statusText);
+    }
+    return new Uint8Array(await response.arrayBuffer());
+  }
+}
+
 class NodeFileReaderFactory {
-  static fetch(params) {
-    var fs = require('fs');
-    var file = fs.readFileSync(params.path);
-    return new Uint8Array(file);
+  static async fetch(params) {
+    const fs = require('fs');
+
+    return new Promise((resolve, reject) => {
+      fs.readFile(params.path, (error, data) => {
+        if (error || !data) {
+          reject(error || new Error(`Empty file for: ${params.path}`));
+          return;
+        }
+        resolve(new Uint8Array(data));
+      });
+    });
   }
 }
 
@@ -142,6 +160,7 @@ class XRefMock {
 }
 
 export {
+  DOMFileReaderFactory,
   NodeFileReaderFactory,
   NodeCanvasFactory,
   NodeCMapReaderFactory,