Refactor `getMetadata` tests

 - Convert promise chains to async/await

 - Add missing tests to check that the PDF URL and fingerprint URL
   appear in the object returned by `getMetadata`. These were previously
   tested indirectly in other tests.

 - Change tests to only check the specific properties of the returned
   object that are of interest. This reduces the changes needed when
   tests change unrelated parts of the output.

src/annotator/integrations/test/pdf-metadata-test.js

@@ -208,7 +208,6 @@ describe('PDFMetadata', function () {
     });
   });
 
-  describe('metadata sources', function () {
   const testMetadata = {
     fingerprint: 'fakeFingerprint',
     title: 'fakeTitle',
@@ -262,69 +261,58 @@ describe('PDFMetadata', function () {
     });
   });
 
-    describe('#getMetadata', function () {
-      it('gets the title from the dc:title field', function () {
-        const { fakePDFViewerApplication, pdfMetadata } = createPDFMetadata();
-        const expectedMetadata = {
-          title: 'dcFakeTitle',
-          link: [
-            {
-              href:
-                'urn:x-pdf:' + fakePDFViewerApplication.pdfDocument.fingerprint,
-            },
-            { href: fakePDFViewerApplication.url },
-          ],
-          documentFingerprint: fakePDFViewerApplication.pdfDocument.fingerprint,
-        };
+  describe('#getMetadata', () => {
+    it('returns the document fingerprint in the `documentFingerprint` property', async () => {
+      const { pdfMetadata } = createPDFMetadata();
+      const metadata = await pdfMetadata.getMetadata();
+      assert.equal(metadata.documentFingerprint, testMetadata.fingerprint);
+    });
 
-        return pdfMetadata.getMetadata().then(function (actualMetadata) {
-          assert.deepEqual(actualMetadata, expectedMetadata);
+    it('returns the PDF URL in the `links` array', async () => {
+      const { pdfMetadata } = createPDFMetadata();
+      const metadata = await pdfMetadata.getMetadata();
+      assert.deepInclude(metadata.link, {
+        href: testMetadata.url,
       });
     });
 
-      it('gets the title from the documentInfo.Title field', function () {
-        const { fakePDFViewerApplication, pdfMetadata } = createPDFMetadata();
-        const expectedMetadata = {
-          title: fakePDFViewerApplication.documentInfo.Title,
-          link: [
-            {
-              href:
-                'urn:x-pdf:' + fakePDFViewerApplication.pdfDocument.fingerprint,
-            },
-            { href: fakePDFViewerApplication.url },
-          ],
-          documentFingerprint: fakePDFViewerApplication.pdfDocument.fingerprint,
-        };
-
-        fakePDFViewerApplication.metadata.has = sinon.stub().returns(false);
-
-        return pdfMetadata.getMetadata().then(function (actualMetadata) {
-          assert.deepEqual(actualMetadata, expectedMetadata);
+    it('returns the document fingerprint in the `links` array', async () => {
+      const { pdfMetadata } = createPDFMetadata();
+      const metadata = await pdfMetadata.getMetadata();
+      assert.deepInclude(metadata.link, {
+        href: `urn:x-pdf:${testMetadata.fingerprint}`,
       });
     });
 
-      it('does not save file:// URLs in document metadata', function () {
-        const { fakePDFViewerApplication, pdfMetadata } = createPDFMetadata({
+    it('does not return file:// URLs in `links` array', async () => {
+      const { pdfMetadata } = createPDFMetadata({
         fingerprint: 'fakeFingerprint',
         url: 'file://fake.pdf',
       });
-        const expectedMetadata = {
-          link: [
-            {
-              href:
-                'urn:x-pdf:' + fakePDFViewerApplication.pdfDocument.fingerprint,
-            },
-          ],
-        };
 
-        return pdfMetadata.getMetadata().then(function (actualMetadata) {
-          assert.equal(actualMetadata.link.length, 1);
-          assert.equal(
-            actualMetadata.link[0].href,
-            expectedMetadata.link[0].href
+      const metadata = await pdfMetadata.getMetadata();
+
+      const fileLink = metadata.link.find(link =>
+        link.href.includes('file://')
       );
+      assert.isUndefined(fileLink);
     });
+
+    it('gets the title from the dc:title field', async () => {
+      const { pdfMetadata } = createPDFMetadata();
+      const metadata = await pdfMetadata.getMetadata();
+      assert.equal(metadata.title, testMetadata.metadata['dc:title']);
     });
+
+    it('gets the title from the documentInfo.Title field', async () => {
+      const { pdfMetadata } = createPDFMetadata({
+        title: 'Some title',
+        url: 'http://fake.com/',
+      });
+
+      const metadata = await pdfMetadata.getMetadata();
+
+      assert.equal(metadata.title, 'Some title');
     });
   });
 });