Handle extracted comments in headers

test/fixtures/comment.po

@@ -1,6 +1,7 @@
 # French translation of Link (6.x-2.9)
 # Copyright (c) 2011 by the French translation team
 #
+#. extracted from test
 msgid ""
 msgstr ""
 "Project-Id-Version: Link (6.x-2.9)\n"

test/parse.js

@@ -61,6 +61,9 @@ describe('Parse', function () {
         assert.notEqual(po, null);
         assert.equal(po.items.length, 2);
 
+        assert.equal(po.extractedComments.length, 1);
+        assert.equal(po.extractedComments[0], 'extracted from test');
+
         var item = po.items[0];
         assert.equal(item.msgid, 'Title, as plain text');
         assert.equal(item.msgstr, 'Attribut title, en tant que texte brut');

test/write.js

@@ -74,6 +74,7 @@ describe('Write', function () {
         var input = fs.readFileSync(__dirname + '/fixtures/comment.po', 'utf8');
         var po = PO.parse(input);
         var str = po.toString();
+        assertHasLine(str, '#. extracted from test');
         assertHasLine(str, '#. Extracted comment');
     });