new implementation of items marked obsolete

the current implementation of items marked obsolete did not allow "plain"
comments for these items. However, this is perfectly fine according to
the original gettext tools. When writing a po file, comments for obsolete
items don't contain the '#~ ' mark (tested using msgcat), so this is now
also aligned with the behaviour of the original gettext tools.

For all these cases I added examples in the po files, that failed with the
current implementation and work fine after these changes.

test/fixtures/commented.po

@@ -21,3 +21,13 @@ msgstr "{{dataLoader.data.length}} resultaten"
 
 #~ msgid "Add order"
 #~ msgstr "Order toevoegen"
+
+#~ # commented obsolete item
+#~ #, fuzzy
+#~ msgid "Commented item"
+#~ msgstr "not sure"
+
+# commented obsolete item
+#, fuzzy
+#~ msgid "Second commented item"
+#~ msgstr "also not sure"

test/parse.js

@@ -96,7 +96,7 @@ describe('Parse', function () {
     it('Handles obsolete items', function () {
         var po = PO.parse(fs.readFileSync(__dirname + '/fixtures/commented.po', 'utf8'));
 
-        assert.equal(po.items.length, 2);
+        assert.equal(po.items.length, 4);
         var item = po.items[0];
         assert.equal(item.obsolete, false);
         assert.equal(item.msgid, '{{dataLoader.data.length}} results');
@@ -106,6 +106,16 @@ describe('Parse', function () {
         assert.equal(item.obsolete, true);
         assert.equal(item.msgid, 'Add order');
         assert.equal(item.msgstr, 'Order toevoegen');
+
+        item = po.items[2];
+        assert.equal(item.obsolete, true);
+        assert.equal(item.msgid, 'Commented item');
+        assert.equal(item.msgstr, 'not sure');
+
+        item = po.items[3];
+        assert.equal(item.obsolete, true);
+        assert.equal(item.msgid, 'Second commented item');
+        assert.equal(item.msgstr, 'also not sure');
     });
 
     describe('C-Strings', function () {

test/write.js

@@ -61,6 +61,22 @@ describe('Write', function () {
         assertHasLine(str, '#~ msgstr "Order toevoegen"');
     });
 
+    it('write obsolete items with comment', function () {
+        var input = fs.readFileSync(__dirname + '/fixtures/commented.po', 'utf8');
+        var po = PO.parse(input);
+        var str = po.toString();
+
+        //this is what msgcat tool of gettext does: don't print #~ for comments
+        assertHasLine(str, '# commented obsolete item');
+        assertHasLine(str, '#, fuzzy');
+
+        //items made obsolete by commenting every keyword with #~
+        assertHasLine(str, '#~ msgid "Commented item"');
+        assertHasLine(str, '#~ msgstr "not sure"');
+        assertHasLine(str, '#~ msgid "Second commented item"');
+        assertHasLine(str, '#~ msgstr "also not sure"');
+    });
+
     describe('C-Strings', function () {
         it('should escape "', function () {
             var item = new PO.Item();