Don't dump additional empty line at the end

Fixes TypesettingTools/Myaamori-Aegisub-Scripts#22.

Author: FichteFoll

ass/document.py

@@ -147,6 +147,11 @@ def dump_file(self, f):
             warnings.warn("It is recommended to write UTF-8 with BOM"
                           " using the '%s' encoding" % self.PREFERRED_ENCODING.name)
 
+        first = True
         for section in self.sections.values():
-            f.write("\n".join(section.dump()))
-            f.write("\n\n")
+            if not first:
+                f.write("\n")
+            for line in section.dump():
+                f.write(line)
+                f.write("\n")
+            first = False

tests/test_ass.py

@@ -23,7 +23,7 @@ def test_parse_dump(self):
         out = StringIO()
         doc.dump_file(out)
 
-        assert out.getvalue().strip() == contents.strip()
+        assert out.getvalue() == contents
 
     def test_parse_encoding(self):
         with self.test_ass.open("r", encoding='utf_8') as f: