Tests for dumping and loading to file by name

serialize/all.py

@@ -206,7 +206,8 @@ def traverse_and_decode(obj, decode_func=None, trav_dict=None):
 def register_format(fmt, dumpser=None, loadser=None, dumper=None, loader=None, extension=MISSING):
     """Register an available serialization format.
 
-    `fmt` is a unique string identifying the format, such as `json`.
+    `fmt` is a unique string identifying the format, such as `json`. Use a colon (`:`) to
+    separate between subformats.
 
     `dumpser` and `dumper` should be callables with the same purpose and arguments
     that `json.dumps` and `json.dump`. If one of those is missing, it will be
@@ -217,9 +218,8 @@ def register_format(fmt, dumpser=None, loadser=None, dumper=None, loader=None, e
     generated automatically from the other.
 
     `extension` is the file extension used to guess the desired serialization format when loading
-    from or dumping to a file. If not given, `fmt` will be used.
-    If `None`, the format will not be associated with any extension (use for serialization formats
-    with multiple subformats in which you want to select a default).
+    from or dumping to a file. If not given, the part before the colon of `fmt` will be used.
+    If `None`, the format will not be associated with any extension.
     """
 
     # For simplicity. We do not allow to overwrite format.
@@ -259,11 +259,11 @@ def raiser(*args, **kwargs):
         loader = loadser = raiser
 
     if extension is MISSING:
-        extension = fmt
+        extension = fmt.split(':', 1)[0]
 
     FORMATS[fmt] = Format(extension, dumper, dumpser, loader, loadser)
 
-    if extension:
+    if extension and extension not in FORMAT_BY_EXTENSION:
         FORMAT_BY_EXTENSION[extension.lower()] = fmt
 
 
@@ -277,13 +277,12 @@ def register_unavailable(fmt, msg='', pkg='', extension=MISSING):
     if pkg:
         msg = 'This serialization format requires the %s package.' % pkg
 
-
     if extension is MISSING:
-        extension = fmt
+        extension = fmt.split(':', 1)[0]
 
     UNAVAILABLE_FORMATS[fmt] = UnavailableFormat(extension, msg)
 
-    if extension:
+    if extension and extension not in FORMAT_BY_EXTENSION:
         FORMAT_BY_EXTENSION[extension.lower()] = fmt
 
 
@@ -329,7 +328,7 @@ def load(filename_or_file, fmt=None):
         if fmt is None:
             _, ext = splitext(filename_or_file)
             fmt = _get_format_from_ext(ext.strip('.'))
-        with open(filename_or_file, 'wb') as fp:
+        with open(filename_or_file, 'rb') as fp:
             return load(fp, fmt)
 
     return _get_format(fmt).load(filename_or_file)

serialize/json.py

@@ -44,4 +44,4 @@ def loads(content):
 # The first (default) is compact, the second is pretty.
 
 all.register_format('json', dumps, loads)
-all.register_format('json:pretty', dumps_pretty, loads, extension=None)
+all.register_format('json:pretty', dumps_pretty, loads)

serialize/testsuite/test_basic.py

@@ -4,7 +4,8 @@
 from unittest import TestCase, skipIf
 
 from serialize import register_class, loads, dumps, load, dump
-from serialize.all import (FORMATS, UNAVAILABLE_FORMATS, _get_format_from_ext,
+from serialize.all import (FORMATS, UNAVAILABLE_FORMATS,
+                           _get_format_from_ext, _get_format,
                            register_format)
 
 
@@ -102,7 +103,25 @@ def _test_round_trip(self, obj):
         # dump / load
         self.assertEqual(obj, load(buf, self.FMT))
 
-
+    def test_file_by_name(self):
+        fh = _get_format(self.FMT)
+        obj = dict(answer=42)
+
+        filename1 = 'tmp.' + fh.extension
+        dump(obj, filename1)
+        try:
+            obj1 = load(filename1)
+            self.assertEqual(obj, obj1)
+        finally:
+            os.remove(filename1)
+
+        filename2 = 'tmp.' + fh.extension + '.bla'
+        dump(obj, filename2, fmt=self.FMT)
+        try:
+            obj2 = load(filename2, fmt=self.FMT)
+            self.assertEqual(obj, obj2)
+        finally:
+            os.remove(filename2)
 
     def test_format_from_ext(self):
         if ':' in self.FMT: