fix: return non-dict objects loaded if the parser allows that at once

- anyconfig.backend.base.load_with_fn: return non-dict objects loaded
  such like bare arrays, empty dicts and lists if the parser allows that
  at once without trying to convert the loaded data to a mapping object.
- anyconfig.backend.base.load_*: pass allow_primitives keyword option.
- tests.backend.common.Test_10_dumps_and_loads: follow changes in
  anyconfig.backend.base.load_with_fn and compare results with
  predefined expected values in test_22_loads_empty_data.
- tests.backend.common.Test_20_dump_and_load: add a test case
  (test_34_dump_and_load__list) to dump and load list data
- tests.backend.{json,yaml}: follow changes in
  tests.backend.common.Test_10_dumps_and_loads

anyconfig/backend/base.py

@@ -567,12 +567,10 @@ def load_with_fn(load_fn, content_or_strm, container, allow_primitives=False,
     :return: container object holding data
     """
     ret = load_fn(content_or_strm, **options)
-    try:
-        return container() if ret is None else container(ret)
-    except (TypeError, ValueError):
-        if allow_primitives:
-            return ret  # Just return it.
-        raise  # Something goes wrong.
+    if anyconfig.utils.is_dict_like(ret):
+        return container() if (ret is None or not ret) else container(ret)
+
+    return ret if allow_primitives else container(ret)
 
 
 def dump_with_fn(dump_fn, data, stream, **options):
@@ -627,7 +625,8 @@ def load_from_string(self, content, container, **options):
         :return: container object holding the configuration data
         """
         return load_with_fn(self._load_from_string_fn, content, container,
-                            self.allow_primitives(), **options)
+                            allow_primitives=self.allow_primitives(),
+                            **options)
 
     def load_from_stream(self, stream, container, **options):
         """
@@ -640,7 +639,8 @@ def load_from_stream(self, stream, container, **options):
         :return: container object holding the configuration data
         """
         return load_with_fn(self._load_from_stream_fn, stream, container,
-                            self.allow_primitives(), **options)
+                            allow_primitives=self.allow_primitives(),
+                            **options)
 
     def dump_to_string(self, cnf, **kwargs):
         """

anyconfig/backend/yaml.py

@@ -187,24 +187,27 @@ def _yml_load(stream, container, **options):
     return ret
 
 
-def _yml_dump(cnf, stream, **options):
+def _yml_dump(data, stream, **options):
     """An wrapper of yaml.safe_dump and yaml.dump.
 
-    :param cnf: Mapping object to dump
+    :param data: Some data to dump
     :param stream: a file or file-like object to dump YAML data
     """
+    _is_dict = anyconfig.utils.is_dict_like(data)
+
     if options.get("ac_safe", False):
         options = {}
-    elif not options.get("Dumper", False):
+    elif not options.get("Dumper", False) and _is_dict:
         # TODO: Any other way to get its constructor?
-        cnf_type = type(cnf)
-        maybe_container = options.get("ac_dict", cnf_type)
+        maybe_container = options.get("ac_dict", type(data))
         options["Dumper"] = _customized_dumper(maybe_container)
 
-    # Type information and the order of items are lost on dump currently.
-    cnf = anyconfig.dicts.convert_to(cnf, ac_dict=dict)
-    options = _filter_from_options("ac_dict", options)
-    return _yml_fnc("dump", cnf, stream, **options)
+    if _is_dict:
+        # Type information and the order of items are lost on dump currently.
+        data = anyconfig.dicts.convert_to(data, ac_dict=dict)
+        options = _filter_from_options("ac_dict", options)
+
+    return _yml_fnc("dump", data, stream, **options)
 
 
 class Parser(anyconfig.backend.base.StreamParser):

tests/backend/common.py

@@ -72,7 +72,7 @@ class Test_10_dumps_and_loads(TestBase):
 
     load_options = {}  # Must be set to a dict in children classes.
     dump_options = {}  # Do.
-    empty_patterns = ['']  # Do.
+    empty_patterns = [('', {})]  # Do.
 
     def test_10_loads(self):
         if self.is_ready():
@@ -118,9 +118,9 @@ def test_20_loads_with_dict_option(self):
 
     def test_22_loads_empty_data(self):
         if self.is_ready():
-            for pat in self.empty_patterns:
+            for pat, exp in self.empty_patterns:
                 cnf = self.psr.loads(pat)
-                self.assertEqual(cnf, dict())
+                self.assertEqual(cnf, exp)
 
     def test_30_dumps(self):
         if self.is_ready():
@@ -158,6 +158,8 @@ def tearDown(self):
 
 class Test_20_dump_and_load(TestBaseWithIO):
 
+    list_data = [dict(a=1, b=2), dict(a=2, b=3)]
+
     def test_10_load(self):
         if self.is_ready():
             cnf = self.psr.load(self.ioi)
@@ -202,4 +204,11 @@ def test_32_dump_to_stream(self):
             self.assertTrue(cnf)
             self._assert_dicts_equal(cnf)
 
+    def test_34_dump_and_load__list(self):
+        if self.is_ready() and self.psr.allow_primitives():
+            self.psr.dump(self.list_data, self.ioi)
+            cnf = self.psr.load(self.ioi, ac_dict=MyDict)
+            self.assertTrue(cnf)
+            self.assertEqual(cnf, self.list_data)
+
 # vim:sw=4:ts=4:et:

tests/backend/json.py

@@ -37,7 +37,7 @@ class HasParserTrait(TBC.HasParserTrait):
 class Test_10(TBC.Test_10_dumps_and_loads, HasParserTrait):
 
     load_options = dump_options = dict(parse_int=None, indent=2)
-    empty_patterns = ['', '{}', '[]', 'null']
+    empty_patterns = [('', {}), ('{}', {}), ('[]', []), ('null', None)]
 
 
 class Test_20(TBC.Test_20_dump_and_load, HasParserTrait):

tests/backend/yaml.py

@@ -46,7 +46,8 @@ class Test_10(TBC.Test_10_dumps_and_loads, HasParserTrait):
 
     load_options = dict(ac_safe=True, Loader=TT.yaml.loader.Loader)
     dump_options = dict(ac_safe=True)
-    empty_patterns = ['', ' ', "#%s#%s" % (os.linesep, os.linesep)]
+    empty_patterns = [('', {}), (' ', {}), ('[]', []),
+                      ("#%s#%s" % (os.linesep, os.linesep), {})]
 
 
 class Test_20(TBC.Test_20_dump_and_load, HasParserTrait):