Support fromYAML classmethod for all Munch subclasses (fixes #34)

CHANGELOG.md

@@ -4,6 +4,8 @@ Changelog
 Next Version
 ------------
 
+* Support ``fromYAML`` classmethod for all Munch subclasses (PR [#52](https://github.com/Infinidat/munch/pull/52) fixes [#34](https://github.com/Infinidat/munch/issues/34)
+
 2.4.0 (2019-10-29)
 ------------------
 

munch/__init__.py

@@ -615,12 +615,13 @@ def toYAML(self, **options):
         else:
             return yaml.dump(self, **opts)
 
-    def fromYAML(*args, **kwargs):
-        kwargs.setdefault('Loader', yaml.FullLoader)
-        return munchify(yaml.load(*args, **kwargs))
+    def fromYAML(cls, stream, *args, **kwargs):
+        factory = lambda d: cls(*(args + (d,)), **kwargs)
+        loader_class = kwargs.pop('Loader', yaml.FullLoader)
+        return munchify(yaml.load(stream, Loader=loader_class), factory=factory)
 
     Munch.toYAML = toYAML
-    Munch.fromYAML = staticmethod(fromYAML)
+    Munch.fromYAML = classmethod(fromYAML)
 
 except ImportError:
     pass

tests/test_yaml.py

@@ -1,5 +1,5 @@
 import pytest
-from munch import Munch
+from munch import Munch, DefaultMunch
 
 
 def test_from_yaml(yaml):
@@ -39,7 +39,22 @@ def test_toYAML(yaml):
 
 @pytest.mark.usefixtures('yaml')
 def test_fromYAML():
+    # pylint: disable=unidiomatic-typecheck
     yaml_str = 'foo:\n    bar:\n    - 1\n    - 2\n    hello: world\n'
     obj = Munch.fromYAML(yaml_str)
+    assert type(obj) == Munch
     assert obj == Munch(foo=Munch(bar=[1, 2], hello='world'))
     assert obj.toYAML() == yaml_str
+
+
+@pytest.mark.usefixtures('yaml')
+def test_fromYAML_default_munch():
+    # pylint: disable=unidiomatic-typecheck
+    yaml_str = 'foo:\n    bar:\n    - 1\n    - 2\n    hello: world\n'
+    default_value = object()
+    obj = DefaultMunch.fromYAML(yaml_str, default_value)
+    assert type(obj) == DefaultMunch
+    assert obj == DefaultMunch(foo=Munch(bar=[1, 2], hello='world'))
+    assert obj['not_exist'] is default_value
+    assert obj.not_exist is default_value
+    assert obj.toYAML() == yaml_str