Add sample() method to ArrayType and DictType

Update ArrayType and DictType so they have sample()
methods for the sphinxext code to use when documenting
nested types.

wsme/tests/test_types.py

@@ -355,3 +355,15 @@ class TestTypes(unittest.TestCase):
     def test_array_eq(self):
         l = [types.ArrayType(str)]
         assert types.ArrayType(str) in l
+
+    def test_array_sample(self):
+        s = types.ArrayType(str).sample()
+        assert isinstance(s, list)
+        assert s
+        assert s[0] == ''
+
+    def test_dict_sample(self):
+        s = types.DictType(str, str).sample()
+        assert isinstance(s, dict)
+        assert s
+        assert s == {'': ''}

wsme/types.py

@@ -34,6 +34,9 @@ class ArrayType(object):
         return isinstance(other, ArrayType) \
             and self.item_type == other.item_type
 
+    def sample(self):
+        return [getattr(self.item_type, 'sample', self.item_type)()]
+
     @property
     def item_type(self):
         if isinstance(self._item_type, weakref.ref):
@@ -67,6 +70,11 @@ class DictType(object):
     def __hash__(self):
         return hash((self.key_type, self.value_type))
 
+    def sample(self):
+        key = getattr(self.key_type, 'sample', self.key_type)()
+        value = getattr(self.value_type, 'sample', self.value_type)()
+        return {key: value}
+
     @property
     def value_type(self):
         if isinstance(self._value_type, weakref.ref):