Raise KeyError for missing INI sections

decouple.py

@@ -11,10 +11,10 @@
 
 
 if PYVERSION >= (3, 0, 0):
-    from configparser import ConfigParser, NoOptionError
+    from configparser import ConfigParser, NoOptionError, NoSectionError
     text_type = str
 else:
-    from ConfigParser import SafeConfigParser as ConfigParser, NoOptionError
+    from ConfigParser import SafeConfigParser as ConfigParser, NoOptionError, NoSectionError
     text_type = unicode
 
 if PYVERSION >= (3, 2, 0):
@@ -136,7 +136,7 @@ def __contains__(self, key):
     def __getitem__(self, key):
         try:
             return self.parser.get(self.SECTION, key)
-        except NoOptionError:
+        except (NoOptionError, NoSectionError):
             raise KeyError(key)
 
 

tests/test_ini_missing_section.py

@@ -0,0 +1,47 @@
+# coding: utf-8
+from io import StringIO
+
+import pytest
+from mock import patch
+
+from decouple import RepositoryIni
+
+try:
+    from configparser import InterpolationMissingOptionError
+except ImportError:
+    from ConfigParser import InterpolationMissingOptionError
+
+
+@pytest.mark.parametrize('contents', ['', '[other]\nkey=value\n'])
+def test_ini_without_settings_raises_keyerror(contents):
+    with patch('decouple.open', return_value=StringIO(contents), create=True):
+        repository = RepositoryIni('settings.ini')
+    assert 'missing' not in repository
+    with pytest.raises(KeyError) as error:
+        repository['missing']
+    assert error.value.args == ('missing',)
+
+
+@pytest.mark.parametrize('contents', ['', '[other]\nkey=value\n'])
+def test_ini_without_settings_allows_repository_fallback(contents):
+    with patch('decouple.open', return_value=StringIO(contents), create=True):
+        repository = RepositoryIni('settings.ini')
+
+    def lookup(key):
+        for source in (repository, {'fallback': 'value'}):
+            try:
+                return source[key]
+            except KeyError:
+                pass
+        raise KeyError(key)
+
+    assert lookup('fallback') == 'value'
+
+
+def test_ini_preserves_interpolation_errors():
+    contents = '[settings]\nkey=%(missing)s\n'
+    with patch('decouple.open', return_value=StringIO(contents), create=True):
+        repository = RepositoryIni('settings.ini')
+    assert 'key' in repository
+    with pytest.raises(InterpolationMissingOptionError):
+        repository['key']