Merge pull request #1 from open-contracting/dev

.gitignore

@@ -1,3 +1,4 @@
 /.cache
 /.coverage
+/dist
 /*.egg-info

CHANGELOG.md

@@ -0,0 +1,12 @@
+# Changelog
+
+## 0.0.2 (2018-06-12)
+
+* Make `ExtensionRegistry` iterable.
+* Remove `all()` method from `ExtensionRegistry`.
+* Add `get(**kwargs)` method to `ExtensionRegistry`.
+* Add package-specific exceptions.
+
+## 0.0.1 (2018-06-11)
+
+First release.

ocdsextensionregistry/__init__.py

@@ -6,6 +6,18 @@
 import requests
 
 
+class OCDSExtensionRegistryError(Exception):
+    """Base class for exceptions from within this package"""
+
+
+class DoesNotExist(OCDSExtensionRegistryError):
+    """Raised if an object wasn't found for the given parameters"""
+
+
+class MissingExtensionMetadata(OCDSExtensionRegistryError):
+    """Raised if a method call requires extensions metadata, with which the extension registry was not initialized"""
+
+
 class ExtensionRegistry:
     def __init__(self, extension_versions_data, extensions_data=None):
         """
@@ -37,16 +49,22 @@ def filter(self, **kwargs):
         try:
             return list(filter(lambda ver: all(getattr(ver, k) == v for k, v in kwargs.items()), self.versions))
         except AttributeError as e:
-            if "'category'" in str(e.args) or "'core'" in str(e.args):
-                raise Exception('You must initialize ExtensionRegistry with two arguments.') from e
-            else:
-                raise
+            self._handle_attribute_error(e)
 
-    def all(self):
+    def get(self, **kwargs):
         """
-        Returns all the extension versions in the registry.
+        Returns the first extension version in the registry that matches the keyword arguments.
         """
-        return self.versions
+        try:
+            return next(ver for ver in self.versions if all(getattr(ver, k) == v for k, v in kwargs.items()))
+        except StopIteration:
+            raise DoesNotExist('Extension version matching {} does not exist.'.format(repr(kwargs)))
+        except AttributeError as e:
+            self._handle_attribute_error(e)
+
+    def __iter__(self):
+        for version in self.versions:
+            yield version
 
     def _resolve(self, data_or_url):
         parsed = urlparse(data_or_url)
@@ -55,6 +73,12 @@ def _resolve(self, data_or_url):
         else:
             return data_or_url
 
+    def _handle_attribute_error(self, e):
+        if "'category'" in str(e.args) or "'core'" in str(e.args):
+            raise MissingExtensionMetadata('ExtensionRegistry must be initialized with extensions data.') from e
+        else:
+            raise
+
 
 class Extension:
     def __init__(self, data):

setup.py

@@ -5,7 +5,7 @@
 
 setup(
     name='ocdsextensionregistry',
-    version='0.0.0',
+    version='0.0.2',
     author='James McKinney',
     author_email='james@slashpoundbang.com',
     url='https://github.com/open-contracting/extension_registry.py',

tests/test_extension_registry.py

@@ -1,6 +1,6 @@
 import pytest
 
-from ocdsextensionregistry import ExtensionRegistry
+from ocdsextensionregistry import ExtensionRegistry, DoesNotExist, MissingExtensionMetadata
 
 extensions_url = 'https://raw.githubusercontent.com/open-contracting/extension_registry/master/extensions.csv'
 extension_versions_url = 'https://raw.githubusercontent.com/open-contracting/extension_registry/master/extension_versions.csv'  # noqa
@@ -34,6 +34,7 @@ def test_init_with_url():
     obj = ExtensionRegistry(extension_versions_url, extensions_url)
 
     assert len(obj.versions) > 50
+    # Skip testing data, as the data changes over time.
 
 
 def test_init_with_data():
@@ -49,6 +50,7 @@ def test_init_with_data():
         'category': 'ppp',
         'core': False,
     }
+    # Assume intermediate data is correctly parsed.
     assert obj.versions[-1].__dict__ == {
         'id': 'lots',
         'date': '2018-01-30',
@@ -71,6 +73,7 @@ def test_init_with_versions_only():
         'base_url': 'https://raw.githubusercontent.com/open-contracting/ocds_charges_extension/master/',
         'download_url': 'https://github.com/open-contracting/ocds_charges_extension/archive/master.zip',
     }
+    # Assume intermediate data is correctly parsed.
     assert obj.versions[-1].__dict__ == {
         'id': 'lots',
         'date': '2018-01-30',
@@ -85,20 +88,66 @@ def test_filter():
     result = obj.filter(core=True, version='v1.1.3', category='tender')
 
     assert len(result) == 2
-    assert result[0].id == 'enquiries'
-    assert result[1].id == 'lots'
+    assert result[0].__dict__ == {
+        'id': 'enquiries',
+        'date': '2018-02-01',
+        'version': 'v1.1.3',
+        'base_url': 'https://raw.githubusercontent.com/open-contracting/ocds_enquiry_extension/v1.1.3/',
+        'download_url': 'https://api.github.com/repos/open-contracting/ocds_enquiry_extension/zipball/v1.1.3',
+        'category': 'tender',
+        'core': True,
+    }
+    assert result[1].__dict__ == {
+        'id': 'lots',
+        'date': '2018-01-30',
+        'version': 'v1.1.3',
+        'base_url': 'https://raw.githubusercontent.com/open-contracting/ocds_lots_extension/v1.1.3/',
+        'download_url': 'https://api.github.com/repos/open-contracting/ocds_lots_extension/zipball/v1.1.3',
+        'category': 'tender',
+        'core': True,
+    }
 
 
 def test_filter_without_extensions():
     obj = ExtensionRegistry(extension_versions_data)
-    with pytest.raises(Exception) as excinfo:
+    with pytest.raises(MissingExtensionMetadata) as excinfo:
         obj.filter(category='tender')
 
-    assert str(excinfo.value) == 'You must initialize ExtensionRegistry with two arguments.'
+    assert str(excinfo.value) == 'ExtensionRegistry must be initialized with extensions data.'
+
+
+def test_get():
+    obj = ExtensionRegistry(extension_versions_data)
+    result = obj.get(id='lots', version='v1.1.3')
+
+    assert result.__dict__ == {
+        'id': 'lots',
+        'date': '2018-01-30',
+        'version': 'v1.1.3',
+        'base_url': 'https://raw.githubusercontent.com/open-contracting/ocds_lots_extension/v1.1.3/',
+        'download_url': 'https://api.github.com/repos/open-contracting/ocds_lots_extension/zipball/v1.1.3',
+    }
+
+
+def test_get_no_match():
+    obj = ExtensionRegistry(extension_versions_data)
+    with pytest.raises(DoesNotExist) as excinfo:
+        obj.get(id='nonexistent')
+
+    assert str(excinfo.value) == "Extension version matching {'id': 'nonexistent'} does not exist."
+
+
+def test_get_without_extensions():
+    obj = ExtensionRegistry(extension_versions_data)
+    with pytest.raises(MissingExtensionMetadata) as excinfo:
+        obj.get(category='tender')
+
+    assert str(excinfo.value) == 'ExtensionRegistry must be initialized with extensions data.'
 
 
-def test_all():
+def test_iter():
     obj = ExtensionRegistry(extension_versions_data)
-    result = obj.all()
+    for i, version in enumerate(obj, 1):
+        pass
 
-    assert len(result) == 14
+    assert i == 14