Add ResourceList to fix API list access (#40)

* Explicitly disallow unsupported comparisons between API models
* Added tests for ResourceLists, and comparison between models

onecodex/models/__init__.py

@@ -19,6 +19,89 @@
 DEFAULT_PAGE_SIZE = 200
 
 
+class ResourceList:
+    """
+    In OneCodexBase, when attributes are lists, actions performed on the returned lists are not
+    passed through to the underlying resource list. This class passes those actions through, and
+    will generally act like a list.
+    """
+
+    def _update(self):
+        self._res_list = [self.oc_model(x) for x in self._resource]
+
+    def __init__(self, _resource, oc_model):
+        # turn potion Resource objects into OneCodex objects
+        self._resource = _resource
+        self.oc_model = oc_model
+        self._update()
+
+    def __lt__(self, other):
+        raise NotImplementedError
+
+    def __le__(self, other):
+        raise NotImplementedError
+
+    def __gt__(self, other):
+        raise NotImplementedError
+
+    def __ge__(self, other):
+        raise NotImplementedError
+
+    def __eq__(self, other):
+        # two ResourceLists are equal if they refer to the same underlying Resource
+        return id(self._resource) == id(other._resource)
+
+    def __repr__(self):
+        self._update()
+        return self._res_list.__repr__()
+
+    def __len__(self):
+        self._update()
+        return len(self._res_list)
+
+    def __getitem__(self, x):
+        self._update()
+        return self._res_list[x]
+
+    def __setitem__(self, k, v):
+        if isinstance(v, self.oc_model) and \
+           isinstance(v._resource, Resource):
+            self._resource[k] = v._resource
+        else:
+            raise
+
+    def __delitem__(self, x):
+        del self._resource[x]
+
+    def __iter__(self):
+        self._update()
+        return self._res_list.__iter__()
+
+    def __reversed__(self):
+        self._update()
+        return reversed(self._res_list)
+
+    def append(self, x):
+        if isinstance(x, self.oc_model) and \
+           isinstance(x._resource, Resource):
+            self._resource.append(x._resource)
+        else:
+            raise
+
+    def extend(self, iterable):
+        for x in iterable:
+            self.append(x)
+
+    def pop(self):
+        self._update()
+        self._resource.pop()
+        return self._res_list.pop()
+
+    def clear(self):
+        self._resource.clear()
+        self._res_list.clear()
+
+
 class OneCodexBase(object):
     """
     A parent object for all the One Codex objects that wraps the Potion-Client API and makes
@@ -40,6 +123,18 @@ def __init__(self, _resource=None, **kwargs):
                     kwargs[key] = val._resource
             self._resource = self.__class__._resource(**kwargs)
 
+    def __lt__(self, other):
+        raise NotImplementedError
+
+    def __le__(self, other):
+        raise NotImplementedError
+
+    def __gt__(self, other):
+        raise NotImplementedError
+
+    def __ge__(self, other):
+        raise NotImplementedError
+
     def __repr__(self):
         return '<{} {}>'.format(self.__class__.__name__, self.id)
 
@@ -76,7 +171,7 @@ def __getattr__(self, key):
                 elif isinstance(value, list) and len(value) > 0 and isinstance(value[0], Resource):
                     # convert lists of potion resources into wrapped ones
                     resource_path = value[0]._uri.rsplit('/', 1)[0]
-                    return [_model_lookup[resource_path](_resource=o) for o in value]
+                    return ResourceList(value, _model_lookup[resource_path])
                 else:
                     if key == 'id':
                         # undo the bad coercion from potion_client/resource.py#L111

tests/test_api_models.py

@@ -39,6 +39,70 @@ def test_sample_get(ocx, api_data):
     assert 'isolate' in [t.name for t in tags]
 
 
+def test_resourcelist(ocx, api_data):
+    sample = ocx.Samples.get('761bc54b97f64980')
+    tags1 = onecodex.models.ResourceList(sample.tags._resource,
+                                         onecodex.models.misc.Tags)
+    tags2 = onecodex.models.ResourceList(sample.tags._resource,
+                                         onecodex.models.misc.Tags)
+
+    assert isinstance(sample.tags, onecodex.models.ResourceList)
+
+    # test manipulation of tags lists
+    tag_to_pop = sample.tags[-1]
+    popped_tag = sample.tags.pop()
+    assert id(tag_to_pop._resource) == id(popped_tag._resource)
+
+    # we can set tags list in-place
+    sample.tags[0] = popped_tag
+    assert id(sample.tags[0]._resource) == id(popped_tag._resource)
+
+    # changes in one instance of a ResourceList affect other instances
+    assert id(tags1) != id(tags2) != id(sample.tags)
+    assert id(tags1._resource) == id(tags2._resource) == id(sample.tags._resource)
+
+    assert len(tags1) == len(tags2) == len(sample.tags)
+
+    for i in range(len(tags1)):
+        assert tags1[i] == tags2[i] == sample.tags[i]
+
+
+def test_comparisons(ocx, api_data):
+    sample1 = ocx.Samples.get('761bc54b97f64980')
+    sample2 = ocx.Samples.get('761bc54b97f64980')
+
+    # should be different objects
+    assert id(sample1) != id(sample2)
+
+    # but they should reference the same Resource
+    assert id(sample1._resource) == id(sample2._resource)
+
+    # and so they should be equal
+    assert sample1 == sample2
+
+    # but any non-equivalence comparisons should throw errors
+    with pytest.raises(NotImplementedError):
+        sample1 > sample2
+    with pytest.raises(NotImplementedError):
+        sample1 >= sample2
+    with pytest.raises(NotImplementedError):
+        sample1 < sample2
+    with pytest.raises(NotImplementedError):
+        sample1 <= sample2
+
+    # and this should be true of ResourceLists too
+    assert sample1.tags == sample2.tags
+
+    with pytest.raises(NotImplementedError):
+        sample1.tags > sample2.tags
+    with pytest.raises(NotImplementedError):
+        sample1.tags >= sample2.tags
+    with pytest.raises(NotImplementedError):
+        sample1.tags < sample2.tags
+    with pytest.raises(NotImplementedError):
+        sample1.tags <= sample2.tags
+
+
 def test_dir_method(ocx, api_data):
     sample = ocx.Samples.get('761bc54b97f64980')