Add infrastructure for test-helper methods

.gitignore

@@ -58,3 +58,4 @@ venv.bak/
 !.vscode/tasks.json
 !.vscode/launch.json
 !.vscode/extensions.json
+/.idea

stripe/api_resources/abstract/__init__.py

@@ -26,6 +26,11 @@
 
 from stripe.api_resources.abstract.custom_method import custom_method
 
+from stripe.api_resources.abstract.test_helpers import (
+    test_helpers,
+    APIResourceTestHelpers,
+)
+
 from stripe.api_resources.abstract.nested_resource_class_methods import (
     nested_resource_class_methods,
 )

stripe/api_resources/abstract/test_helpers.py

@@ -0,0 +1,49 @@
+from __future__ import absolute_import, division, print_function
+
+from stripe import error, util, six
+from stripe.six.moves.urllib.parse import quote_plus
+
+
+class APIResourceTestHelpers:
+    def __init__(self, resource):
+        self.resource = resource
+
+    @classmethod
+    def class_url(cls):
+        if cls == APIResourceTestHelpers:
+            raise NotImplementedError(
+                "APIResourceTestHelpers is an abstract class.  You should perform "
+                "actions on its subclasses (e.g. Charge, Customer)"
+            )
+        # Namespaces are separated in object names with periods (.) and in URLs
+        # with forward slashes (/), so replace the former with the latter.
+        base = cls._resource_cls.OBJECT_NAME.replace(".", "/")
+        return "/v1/test_helpers/%ss" % (base,)
+
+    def instance_url(self):
+        id = self.resource.get("id")
+
+        if not isinstance(id, six.string_types):
+            raise error.InvalidRequestError(
+                "Could not determine which URL to request: %s instance "
+                "has invalid ID: %r, %s. ID should be of type `str` (or"
+                " `unicode`)" % (type(self).__name__, id, type(id)),
+                "id",
+            )
+
+        id = util.utf8(id)
+        base = self.class_url()
+        extn = quote_plus(id)
+        return "%s/%s" % (base, extn)
+
+
+def test_helpers(cls):
+    def test_helpers_getter(self):
+        return self.TestHelpers(self)
+
+    cls.TestHelpers._resource_cls = cls
+    cls.TestHelpers._static_request = cls._static_request
+    cls.TestHelpers._static_request_stream = cls._static_request_stream
+
+    cls.test_helpers = property(test_helpers_getter)
+    return cls

tests/api_resources/abstract/test_test_helpers_api_resource.py

@@ -0,0 +1,61 @@
+from __future__ import absolute_import, division, print_function
+
+import stripe
+from stripe import util
+from stripe.api_resources.abstract import APIResourceTestHelpers
+
+
+class TestTestHelperAPIResource(object):
+    @stripe.api_resources.abstract.test_helpers
+    class MyTestHelpersResource(stripe.api_resources.abstract.APIResource):
+        OBJECT_NAME = "myresource"
+
+        @stripe.api_resources.abstract.custom_method(
+            "do_stuff", http_verb="post", http_path="do_the_thing"
+        )
+        class TestHelpers(APIResourceTestHelpers):
+            def __init__(self, resource):
+                self.resource = resource
+
+            def do_stuff(self, idempotency_key=None, **params):
+                url = self.instance_url() + "/do_the_thing"
+                headers = util.populate_headers(idempotency_key)
+                self.resource.refresh_from(
+                    self.resource.request("post", url, params, headers)
+                )
+                return self.resource
+
+    def test_call_custom_method_class(self, request_mock):
+        request_mock.stub_request(
+            "post",
+            "/v1/test_helpers/myresources/mid/do_the_thing",
+            {"id": "mid", "thing_done": True},
+            rheaders={"request-id": "req_id"},
+        )
+
+        obj = self.MyTestHelpersResource.TestHelpers.do_stuff("mid", foo="bar")
+
+        request_mock.assert_requested(
+            "post",
+            "/v1/test_helpers/myresources/mid/do_the_thing",
+            {"foo": "bar"},
+        )
+        assert obj.thing_done is True
+
+    def test_call_custom_method_instance(self, request_mock):
+        request_mock.stub_request(
+            "post",
+            "/v1/test_helpers/myresources/mid/do_the_thing",
+            {"id": "mid", "thing_done": True},
+            rheaders={"request-id": "req_id"},
+        )
+
+        obj = self.MyTestHelpersResource.construct_from({"id": "mid"}, "mykey")
+        obj.test_helpers.do_stuff(foo="bar")
+
+        request_mock.assert_requested(
+            "post",
+            "/v1/test_helpers/myresources/mid/do_the_thing",
+            {"foo": "bar"},
+        )
+        assert obj.thing_done is True

tox.ini

@@ -39,7 +39,8 @@ deps =
     pytest-cov >= 2.8.1, < 2.11.0
     pytest-mock >= 2.0.0
     pytest-xdist >= 1.31.0
-commands = pytest --cov {posargs:-n auto}
+# ignore stripe directory as all tests are inside ./tests
+commands = pytest --cov {posargs:-n auto} --ignore stripe
 # compilation flags can be useful when prebuilt wheels cannot be used, e.g.
 # PyPy 2 needs to compile the `cryptography` module. On macOS this can be done
 # by passing the following flags: