From b68d504c9f99e180f0d630c5c101bd6136d23933 Mon Sep 17 00:00:00 2001
From: "Ivan A. Melnikov" <imelnikov@griddynamics.com>
Date: Tue, 27 Aug 2013 16:52:56 +0400
Subject: [PATCH] Add features to task.Task

Old Task class renamed to BaseTask, and new Task class deriving from it
added in place of it. This new class adds following features:
- if no name is passed to task, name is autogenerated from task type
- all __call__ argument names (except 'context') are added to task
  requirements.

Change-Id: Ied69857932088b6e25d4817d2a8afeddccad36d8
---
 taskflow/task.py                 | 29 ++++++++++++++++++--
 taskflow/tests/unit/test_task.py | 46 ++++++++++++++++++++++++++++++++
 2 files changed, 73 insertions(+), 2 deletions(-)
 create mode 100644 taskflow/tests/unit/test_task.py

diff --git a/taskflow/task.py b/taskflow/task.py
index 2a27b97af..90e9c08d7 100644
--- a/taskflow/task.py
+++ b/taskflow/task.py
@@ -3,6 +3,7 @@
 # vim: tabstop=4 shiftwidth=4 softtabstop=4
 
 #    Copyright (C) 2013 Rackspace Hosting Inc. All Rights Reserved.
+#    Copyright (C) 2013 Yahoo! Inc. All Rights Reserved.
 #
 #    Licensed under the Apache License, Version 2.0 (the "License"); you may
 #    not use this file except in compliance with the License. You may obtain
@@ -21,7 +22,7 @@ import abc
 from taskflow import utils
 
 
-class Task(object):
+class BaseTask(object):
     """An abstraction that defines a potential piece of work that can be
     applied and can be reverted to undo the work as a single unit.
     """
@@ -68,7 +69,31 @@ class Task(object):
         """
 
 
-class FunctorTask(Task):
+class Task(BaseTask):
+    """Base class for user-defined tasks
+
+    Adds following features to Task:
+        - auto-generates name from type of self
+        - adds all __call__ argument names to task requiremets
+    """
+
+    def __init__(self, name=None, requires_from_args=True):
+        """Initialize task instance
+
+        :param name: task name, if None (the default) name will
+            be autogenerated
+        :param requires_from_args: if True (the default) __call__
+            arguments names will be added to task requirements
+        """
+        if name is None:
+            name = utils.get_callable_name(self)
+        super(Task, self).__init__(name)
+        if requires_from_args:
+            f_args = utils.get_required_callable_args(self)
+            self.requires.update(a for a in f_args if a != 'context')
+
+
+class FunctorTask(BaseTask):
     """Adaptor to make task from a callable
 
     Take any callable and make a task from it.
diff --git a/taskflow/tests/unit/test_task.py b/taskflow/tests/unit/test_task.py
new file mode 100644
index 000000000..05e1085ac
--- /dev/null
+++ b/taskflow/tests/unit/test_task.py
@@ -0,0 +1,46 @@
+# -*- coding: utf-8 -*-
+
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+#    Copyright (C) 2013 Yahoo! Inc. All Rights Reserved.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+
+from taskflow import task
+from taskflow import test
+
+
+class MyTask(task.Task):
+    def __call__(self, context, spam, eggs):
+        pass
+
+
+class TaskTestCase(test.TestCase):
+
+    def test_passed_name(self):
+        my_task = MyTask(name='my name')
+        self.assertEquals(my_task.name, 'my name')
+
+    def test_generated_name(self):
+        my_task = MyTask()
+        self.assertEquals(my_task.name,
+                          '%s.%s' % (__name__, 'MyTask'))
+
+    def test_requirements_added(self):
+        my_task = MyTask()
+        self.assertEquals(my_task.requires, set(['spam', 'eggs']))
+
+    def test_requirements_can_be_ignored(self):
+        my_task = MyTask(requires_from_args=False)
+        self.assertEquals(my_task.requires, set())