Rework graph flow unit tests

This commit adds unit tests that check graph flow methods without
executing or flattening it. Now-redundant tests from other test
suites are deleted.

Change-Id: I8dafe0f9b295428831eddb3f9fd48f042d2f1ffc

4 files changed, 264 insertions, 233 deletions

diff --git a/taskflow/patterns/graph_flow.py b/taskflow/patterns/graph_flow.py
index a835e0b..decf356 100644
--- a/taskflow/patterns/graph_flow.py
+++ b/taskflow/patterns/graph_flow.py
@@ -41,16 +41,6 @@ class Flow(flow.Flow):
         super(Flow, self).__init__(name, retry)
         self._graph = nx.freeze(nx.DiGraph())
 
-    def _validate(self, graph=None):
-        if graph is None:
-            graph = self._graph
-        # Ensure that there is a valid topological ordering.
-        if not nx.is_directed_acyclic_graph(graph):
-            raise exc.DependencyFailure("No path through the items in the"
-                                        " graph produces an ordering that"
-                                        " will allow for correct dependency"
-                                        " resolution")
-
     def link(self, u, v):
         """Link existing node u as a runtime dependency of existing node v."""
         if not self._graph.has_node(u):
@@ -86,7 +76,11 @@ class Flow(flow.Flow):
         with a frozen version of the replacement graph (this maintains the
         invariant that the underlying graph is immutable).
         """
-        self._validate(replacement_graph)
+        if not nx.is_directed_acyclic_graph(replacement_graph):
+            raise exc.DependencyFailure("No path through the items in the"
+                                        " graph produces an ordering that"
+                                        " will allow for correct dependency"
+                                        " resolution")
         self._graph = nx.freeze(replacement_graph)
 
     def add(self, *items):
diff --git a/taskflow/tests/unit/patterns/test_graph_flow.py b/taskflow/tests/unit/patterns/test_graph_flow.py
new file mode 100644
index 0000000..2a95ad2
--- /dev/null
+++ b/taskflow/tests/unit/patterns/test_graph_flow.py
@@ -0,0 +1,259 @@
+# -*- coding: utf-8 -*-
+
+#    Copyright (C) 2014 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 exceptions as exc
+from taskflow.patterns import graph_flow as gf
+from taskflow import retry
+
+from taskflow import test
+from taskflow.tests import utils
+
+
+def _task(name, provides=None, requires=None):
+    return utils.ProvidesRequiresTask(name, provides, requires)
+
+
+class GraphFlowTest(test.TestCase):
+
+    def test_graph_flow_starts_as_empty(self):
+        f = gf.Flow('test')
+
+        self.assertEqual(len(f), 0)
+        self.assertEqual(list(f), [])
+        self.assertEqual(list(f.iter_links()), [])
+
+        self.assertEqual(f.requires, set())
+        self.assertEqual(f.provides, set())
+
+        expected = 'taskflow.patterns.graph_flow.Flow: test; 0'
+        self.assertEqual(str(f), expected)
+
+    def test_graph_flow_add_nothing(self):
+        f = gf.Flow('test')
+        result = f.add()
+        self.assertIs(f, result)
+        self.assertEqual(len(f), 0)
+
+    def test_graph_flow_one_task(self):
+        f = gf.Flow('test')
+        task = _task(name='task1', requires=['a', 'b'], provides=['c', 'd'])
+        result = f.add(task)
+
+        self.assertIs(f, result)
+
+        self.assertEqual(len(f), 1)
+        self.assertEqual(list(f), [task])
+        self.assertEqual(list(f.iter_links()), [])
+        self.assertEqual(f.requires, set(['a', 'b']))
+        self.assertEqual(f.provides, set(['c', 'd']))
+
+    def test_graph_flow_two_independent_tasks(self):
+        task1 = _task(name='task1')
+        task2 = _task(name='task2')
+        f = gf.Flow('test').add(task1, task2)
+
+        self.assertEqual(len(f), 2)
+        self.assertItemsEqual(f, [task1, task2])
+        self.assertEqual(list(f.iter_links()), [])
+
+    def test_graph_flow_two_dependent_tasks(self):
+        task1 = _task(name='task1', provides=['a'])
+        task2 = _task(name='task2', requires=['a'])
+        f = gf.Flow('test').add(task1, task2)
+
+        self.assertEqual(len(f), 2)
+        self.assertItemsEqual(f, [task1, task2])
+        self.assertEqual(list(f.iter_links()), [
+            (task1, task2, {'reasons': set(['a'])})
+        ])
+
+        self.assertEqual(f.requires, set())
+        self.assertEqual(f.provides, set(['a']))
+
+    def test_graph_flow_two_dependent_tasks_two_different_calls(self):
+        task1 = _task(name='task1', provides=['a'])
+        task2 = _task(name='task2', requires=['a'])
+        f = gf.Flow('test').add(task1).add(task2)
+
+        self.assertEqual(len(f), 2)
+        self.assertItemsEqual(f, [task1, task2])
+        self.assertEqual(list(f.iter_links()), [
+            (task1, task2, {'reasons': set(['a'])})
+        ])
+
+    def test_graph_flow_two_task_same_provide(self):
+        task1 = _task(name='task1', provides=['a', 'b'])
+        task2 = _task(name='task2', provides=['a', 'c'])
+        f = gf.Flow('test')
+        self.assertRaises(exc.DependencyFailure, f.add, task2, task1)
+
+    def test_graph_flow_with_retry(self):
+        ret = retry.AlwaysRevert(requires=['a'], provides=['b'])
+        f = gf.Flow('test', ret)
+        self.assertIs(f.retry, ret)
+        self.assertEqual(ret.name, 'test_retry')
+
+        self.assertEqual(f.requires, set(['a']))
+        self.assertEqual(f.provides, set(['b']))
+
+    def test_graph_flow_ordering(self):
+        task1 = _task('task1', provides=set(['a', 'b']))
+        task2 = _task('task2', provides=['c'], requires=['a', 'b'])
+        task3 = _task('task3', provides=[], requires=['c'])
+        f = gf.Flow('test').add(task1, task2, task3)
+
+        self.assertEqual(3, len(f))
+
+        self.assertItemsEqual(list(f.iter_links()), [
+            (task1, task2, {'reasons': set(['a', 'b'])}),
+            (task2, task3, {'reasons': set(['c'])})
+        ])
+
+    def test_graph_flow_links(self):
+        task1 = _task('task1')
+        task2 = _task('task2')
+        f = gf.Flow('test').add(task1, task2)
+        linked = f.link(task1, task2)
+        self.assertIs(linked, f)
+        self.assertItemsEqual(list(f.iter_links()), [
+            (task1, task2, {'manual': True})
+        ])
+
+    def test_graph_flow_links_and_dependencies(self):
+        task1 = _task('task1', provides=['a'])
+        task2 = _task('task2', requires=['a'])
+        f = gf.Flow('test').add(task1, task2)
+        linked = f.link(task1, task2)
+        self.assertIs(linked, f)
+        expected_meta = {
+            'manual': True,
+            'reasons': set(['a'])
+        }
+        self.assertItemsEqual(list(f.iter_links()), [
+            (task1, task2, expected_meta)
+        ])
+
+    def test_graph_flow_link_from_unknown_node(self):
+        task1 = _task('task1')
+        task2 = _task('task2')
+        f = gf.Flow('test').add(task2)
+        self.assertRaisesRegexp(ValueError, 'Item .* not found to link from',
+                                f.link, task1, task2)
+
+    def test_graph_flow_link_to_unknown_node(self):
+        task1 = _task('task1')
+        task2 = _task('task2')
+        f = gf.Flow('test').add(task1)
+        self.assertRaisesRegexp(ValueError, 'Item .* not found to link to',
+                                f.link, task1, task2)
+
+    def test_graph_flow_link_raises_on_cycle(self):
+        task1 = _task('task1', provides=['a'])
+        task2 = _task('task2', requires=['a'])
+        f = gf.Flow('test').add(task1, task2)
+        self.assertRaises(exc.DependencyFailure, f.link, task2, task1)
+
+    def test_graph_flow_link_raises_on_link_cycle(self):
+        task1 = _task('task1')
+        task2 = _task('task2')
+        f = gf.Flow('test').add(task1, task2)
+        f.link(task1, task2)
+        self.assertRaises(exc.DependencyFailure, f.link, task2, task1)
+
+    def test_graph_flow_dependency_cycle(self):
+        task1 = _task('task1', provides=['a'], requires=['c'])
+        task2 = _task('task2', provides=['b'], requires=['a'])
+        task3 = _task('task3', provides=['c'], requires=['b'])
+        f = gf.Flow('test').add(task1, task2)
+        self.assertRaises(exc.DependencyFailure, f.add, task3)
+
+
+class TargetedGraphFlowTest(test.TestCase):
+
+    def test_targeted_flow_restricts(self):
+        f = gf.TargetedFlow("test")
+        task1 = _task('task1', provides=['a'], requires=[])
+        task2 = _task('task2', provides=['b'], requires=['a'])
+        task3 = _task('task3', provides=[], requires=['b'])
+        task4 = _task('task4', provides=[], requires=['b'])
+        f.add(task1, task2, task3, task4)
+        f.set_target(task3)
+        self.assertEqual(len(f), 3)
+        self.assertItemsEqual(f, [task1, task2, task3])
+        self.assertNotIn('c', f.provides)
+
+    def test_targeted_flow_reset(self):
+        f = gf.TargetedFlow("test")
+        task1 = _task('task1', provides=['a'], requires=[])
+        task2 = _task('task2', provides=['b'], requires=['a'])
+        task3 = _task('task3', provides=[], requires=['b'])
+        task4 = _task('task4', provides=['c'], requires=['b'])
+        f.add(task1, task2, task3, task4)
+        f.set_target(task3)
+        f.reset_target()
+        self.assertEqual(len(f), 4)
+        self.assertItemsEqual(f, [task1, task2, task3, task4])
+        self.assertIn('c', f.provides)
+
+    def test_targeted_flow_bad_target(self):
+        f = gf.TargetedFlow("test")
+        task1 = _task('task1', provides=['a'], requires=[])
+        task2 = _task('task2', provides=['b'], requires=['a'])
+        f.add(task1)
+        self.assertRaisesRegexp(ValueError, '^Item .* not found',
+                                f.set_target, task2)
+
+    def test_targeted_flow_one_node(self):
+        f = gf.TargetedFlow("test")
+        task1 = _task('task1', provides=['a'], requires=[])
+        f.add(task1)
+        f.set_target(task1)
+        self.assertEqual(len(f), 1)
+        self.assertItemsEqual(f, [task1])
+
+    def test_recache_on_add(self):
+        f = gf.TargetedFlow("test")
+        task1 = _task('task1', provides=[], requires=['a'])
+        f.add(task1)
+        f.set_target(task1)
+        self.assertEqual(1, len(f))
+        task2 = _task('task2', provides=['a'], requires=[])
+        f.add(task2)
+        self.assertEqual(2, len(f))
+
+    def test_recache_on_add_no_deps(self):
+        f = gf.TargetedFlow("test")
+        task1 = _task('task1', provides=[], requires=[])
+        f.add(task1)
+        f.set_target(task1)
+        self.assertEqual(1, len(f))
+        task2 = _task('task2', provides=[], requires=[])
+        f.add(task2)
+        self.assertEqual(1, len(f))
+
+    def test_recache_on_link(self):
+        f = gf.TargetedFlow("test")
+        task1 = _task('task1', provides=[], requires=[])
+        task2 = _task('task2', provides=[], requires=[])
+        f.add(task1, task2)
+        f.set_target(task1)
+        self.assertEqual(1, len(f))
+
+        f.link(task2, task1)
+        self.assertEqual(2, len(f))
+        self.assertEqual(list(f.iter_links()), [
+            (task2, task1, {'manual': True})
+        ])
diff --git a/taskflow/tests/unit/test_flow_dependencies.py b/taskflow/tests/unit/test_flow_dependencies.py
index 8f5d680..3d02939 100644
--- a/taskflow/tests/unit/test_flow_dependencies.py
+++ b/taskflow/tests/unit/test_flow_dependencies.py
@@ -194,13 +194,6 @@ class FlowDependenciesTest(test.TestCase):
                           flow.add,
                           gf.Flow('gf').add(utils.TaskOneReturn(provides='x')))
 
-    def test_graph_flow_without_dependencies(self):
-        flow = gf.Flow('gf').add(
-            utils.TaskNoRequiresNoReturns('task1'),
-            utils.TaskNoRequiresNoReturns('task2'))
-        self.assertEqual(flow.requires, set())
-        self.assertEqual(flow.provides, set())
-
     def test_graph_flow_requires_values(self):
         flow = gf.Flow('gf').add(
             utils.TaskOneArg('task1'),
diff --git a/taskflow/tests/unit/test_graph_flow.py b/taskflow/tests/unit/test_graph_flow.py
deleted file mode 100644
index 4618c24..0000000
--- a/taskflow/tests/unit/test_graph_flow.py
+++ /dev/null
@@ -1,215 +0,0 @@
-# -*- coding: utf-8 -*-
-
-#    Copyright (C) 2012 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.
-
-import collections
-
-import taskflow.engines
-
-from taskflow.patterns import graph_flow as gw
-from taskflow.utils import flow_utils as fu
-from taskflow.utils import graph_utils as gu
-
-from taskflow import test
-from taskflow.tests import utils
-
-
-class GraphFlowTest(test.TestCase):
-    def _make_engine(self, flow):
-        return taskflow.engines.load(flow, store={})
-
-    def _capture_states(self):
-        # TODO(harlowja): move function to shared helper.
-        capture_where = collections.defaultdict(list)
-
-        def do_capture(state, details):
-            task_uuid = details.get('task_uuid')
-            if not task_uuid:
-                return
-            capture_where[task_uuid].append(state)
-
-        return (do_capture, capture_where)
-
-    def test_ordering(self):
-        wf = gw.Flow("the-test-action")
-        test_1 = utils.ProvidesRequiresTask('test-1',
-                                            requires=[],
-                                            provides=set(['a', 'b']))
-        test_2 = utils.ProvidesRequiresTask('test-2',
-                                            provides=['c'],
-                                            requires=['a', 'b'])
-        test_3 = utils.ProvidesRequiresTask('test-3',
-                                            provides=[],
-                                            requires=['c'])
-        wf.add(test_1, test_2, test_3)
-        self.assertEqual(3, len(wf))
-
-        edges = [(src, dst) for src, dst, _meta in wf.iter_links()]
-        self.assertIn((test_1, test_2), edges)
-        self.assertIn((test_2, test_3), edges)
-        self.assertEqual(2, len(edges))
-
-    def test_basic_edge_reasons(self):
-        wf = gw.Flow("the-test-action")
-        test_1 = utils.ProvidesRequiresTask('test-1',
-                                            requires=[],
-                                            provides=set(['a', 'b']))
-        test_2 = utils.ProvidesRequiresTask('test-2',
-                                            provides=['c'],
-                                            requires=['a', 'b'])
-        wf.add(test_1, test_2)
-        edges = list(wf.iter_links())
-        self.assertEqual(len(edges), 1)
-
-        from_task, to_task, edge_attrs = edges[0]
-        self.assertIs(from_task, test_1)
-        self.assertIs(to_task, test_2)
-
-        self.assertTrue(len(edge_attrs) > 0)
-        self.assertIn('reasons', edge_attrs)
-        self.assertEqual(set(['a', 'b']), edge_attrs['reasons'])
-
-    def test_linked_edge_reasons(self):
-        wf = gw.Flow("the-test-action")
-        test_1 = utils.ProvidesRequiresTask('test-1',
-                                            requires=[],
-                                            provides=[])
-        test_2 = utils.ProvidesRequiresTask('test-2',
-                                            provides=[],
-                                            requires=[])
-        wf.add(test_1, test_2)
-        self.assertEqual(len(list(wf.iter_links())), 0)
-
-        wf.link(test_1, test_2)
-        edges = list(wf.iter_links())
-        self.assertEqual(len(edges), 1)
-
-        from_task, to_task, edge_attrs = edges[0]
-        self.assertIs(from_task, test_1)
-        self.assertIs(to_task, test_2)
-
-        self.assertTrue(len(edge_attrs) > 0)
-        self.assertTrue(edge_attrs.get('manual'))
-
-    def test_flatten_attribute(self):
-        wf = gw.Flow("the-test-action")
-        test_1 = utils.ProvidesRequiresTask('test-1',
-                                            requires=[],
-                                            provides=[])
-        test_2 = utils.ProvidesRequiresTask('test-2',
-                                            provides=[],
-                                            requires=[])
-        wf.add(test_1, test_2)
-        wf.link(test_1, test_2)
-        g = fu.flatten(wf)
-        self.assertEqual(2, len(g))
-        edge_attrs = gu.get_edge_attrs(g, test_1, test_2)
-        self.assertTrue(edge_attrs.get('manual'))
-        self.assertTrue(edge_attrs.get('flatten'))
-
-
-class TargetedGraphFlowTest(test.TestCase):
-
-    def test_targeted_flow(self):
-        wf = gw.TargetedFlow("test")
-        test_1 = utils.ProvidesRequiresTask('test-1',
-                                            provides=['a'], requires=[])
-        test_2 = utils.ProvidesRequiresTask('test-2',
-                                            provides=['b'], requires=['a'])
-        test_3 = utils.ProvidesRequiresTask('test-3',
-                                            provides=[], requires=['b'])
-        test_4 = utils.ProvidesRequiresTask('test-4',
-                                            provides=[], requires=['b'])
-        wf.add(test_1, test_2, test_3, test_4)
-        wf.set_target(test_3)
-        g = fu.flatten(wf)
-        self.assertEqual(3, len(g))
-        self.assertFalse(g.has_node(test_4))
-        self.assertFalse('c' in wf.provides)
-
-    def test_targeted_flow_reset(self):
-        wf = gw.TargetedFlow("test")
-        test_1 = utils.ProvidesRequiresTask('test-1',
-                                            provides=['a'], requires=[])
-        test_2 = utils.ProvidesRequiresTask('test-2',
-                                            provides=['b'], requires=['a'])
-        test_3 = utils.ProvidesRequiresTask('test-3',
-                                            provides=[], requires=['b'])
-        test_4 = utils.ProvidesRequiresTask('test-4',
-                                            provides=['c'], requires=['b'])
-        wf.add(test_1, test_2, test_3, test_4)
-        wf.set_target(test_3)
-        wf.reset_target()
-        g = fu.flatten(wf)
-        self.assertEqual(4, len(g))
-        self.assertTrue(g.has_node(test_4))
-
-    def test_targeted_flow_bad_target(self):
-        wf = gw.TargetedFlow("test")
-        test_1 = utils.ProvidesRequiresTask('test-1',
-                                            provides=['a'], requires=[])
-        test_2 = utils.ProvidesRequiresTask('test-2',
-                                            provides=['b'], requires=['a'])
-        wf.add(test_1)
-        self.assertRaisesRegexp(ValueError, '^Item .* not found',
-                                wf.set_target, test_2)
-
-    def test_targeted_flow_one_node(self):
-        wf = gw.TargetedFlow("test")
-        test_1 = utils.ProvidesRequiresTask('test-1',
-                                            provides=['a'], requires=[])
-        wf.add(test_1)
-        wf.set_target(test_1)
-        g = fu.flatten(wf)
-        self.assertEqual(1, len(g))
-        self.assertTrue(g.has_node(test_1))
-
-    def test_recache_on_add(self):
-        wf = gw.TargetedFlow("test")
-        test_1 = utils.ProvidesRequiresTask('test-1',
-                                            provides=[], requires=['a'])
-        wf.add(test_1)
-        wf.set_target(test_1)
-        self.assertEqual(1, len(wf))
-        test_2 = utils.ProvidesRequiresTask('test-2',
-                                            provides=['a'], requires=[])
-        wf.add(test_2)
-        self.assertEqual(2, len(wf))
-
-    def test_recache_on_add_no_deps(self):
-        wf = gw.TargetedFlow("test")
-        test_1 = utils.ProvidesRequiresTask('test-1',
-                                            provides=[], requires=[])
-        wf.add(test_1)
-        wf.set_target(test_1)
-        self.assertEqual(1, len(wf))
-        test_2 = utils.ProvidesRequiresTask('test-2',
-                                            provides=[], requires=[])
-        wf.add(test_2)
-        self.assertEqual(1, len(wf))
-
-    def test_recache_on_link(self):
-        wf = gw.TargetedFlow("test")
-        test_1 = utils.ProvidesRequiresTask('test-1',
-                                            provides=[], requires=[])
-        test_2 = utils.ProvidesRequiresTask('test-2',
-                                            provides=[], requires=[])
-        wf.add(test_1, test_2)
-        wf.set_target(test_1)
-        self.assertEqual(1, len(wf))
-        wf.link(test_2, test_1)
-        self.assertEqual(2, len(wf))
-        edges = [(src, dst) for src, dst, _meta in wf.iter_links()]
-        self.assertEqual([(test_2, test_1)], edges)