Check examples when running tests

Add testcase that executes all examples from taskflow/examples
directory. For examples with somewhat deterministic output the output
is also checked.

This commit also fixes couple of examples broken by recent decorators
refactoring.

Change-Id: I3e65eabde43e1dd26b442d8f7dd3f062bf80703d

taskflow/examples/fake_boot_vm.py

@@ -3,7 +3,6 @@ import os
 import random
 import sys
 import time
-import traceback
 import uuid
 
 logging.basicConfig(level=logging.ERROR)
@@ -173,12 +172,12 @@ print '-' * 7
 try:
     flo.run(context)
 except Exception as e:
-    traceback.print_exc()
+    print 'Flow failed: %r' % e
 
 print '-- Flow state %s' % (flo.state)
 
 print '-' * 11
 print 'All results'
 print '-' * 11
-for (tid, v) in flo.results.items():
+for (tid, v) in sorted(flo.results.items()):
     print '%s => %s' % (tid, v)

taskflow/examples/reverting_linear.out.txt

@@ -0,0 +1,7 @@
+Calling jim.
+Context = {'joe_number': 444, 'jim_number': 555}
+Calling joe.
+Context = {'joe_number': 444, 'jim_number': 555}
+Calling 444 and apologizing.
+Calling 555 and apologizing.
+Flow failed: IOError('Suzzie not home right now.',)

taskflow/examples/reverting_linear.py

@@ -30,6 +30,7 @@ def call_joe(context):
     return context['joe_number']
 
 
+@decorators.task
 def call_suzzie(context):
     raise IOError("Suzzie not home right now.")
 
@@ -47,4 +48,4 @@ context = {
 try:
     flow.run(context)
 except Exception as e:
-    print("Flow failed: %s" % (e))
+    print "Flow failed: %r" % e

taskflow/examples/simple_linear.out.txt

@@ -0,0 +1,4 @@
+Calling jim.
+Context = {'joe_number': 444, 'jim_number': 555}
+Calling joe.
+Context = {'joe_number': 444, 'jim_number': 555}

taskflow/examples/simple_linear.py

@@ -8,14 +8,17 @@ my_dir_path = os.path.dirname(os.path.abspath(__file__))
 sys.path.insert(0, os.path.join(os.path.join(my_dir_path, os.pardir),
                                 os.pardir))
 
+from taskflow import decorators
 from taskflow.patterns import linear_flow as lf
 
 
+@decorators.task
 def call_jim(context):
     print("Calling jim.")
     print("Context = %s" % (context))
 
 
+@decorators.task
 def call_joe(context):
     print("Calling joe.")
     print("Context = %s" % (context))

taskflow/examples/simple_linear_listening.out.txt

@@ -0,0 +1,18 @@
+Flow "Call-them": PENDING => STARTED
+Flow "Call-them": context={'joe_number': 444, 'jim_number': 555}
+Flow "Call-them": STARTED => RUNNING
+Flow "Call-them": context={'joe_number': 444, 'jim_number': 555}
+Flow "Call-them": runner "__main__.call_jim"
+Flow "Call-them": context={'joe_number': 444, 'jim_number': 555}
+Calling jim.
+Context = {'joe_number': 444, 'jim_number': 555}
+Flow "Call-them": runner "__main__.call_jim"
+Flow "Call-them": context={'joe_number': 444, 'jim_number': 555}
+Flow "Call-them": runner "__main__.call_joe"
+Flow "Call-them": context={'joe_number': 444, 'jim_number': 555}
+Calling joe.
+Context = {'joe_number': 444, 'jim_number': 555}
+Flow "Call-them": runner "__main__.call_joe"
+Flow "Call-them": context={'joe_number': 444, 'jim_number': 555}
+Flow "Call-them": RUNNING => SUCCESS
+Flow "Call-them": context={'joe_number': 444, 'jim_number': 555}

taskflow/examples/simple_linear_listening.py

@@ -8,19 +8,23 @@ my_dir_path = os.path.dirname(os.path.abspath(__file__))
 sys.path.insert(0, os.path.join(os.path.join(my_dir_path, os.pardir),
                                 os.pardir))
 
+from taskflow import decorators
 from taskflow.patterns import linear_flow as lf
 
 
+@decorators.task
 def call_jim(context):
     print("Calling jim.")
     print("Context = %s" % (context))
 
 
+@decorators.task
 def call_joe(context):
     print("Calling joe.")
     print("Context = %s" % (context))
 
 
+@decorators.task
 def flow_watch(state, details):
     flow = details['flow']
     old_state = details['old_state']
@@ -29,6 +33,7 @@ def flow_watch(state, details):
     print('Flow "%s": context=%s' % (flow.name, context))
 
 
+@decorators.task
 def task_watch(state, details):
     flow = details['flow']
     runner = details['runner']
@@ -43,6 +48,7 @@ flow.add(call_joe)
 flow.notifier.register('*', flow_watch)
 flow.task_notifier.register('*', task_watch)
 
+
 context = {
     "joe_number": 444,
     "jim_number": 555,

taskflow/tests/test_examples.py

@@ -0,0 +1,114 @@
+# -*- coding: utf-8 -*-
+
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+#    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.
+
+
+"""Run examples as unit tests
+
+This module executes examples as unit tests, thus ensuring they at least
+can be executed with current taskflow. For examples with deterministic
+output, the output can be put to file with same name and '.out.txt'
+extension; then it will be checked that output did not change.
+
+When this module is used as main module, output for all examples are
+generated. Please note that this will break tests as output for most
+examples is indeterministic.
+"""
+
+
+import os
+import re
+import subprocess
+import sys
+import taskflow.test
+
+ROOT_DIR = os.path.abspath(
+    os.path.dirname(
+        os.path.dirname(
+            os.path.dirname(__file__))))
+
+
+def root_path(*args):
+    return os.path.join(ROOT_DIR, *args)
+
+
+def run_example(name):
+    path = root_path('taskflow', 'examples', '%s.py' % name)
+    obj = subprocess.Popen(
+        [sys.executable, path],
+        stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+    output = obj.communicate()
+    if output[1]:
+        raise RuntimeError('Example wrote to stderr:\n%s' % output[1])
+    return output[0]
+
+
+def expected_output_path(name):
+    return root_path('taskflow', 'examples',
+                     '%s.out.txt' % name)
+
+
+def list_examples():
+    ext = '.py'
+    examples_dir = root_path('taskflow', 'examples')
+    for filename in os.listdir(examples_dir):
+        if filename.endswith(ext):
+            yield filename[:-len(ext)]
+
+
+class ExamplesTestCase(taskflow.test.TestCase):
+    maxDiff = None  # sky's the limit
+
+    uuid_re = re.compile('XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX'
+                         .replace('X', '[0-9a-f]'))
+
+    @classmethod
+    def update(cls):
+        def add_test_method(name, method_name):
+            def test_example(self):
+                self._check_example(name)
+            test_example.__name__ = method_name
+            setattr(cls, method_name, test_example)
+
+        for name in list_examples():
+            add_test_method(name, 'test_%s' % name)
+
+    def _check_example(self, name):
+        output = run_example(name)
+        eop = expected_output_path(name)
+        if os.path.isfile(eop):
+            with open(eop) as f:
+                expected_output = f.read()
+            # NOTE(imelnikov): on each run new uuid is generated, so we just
+            #   replace them with some constant string
+            output = self.uuid_re.sub('<SOME UUID>', output)
+            expected_output = self.uuid_re.sub('<SOME UUID>', expected_output)
+            self.assertMultiLineEqual(output, expected_output)
+
+ExamplesTestCase.update()
+
+
+def make_output_files():
+    """Generate output files for all examples"""
+    for name in list_examples(False):
+        output = run_example(name)
+        with open(expected_output_path(name), 'w') as f:
+            f.write(output)
+
+
+if __name__ == '__main__':
+    make_output_files()