Improve the catching of calls to 'execute' related functions

Improve the catching of calls to 'execute' related functions in unit
tests. Before we only caught calls to utils.execute(). Now we catch
calls to:

    ironic_lib.utils.execute()
    processutils.execute()
    subprocess.call()
    subprocess.check_call()
    subprocess.check_output()
    utils.execute()

Change-Id: If4720ebed00f15c2a19cb8badbe4dc3c808eeece

2 files changed, 30 insertions, 13 deletions

diff --git a/ironic_python_agent/tests/unit/base.py b/ironic_python_agent/tests/unit/base.py
index 11fff16b..97d1bfe2 100644
--- a/ironic_python_agent/tests/unit/base.py
+++ b/ironic_python_agent/tests/unit/base.py
@@ -15,8 +15,11 @@
 
 """Common utilities and classes across all unit tests."""
 
-import mock
+import subprocess
 
+import ironic_lib
+import mock
+from oslo_concurrency import processutils
 from oslotest import base as test_base
 
 from ironic_python_agent import utils
@@ -25,19 +28,33 @@ from ironic_python_agent import utils
 class IronicAgentTest(test_base.BaseTestCase):
     """Extends the base test to provide common features across agent tests."""
 
+    # By default block execution of utils.execute() and related functions.
+    block_execute = True
+
     def setUp(self):
         super(IronicAgentTest, self).setUp()
-        """Add a blanket ban on running external processes via utils.execute().
+        """Ban running external processes via 'execute' like functions
 
         `self` will grow a property  called _exec_patch which is the Mock
-        that replaces utils.execute.
+        that replaces all the 'execute' related functions.
 
         If the mock is called, an exception is raised to warn the tester.
         """
         # NOTE(bigjools): Not using a decorator on tests because I don't
         # want to force every test method to accept a new arg. Instead, they
         # can override or examine this self._exec_patch Mock as needed.
-        self._exec_patch = mock.Mock()
-        self._exec_patch.side_effect = Exception(
-            "Don't call utils.execute in tests!")
-        self.patch(utils, 'execute', self._exec_patch)
+        if self.block_execute:
+            self._exec_patch = mock.Mock()
+            self._exec_patch.side_effect = Exception(
+                "Don't call ironic_lib.utils.execute() / "
+                "processutils.execute() or similar functions in tests!")
+
+            # NOTE(jlvillal): pyudev.Context() calls ctypes.find_library()
+            # which calls subprocess.Popen(). So not blocking
+            # subprocess.Popen()
+            self.patch(ironic_lib.utils, 'execute', self._exec_patch)
+            self.patch(processutils, 'execute', self._exec_patch)
+            self.patch(subprocess, 'call', self._exec_patch)
+            self.patch(subprocess, 'check_call', self._exec_patch)
+            self.patch(subprocess, 'check_output', self._exec_patch)
+            self.patch(utils, 'execute', self._exec_patch)
diff --git a/ironic_python_agent/tests/unit/test_utils.py b/ironic_python_agent/tests/unit/test_utils.py
index 31c9988b..8fe8ee53 100644
--- a/ironic_python_agent/tests/unit/test_utils.py
+++ b/ironic_python_agent/tests/unit/test_utils.py
@@ -26,7 +26,6 @@ from ironic_lib import utils as ironic_utils
 import mock
 from oslo_concurrency import processutils
 from oslo_serialization import base64
-from oslotest import base as test_base
 import six
 import testtools
 
@@ -35,12 +34,13 @@ from ironic_python_agent.tests.unit import base as ironic_agent_base
 from ironic_python_agent import utils
 
 
-# Normally we'd use the IronicAgentTest base class which mocks out
-# any use of utils.execute() to prevent accidental processes. However
-# this test is checking the upcall to ironic_lib's execute(), so that
-# is mocked out instead.
-class ExecuteTestCase(test_base.BaseTestCase):
+class ExecuteTestCase(ironic_agent_base.IronicAgentTest):
+    # This test case does call utils.execute(), so don't block access to the
+    # execute calls.
+    block_execute = False
 
+    # We do mock out the call to ironic_utils.execute() so we don't actually
+    # 'execute' anything, as utils.execute() calls ironic_utils.execute()
     @mock.patch.object(ironic_utils, 'execute', autospec=True)
     def test_execute(self, mock_execute):
         utils.execute('/usr/bin/env', 'false', check_exit_code=False)