unit tests on 'buildslave upgrade' command

Test that older buildbot.tac files are updated correctly.
Test that modern buildbot.tac files are not changed.

slave/buildslave/test/unit/test_scripts_upgrade_slave.py

@@ -13,15 +13,42 @@
 #
 # Copyright Buildbot Team Members
 
+import os
+import mock
 from twisted.trial import unittest
 from buildslave.scripts import upgrade_slave
 from buildslave.test.util import misc
 
+MODERN_BUILDBOT_TAC = \
+"""# dummy buildbot.tac
+import os
 
-class TestUpgradeSlave(misc.IsBuildslaveDirMixin, unittest.TestCase):
+from buildslave.bot import BuildSlave
+"""
+
+OLD_BUILDBOT_TAC = \
+"""# dummy buildbot.tac
+import os
+
+from buildbot.slave.bot import BuildSlave
+"""
+
+
+class TestUpgradeSlave(misc.IsBuildslaveDirMixin,
+                       misc.StdoutAssertionsMixin,
+                       misc.OpenFileMixin,
+                       unittest.TestCase):
     """
     Test buildslave.scripts.runner.upgradeSlave()
     """
+    config = {"basedir": "dummy"}
+
+    def setUp(self):
+        self.setUpStdoutAssertions()
+
+        # expected buildbot.tac relative path
+        self.buildbot_tac = os.path.join(self.config["basedir"],
+                                         "buildbot.tac")
 
     def test_upgradeSlave_bad_basedir(self):
         """
@@ -31,9 +58,58 @@ def test_upgradeSlave_bad_basedir(self):
         self.setupUpIsBuildslaveDir(False)
 
         # call upgradeSlave() and check that correct exit code is returned
-        config = {"basedir": "dummy"}
-        self.assertEqual(upgrade_slave.upgradeSlave(config), 1,
+        self.assertEqual(upgrade_slave.upgradeSlave(self.config), 1,
                          "unexpected exit code")
 
         # check that isBuildslaveDir was called with correct argument
         self.isBuildslaveDir.assert_called_once_with("dummy")
+
+    def test_upgradeSlave_no_changes(self):
+        """
+        test calling upgradeSlave() on a buildbot.tac that don't need to be
+        upgraded
+        """
+        # patch basedir check to always succeed
+        self.setupUpIsBuildslaveDir(True)
+
+        # patch open() to return a modern buildbot.tac file
+        self.setUpOpen(MODERN_BUILDBOT_TAC)
+
+        # call upgradeSlave() and check the success exit code is returned
+        self.assertEqual(upgrade_slave.upgradeSlave(self.config), 0,
+                         "unexpected exit code")
+
+        # check message to stdout
+        self.assertStdoutEqual("No changes made\n")
+
+        # check that open() was called with correct path
+        self.open.assert_called_once_with(self.buildbot_tac)
+
+        # check that no writes where made
+        self.assertFalse(self.fileobj.write.called,
+                         "unexpected write to buildbot.tac file")
+
+    def test_upgradeSlave_updated(self):
+        """
+        test calling upgradeSlave() on an older buildbot.tac, that need to
+        be updated
+        """
+        # patch basedir check to always succeed
+        self.setupUpIsBuildslaveDir(True)
+
+        # patch open() to return older buildbot.tac file
+        self.setUpOpen(OLD_BUILDBOT_TAC)
+
+        # call upgradeSlave() and check the success exit code is returned
+        self.assertEqual(upgrade_slave.upgradeSlave(self.config), 0,
+                         "unexpected exit code")
+
+        # check message to stdout
+        self.assertStdoutEqual("buildbot.tac updated\n")
+
+        # check calls to open()
+        self.open.assert_has_calls([mock.call(self.buildbot_tac),
+                                    mock.call(self.buildbot_tac, "w")])
+
+        # check that we wrote correct updated buildbot.tac file
+        self.fileobj.write.assert_called_once_with(MODERN_BUILDBOT_TAC)

slave/buildslave/test/util/misc.py

@@ -81,8 +81,10 @@ def setUpOpen(self, file_contents):
                               read() method
         """
         # create mocked file object that returns 'file_contents' on read()
+        # and tracks any write() calls
         self.fileobj = mock.Mock()
         self.fileobj.read = mock.Mock(return_value=file_contents)
+        self.fileobj.write = mock.Mock()
 
         # patch open() to return mocked object
         self.open = mock.Mock(return_value=self.fileobj)