Improve unit test coverage per bug/934566.

bug/934566 identified an error which should have been caught by
more complete unit test coverage. This review extends unit test
coverage to include handle_base_image and is one of a series I
will be sending.

Change-Id: I287fc50ea6a92239f11a107f65da84d3ff0c8b3b

nova/tests/test_imagecache.py

@@ -30,6 +30,7 @@ from nova import test
 from nova import db
 from nova import flags
 from nova import log
+from nova import utils
 from nova.virt.libvirt import imagecache
 from nova.virt.libvirt import utils as virtutils
 
@@ -279,12 +280,21 @@ class ImageCacheManagerTestCase(test.TestCase):
                                 (base_file2, True, False),
                                 (base_file3, False, True)])
 
+    def _intercept_log_messages(self):
+        mylog = log.getLogger()
+        stream = cStringIO.StringIO()
+        handler = logging.StreamHandler(stream)
+        handler.setFormatter(log.LegacyNovaFormatter())
+        mylog.logger.addHandler(handler)
+        return mylog, handler, stream
+
     def test_verify_checksum(self):
         testdata = ('OpenStack Software delivers a massively scalable cloud '
                     'operating system.')
         img = {'container_format': 'ami', 'id': '42'}
 
         self.flags(checksum_base_images=True)
+        mylog, handler, stream = self._intercept_log_messages()
 
         try:
             dirname = tempfile.mkdtemp()
@@ -313,6 +323,8 @@ class ImageCacheManagerTestCase(test.TestCase):
             image_cache_manager = imagecache.ImageCacheManager()
             res = image_cache_manager._verify_checksum(img, fname)
             self.assertFalse(res)
+            self.assertNotEqual(stream.getvalue().find('image verification '
+                                                       'failed'), -1)
 
             # Checksum file missing
             os.remove('%s.sha1' % fname)
@@ -326,6 +338,7 @@ class ImageCacheManagerTestCase(test.TestCase):
 
         finally:
             shutil.rmtree(dirname)
+            mylog.logger.removeHandler(handler)
 
     def _make_base_file(checksum=True):
         """Make a base file for testing."""
@@ -333,14 +346,17 @@ class ImageCacheManagerTestCase(test.TestCase):
         dirname = tempfile.mkdtemp()
         fname = os.path.join(dirname, 'aaa')
 
-        f = open(fname, 'w')
+        base_file = open(fname, 'w')
-        f.write('data')
+        base_file.write('data')
-        f.close()
+        base_file.close()
+        base_file = open(fname, 'r')
 
         if checksum:
-            f = open('%s.sha1' % fname, 'w')
+            checksum_file = open('%s.sha1' % fname, 'w')
-            f.close()
+            checksum_file.write(utils.hash_file(base_file))
+            checksum_file.close()
 
+        base_file.close()
         return dirname, fname
 
     def test_remove_base_file(self):
@@ -405,15 +421,8 @@ class ImageCacheManagerTestCase(test.TestCase):
 
     def test_remove_base_file_oserror(self):
         dirname = tempfile.mkdtemp()
-
-        # Intercept log messages
-        mylog = log.getLogger()
-        stream = cStringIO.StringIO()
-        handler = logging.StreamHandler(stream)
-        handler.setFormatter(log.LegacyNovaFormatter())
-        mylog.logger.addHandler(handler)
-
         fname = os.path.join(dirname, 'aaa')
+        mylog, handler, stream = self._intercept_log_messages()
 
         try:
             os.mkdir(fname)
@@ -430,3 +439,134 @@ class ImageCacheManagerTestCase(test.TestCase):
         finally:
             shutil.rmtree(dirname)
             mylog.logger.removeHandler(handler)
+
+    def test_handle_base_image_unused(self):
+        img = {'container_format': 'ami',
+               'id': '123',
+               'uuid': '1234-4567-2378'}
+
+        dirname, fname = self._make_base_file()
+        os.utime(fname, (-1, time.time() - 3601))
+
+        try:
+            image_cache_manager = imagecache.ImageCacheManager()
+            image_cache_manager.unexplained_images = [fname]
+            image_cache_manager._handle_base_image(img, fname)
+
+            self.assertEquals(image_cache_manager.unexplained_images, [])
+            self.assertEquals(image_cache_manager.removable_base_files,
+                              [fname])
+            self.assertEquals(image_cache_manager.corrupt_base_files, [])
+
+        finally:
+            shutil.rmtree(dirname)
+
+    def test_handle_base_image_used(self):
+        img = {'container_format': 'ami',
+               'id': '123',
+               'uuid': '1234-4567-2378'}
+
+        dirname, fname = self._make_base_file()
+        os.utime(fname, (-1, time.time() - 3601))
+
+        try:
+            image_cache_manager = imagecache.ImageCacheManager()
+            image_cache_manager.unexplained_images = [fname]
+            image_cache_manager.used_images = {'123': (1, 0, ['banana-42'])}
+            image_cache_manager._handle_base_image(img, fname)
+
+            self.assertEquals(image_cache_manager.unexplained_images, [])
+            self.assertEquals(image_cache_manager.removable_base_files, [])
+            self.assertEquals(image_cache_manager.corrupt_base_files, [])
+
+        finally:
+            shutil.rmtree(dirname)
+
+    def test_handle_base_image_used_remotely(self):
+        img = {'container_format': 'ami',
+               'id': '123',
+               'uuid': '1234-4567-2378'}
+
+        dirname, fname = self._make_base_file()
+        os.utime(fname, (-1, time.time() - 3601))
+
+        try:
+            image_cache_manager = imagecache.ImageCacheManager()
+            image_cache_manager.used_images = {'123': (0, 1, ['banana-42'])}
+            image_cache_manager._handle_base_image(img, None)
+
+            self.assertEquals(image_cache_manager.unexplained_images, [])
+            self.assertEquals(image_cache_manager.removable_base_files, [])
+            self.assertEquals(image_cache_manager.corrupt_base_files, [])
+
+        finally:
+            shutil.rmtree(dirname)
+
+    def test_handle_base_image_absent(self):
+        """Ensure we warn for use of a missing base image."""
+
+        img = {'container_format': 'ami',
+               'id': '123',
+               'uuid': '1234-4567-2378'}
+
+        mylog, handler, stream = self._intercept_log_messages()
+
+        try:
+            image_cache_manager = imagecache.ImageCacheManager()
+            image_cache_manager.used_images = {'123': (1, 0, ['banana-42'])}
+            image_cache_manager._handle_base_image(img, None)
+
+            self.assertEquals(image_cache_manager.unexplained_images, [])
+            self.assertEquals(image_cache_manager.removable_base_files, [])
+            self.assertEquals(image_cache_manager.corrupt_base_files, [])
+            self.assertNotEqual(stream.getvalue().find('an absent base file'),
+                                -1)
+
+        finally:
+            mylog.logger.removeHandler(handler)
+
+    def test_handle_base_image_used_missing(self):
+        img = {'container_format': 'ami',
+               'id': '123',
+               'uuid': '1234-4567-2378'}
+
+        dirname = tempfile.mkdtemp()
+        fname = os.path.join(dirname, 'aaa')
+
+        try:
+            image_cache_manager = imagecache.ImageCacheManager()
+            image_cache_manager.unexplained_images = [fname]
+            image_cache_manager.used_images = {'123': (1, 0, ['banana-42'])}
+            image_cache_manager._handle_base_image(img, fname)
+
+            self.assertEquals(image_cache_manager.unexplained_images, [])
+            self.assertEquals(image_cache_manager.removable_base_files, [])
+            self.assertEquals(image_cache_manager.corrupt_base_files, [])
+
+        finally:
+            shutil.rmtree(dirname)
+
+    def test_handle_base_image_checksum_fails(self):
+        img = {'container_format': 'ami',
+               'id': '123',
+               'uuid': '1234-4567-2378'}
+
+        dirname, fname = self._make_base_file()
+
+        try:
+            f = open(fname, 'w')
+            f.write('banana')
+            f.close()
+
+            image_cache_manager = imagecache.ImageCacheManager()
+            image_cache_manager.unexplained_images = [fname]
+            image_cache_manager.used_images = {'123': (1, 0, ['banana-42'])}
+            image_cache_manager._handle_base_image(img, fname)
+
+            self.assertEquals(image_cache_manager.unexplained_images, [])
+            self.assertEquals(image_cache_manager.removable_base_files, [])
+            self.assertEquals(image_cache_manager.corrupt_base_files,
+                              [fname])
+
+        finally:
+            shutil.rmtree(dirname)