Create chunks, strata in cache via temporary files

This avoids problems with files with the right names but partial
content, if morph is killed in the middle of writing the file.

1 files changed, 90 insertions, 0 deletions

diff --git a/morphlib/savefile_tests.py b/morphlib/savefile_tests.py
new file mode 100644
index 00000000..442a0779
--- /dev/null
+++ b/morphlib/savefile_tests.py
@@ -0,0 +1,90 @@
+# Copyright (C) 2012  Codethink Limited
+# 
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; version 2 of the License.
+# 
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+# 
+# You should have received a copy of the GNU General Public License along
+# with this program; if not, write to the Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+
+import os
+import shutil
+import tempfile
+import unittest
+
+import savefile
+
+
+class SaveFileTests(unittest.TestCase):
+
+    def cat(self, filename):
+        with open(filename) as f:
+            return f.read()
+
+    def mkfile(self, filename, contents):
+        with open(filename, 'w') as f:
+            f.write(contents)
+
+    def setUp(self):
+        self.tempdir = tempfile.mkdtemp()
+        self.basename = 'filename'
+        self.filename = os.path.join(self.tempdir, self.basename)
+        
+    def tearDown(self):
+        shutil.rmtree(self.tempdir)
+    
+    def test_there_are_no_files_initially(self):
+        self.assertEqual(os.listdir(self.tempdir), [])
+
+    def test_saves_new_file(self):
+        f = savefile.SaveFile(self.filename, 'w')
+        f.write('foo')
+        f.close()
+        self.assertEqual(os.listdir(self.tempdir), [self.basename])
+        self.assertEqual(self.cat(self.filename), 'foo')
+
+    def test_overwrites_existing_file(self):
+        self.mkfile(self.filename, 'yo!')
+        f = savefile.SaveFile(self.filename, 'w')
+        f.write('foo')
+        f.close()
+        self.assertEqual(os.listdir(self.tempdir), [self.basename])
+        self.assertEqual(self.cat(self.filename), 'foo')
+
+    def test_leaves_no_file_after_aborted_new_file(self):
+        f = savefile.SaveFile(self.filename, 'w')
+        f.write('foo')
+        f.abort()
+        self.assertEqual(os.listdir(self.tempdir), [])
+
+    def test_leaves_original_file_after_aborted_overwrite(self):
+        self.mkfile(self.filename, 'yo!')
+        f = savefile.SaveFile(self.filename, 'w')
+        f.write('foo')
+        f.abort()
+        self.assertEqual(os.listdir(self.tempdir), [self.basename])
+        self.assertEqual(self.cat(self.filename), 'yo!')
+
+    def test_saves_normally_with_with(self):
+        with savefile.SaveFile(self.filename, 'w') as f:
+            f.write('foo')
+        self.assertEqual(os.listdir(self.tempdir), [self.basename])
+        self.assertEqual(self.cat(self.filename), 'foo')
+
+    def test_saves_normally_with_exception_within_with(self):
+        try:
+            with savefile.SaveFile(self.filename, 'w') as f:
+                f.write('foo')
+                raise Exception()
+        except Exception:
+            pass
+        self.assertEqual(os.listdir(self.tempdir), [self.basename])
+        self.assertEqual(self.cat(self.filename), 'foo')
+