Add a LocalRepoCache class

Jannis and I discussed a refactoring of most of morph's internals
to reduce coupling and increase cohesion. This is one of the results:
we'll want a couple of classes to manage locally cached git repositories.
This commit adds the LocalRepoCache class to manage a the git cache
directory. Later on, we'll add the CachedRepo class to represent
individual repositories.

1 files changed, 98 insertions, 0 deletions

diff --git a/morphlib/localrepocache_tests.py b/morphlib/localrepocache_tests.py
new file mode 100644
index 00000000..13a1c415
--- /dev/null
+++ b/morphlib/localrepocache_tests.py
@@ -0,0 +1,98 @@
+# 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 unittest
+
+import morphlib
+
+
+class LocalRepoCacheTests(unittest.TestCase):
+
+    def setUp(self):
+        baseurls = ['git://example.com/']
+        self.reponame = 'reponame'
+        self.repourl = 'git://example.com/reponame'
+        self.cachedir = '/cache/dir'
+        self.cache = set()
+        self.remotes = []
+        self.lrc = morphlib.localrepocache.LocalRepoCache(self.cachedir,
+                                                          baseurls)
+        self.lrc._git = self.fake_git
+        self.lrc._exists = self.fake_exists
+        
+    def fake_git(self, args):
+        if args[0] == 'clone':
+            self.assertEqual(len(args), 3)
+            remote = args[1]
+            local = args[2]
+            if local in self.cache:
+                raise Exception('cloning twice to %s' % local)
+            self.remotes.append(remote)
+            self.cache.add(local)
+        else:
+            raise NotImplementedError()
+        
+    def fake_exists(self, filename):
+        return filename in self.cache
+
+    def test_has_not_got_relative_repo_initially(self):
+        self.assertFalse(self.lrc.has_repo(self.reponame))
+
+    def test_has_not_got_absolute_repo_initially(self):
+        self.assertFalse(self.lrc.has_repo(self.repourl))
+
+    def test_caches_relative_repository_on_request(self):
+        self.lrc.cache_repo(self.reponame)
+        self.assertTrue(self.lrc.has_repo(self.reponame))
+        self.assertTrue(self.lrc.has_repo(self.repourl))
+
+    def test_caches_absolute_repository_on_request(self):
+        self.lrc.cache_repo(self.repourl)
+        self.assertTrue(self.lrc.has_repo(self.reponame))
+        self.assertTrue(self.lrc.has_repo(self.repourl))
+
+    def test_happily_caches_same_repo_twice(self):
+        self.lrc.cache_repo(self.repourl)
+        self.lrc.cache_repo(self.repourl)
+
+    def test_fails_to_cache_when_remote_does_not_exist(self):
+        def fail(args):
+            raise morphlib.execute.CommandFailure('', '')
+        self.lrc._git = fail
+        self.assertRaises(morphlib.localrepocache.NoRemote, 
+                          self.lrc.cache_repo, self.repourl)
+
+    def test_gets_cached_relative_repo(self):
+        self.lrc.cache_repo(self.reponame)
+        cached = self.lrc.get_repo(self.reponame)
+        self.assertTrue(cached is not None)
+
+    def test_gets_cached_absolute_repo(self):
+        self.lrc.cache_repo(self.repourl)
+        cached = self.lrc.get_repo(self.repourl)
+        self.assertTrue(cached is not None)
+
+    def test_get_repo_raises_exception_if_repo_is_not_cached(self):
+        self.assertRaises(Exception, self.lrc.get_repo, self.repourl)
+
+    def test_escapes_repourl_as_filename(self):
+        escaped = self.lrc._escape(self.repourl)
+        self.assertFalse('/' in escaped)
+
+    def test_noremote_error_message_contains_repo_name(self):
+        e = morphlib.localrepocache.NoRemote(self.repourl)
+        self.assertTrue(self.repourl in str(e))
+