added new function file.no_of_shards + tests.

	modified:   combox/file.py
	modified:   tests/file_test.py

2 files changed, 46 insertions, 0 deletions

diff --git a/combox/file.py b/combox/file.py
index 81d15fe..a8e345b 100644
--- a/combox/file.py
+++ b/combox/file.py
@@ -420,3 +420,19 @@ def read_shards(directories, shard_basename):
         shards.append(shard_content)
 
     return shards
+
+
+def no_of_shards(cb_path, config):
+    """Returns the no. of shards that exists for `cb_path' in node directories.
+
+    cb_path: path to file in combox directory.
+    """
+
+    no_shards_there = 0
+    shard_paths = node_paths(cb_path, config, isfile=True)
+
+    for shard in shard_paths:
+        if path.isfile(shard):
+            no_shards_there += 1
+
+    return no_shards_there
diff --git a/tests/file_test.py b/tests/file_test.py
index d8a77ca..f3a153d 100644
--- a/tests/file_test.py
+++ b/tests/file_test.py
@@ -222,6 +222,36 @@ class TestFile(object):
         self.purge_list.append(new_dir)
 
 
+    def test_noofshards(self):
+        """Tests the node_paths function."""
+        nodes = get_nodedirs(self.config)
+        node_iter = iter(nodes)
+        lorem = path.join(self.config['combox_dir'], 'lorem.txt')
+
+        # get the shards on the node directories
+        split_and_encrypt(lorem, self.config)
+
+        # no. of shards must be equal to no. of node directories.
+        assert_equal(no_of_shards(lorem, self.config),
+                     len(nodes))
+
+        n_paths = node_paths(lorem, self.config, isfile=True)
+
+        # now remove first shard
+        rm_path(n_paths[0])
+        # no. of shards must be equal to one less than the no. of node
+        # directories.
+        assert_equal(no_of_shards(lorem, self.config),
+                     len(nodes) - 1)
+
+        # now remove second shard
+        rm_path(n_paths[1])
+        # no. of shards must be equal to two less than the no. of node
+        # directories.
+        assert_equal(no_of_shards(lorem, self.config),
+                     len(nodes) - 2)
+
+
     def teardown(self):
         """Cleans up things after each test in this class."""
         purge(self.purge_list)