From 6237465a344fd97d561f0175e770a4c59dd745a6 Mon Sep 17 00:00:00 2001
From: Keith Mosher <kmosher@yelp.com>
Date: Thu, 12 Feb 2015 00:42:27 -0800
Subject: [PATCH] Fix crash when tracking mtime of 0 files

---
 staticconf/config.py |  2 ++
 tests/config_test.py | 34 ++++++++++++++++++++++++++++++++++
 2 files changed, 36 insertions(+)

diff --git a/staticconf/config.py b/staticconf/config.py
index eeb304a..a3545ca 100644
--- a/staticconf/config.py
+++ b/staticconf/config.py
@@ -414,6 +414,8 @@ def __init__(self, filenames):
         self.last_max_mtime = self.get_most_recent_changed()
 
     def get_most_recent_changed(self):
+        if not self.filenames:
+            return -1
         return max(os.path.getmtime(name) for name in self.filenames)
 
     def has_changed(self):
diff --git a/tests/config_test.py b/tests/config_test.py
index 2b123f7..d27797d 100644
--- a/tests/config_test.py
+++ b/tests/config_test.py
@@ -388,6 +388,10 @@ def test_reload_custom(self):
 
 class TestInodeComparator(object):
 
+    def test_get_inodes_empty(self):
+        comparator = config.InodeComparator([])
+        assert comparator.get_inodes() == []
+
     @mock.patch('staticconf.config.os.stat', autospec=True)
     def test_get_inodes(self, mock_stat):
         comparator = config.InodeComparator(['./one.file'])
@@ -396,6 +400,32 @@ def test_get_inodes(self, mock_stat):
         assert_equal(inodes, expected)
 
 
+class TestMTimeComparator(object):
+
+    def test_get_most_recent_empty(self):
+        comparator = config.MTimeComparator([])
+        assert comparator.get_most_recent_changed() == -1
+
+    @mock.patch('staticconf.config.os.path.getmtime', autospec=True, side_effect=[0,0,1,2,3])
+    def test_get_most_recent(self, mock_mtime):
+        comparator = config.MTimeComparator(['./one.file', './two.file'])
+        assert comparator.get_most_recent_changed() == 2
+        assert mock_mtime.call_count == 4
+
+    @mock.patch('staticconf.config.os.path.getmtime', autospec=True, return_value=1)
+    def test_no_change(self, mock_mtime):
+        comparator = config.MTimeComparator(['./one.file'])
+        assert not comparator.has_changed()
+        assert not comparator.has_changed()
+
+    @mock.patch('staticconf.config.os.path.getmtime', autospec=True, side_effect=[0,1,1,2])
+    def test_changes(self, mock_mtime):
+        comparator = config.MTimeComparator(['./one.file'])
+        assert comparator.has_changed()
+        assert not comparator.has_changed()
+        assert comparator.has_changed()
+
+
 class TestMD5Comparator(object):
 
     @pytest.yield_fixture()
@@ -410,6 +440,10 @@ def write_contents(self, contents):
         self.file.write(contents)
         self.file.flush()
 
+    def test_get_hashes_empty(self):
+        comparator = config.MD5Comparator([])
+        assert comparator.get_hashes() == []
+
     def test_has_changed_no_changes(self, comparator):
         assert not comparator.has_changed()
         self.write_contents(self.original_contents)