openfiles: add tests and close files

Added a functional test and included a close() call on files that are
opened when the module/test run.

i3pystatus/openfiles.py

@@ -18,8 +18,9 @@ class Openfiles(IntervalModule):
 
     def run(self):
 
-        cur_filenr = open(self.filenr_path, 'r').readlines()
+        cur_filenr = open(self.filenr_path, 'r')
-        openfiles, unused, maxfiles = cur_filenr[0].split()
+        openfiles, unused, maxfiles = cur_filenr.readlines()[0].split()
+        cur_filenr.close()
 
         cdict = {'openfiles': openfiles,
                  'maxfiles': maxfiles}

tests/test_openfiles.py

@@ -0,0 +1,29 @@
+"""
+Basic test for the openfiles module
+"""
+
+import unittest
+from tempfile import TemporaryDirectory
+from shutil import copyfile
+from i3pystatus import openfiles
+
+
+class OpenfilesTest(unittest.TestCase):
+
+    def test_openfiles(self):
+        """
+        Test output of open files
+        """
+        # copy file-nr so we have a known/unchanged source file
+        with TemporaryDirectory() as tmpdirname:
+            copyfile('/proc/sys/fs/file-nr', tmpdirname + '/file-nr')
+            cur_filenr = open(tmpdirname + '/file-nr', 'r')
+            openfilehandles, ununsed, maxfiles = cur_filenr.readlines()[0].split()
+            cur_filenr.close()
+            i3openfiles = openfiles.Openfiles(filenr_path=tmpdirname + '/file-nr')
+            i3openfiles.run()
+            self.assertTrue(i3openfiles.output['full_text'] == 'open/max: %s/%s' % (openfilehandles, maxfiles))
+
+
+if __name__ == '__main__':
+    unittest.main()