correctly handle zero length cmdline arguments

CHANGELOG

@@ -1,6 +1,7 @@
 Changes between 2.1.2 and [next version]
 ----------------------------------------
 
+- correctly handle zero length arguments (a la pytest '')
 - fix issue67 / junitxml now contains correct test durations, thanks ronny
 - fix issue75 / skipping test failure on jython
 

_pytest/config.py

@@ -421,7 +421,7 @@ class Config(object):
 
 
 def getcfg(args, inibasenames):
-    args = [x for x in args if str(x)[0] != "-"]
+    args = [x for x in args if not str(x).startswith("-")]
     if not args:
         args = [py.path.local()]
     for arg in args:

testing/test_config.py

@@ -16,6 +16,9 @@ class TestParseIni:
         config._preparse([sub])
         assert config.inicfg['name'] == 'value'
 
+    def test_getcfg_empty_path(self, tmpdir):
+        cfg = getcfg([''], ['setup.cfg']) #happens on py.test  ""
+
     def test_append_parse_args(self, tmpdir):
         tmpdir.join("setup.cfg").write(py.code.Source("""
             [pytest]