Add a simple test for os.startfile().

Lib/test/empty.vbs

+'Empty VBS file, does nothing.  Helper for Lib\test\test_startfile.py.
\ No newline at end of file

Lib/test/test_startfile.py

+# Ridiculously simple test of the os.startfile function for Windows.
+#
+# empty.vbs is an empty file (except for a comment), which does
+# nothing when run with cscript or wscript.
+#
+# A possible improvement would be to have empty.vbs do something that
+# we can detect here, to make sure that not only the os.startfile()
+# call succeeded, but also the the script actually has run.
+
+import unittest
+from test import test_support
+import os
+
+
+class TestCase(unittest.TestCase):
+    def test_nonexisting(self):
+        self.assertRaises(OSError, os.startfile, "nonexisting.vbs")
+
+    def test_nonexisting_u(self):
+        self.assertRaises(OSError, os.startfile, u"nonexisting.vbs")
+
+    def test_empty(self):
+        empty = os.path.join(os.path.dirname(__file__), "empty.vbs")
+        os.startfile(empty)
+        os.startfile(empty, "open")
+
+    def test_empty_u(self):
+        empty = os.path.join(os.path.dirname(__file__), "empty.vbs")
+        os.startfile(unicode(empty, "mbcs"))
+        os.startfile(unicode(empty, "mbcs"), "open")
+
+def test_main():
+    test_support.run_unittest(TestCase)
+
+if __name__=="__main__":
+    test_main()