Added a working unit test of commands.main().

tests/test_commands.py

+# coding: utf-8
+
+"""
+Unit tests of commands.py.
+
+"""
+
+import sys
+import unittest
+
+from pystache.commands import main
+
+
+ORIGINAL_STDOUT = sys.stdout
+
+
+class MockStdout(object):
+
+    def __init__(self):
+        self.output = ""
+
+    def write(self, str):
+        self.output += str
+
+
+class CommandsTestCase(unittest.TestCase):
+
+    def setUp(self):
+        sys.stdout = MockStdout()
+
+    def callScript(self, template, context):
+        argv = ['pystache', template, context]
+        main(argv)
+        return sys.stdout.output
+
+    def testMainSimple(self):
+        """
+        Test a simple command-line case.
+
+        """
+        actual = self.callScript("Hi {{thing}}", '{"thing": "world"}')
+        self.assertEquals(actual, u"Hi world\n")
+
+    def tearDown(self):
+        sys.stdout = ORIGINAL_STDOUT