Add a test for the DRY rule

tests/rules/test_dry.py

@@ -0,0 +1,17 @@
+import pytest
+from thefuck.rules.dry import match, get_new_command
+from tests.utils import Command
+
+
+@pytest.mark.parametrize('command', [
+    Command(script='cd cd foo'),
+    Command(script='git git push origin/master')])
+def test_match(command):
+    assert match(command, None)
+
+
+@pytest.mark.parametrize('command, new_command', [
+    (Command('cd cd foo'), 'cd foo'),
+    (Command('git git push origin/master'), 'git push origin/master')])
+def test_get_new_command(command, new_command):
+    assert get_new_command(command, None) == new_command