Add support of lein "is not task"

tests/rules/test_lein_not_task.py

@@ -0,0 +1,22 @@
+import pytest
+from mock import Mock
+from thefuck.rules.lein_not_task import match, get_new_command
+
+
+@pytest.fixture
+def is_not_task():
+    return ''''rpl' is not a task. See 'lein help'.
+
+Did you mean this?
+         repl
+'''
+
+
+def test_match(is_not_task):
+    assert match(Mock(script='lein rpl', stderr=is_not_task), None)
+    assert not match(Mock(script='ls', stderr=is_not_task), None)
+
+
+def test_get_new_command(is_not_task):
+    assert get_new_command(Mock(script='lein rpl --help', stderr=is_not_task),
+                           None) == 'lein repl --help'