Add no hard link support for ln

tests/rules/test_ln_no_hard_link.py

@@ -0,0 +1,45 @@
+from thefuck.rules.ln_no_hard_link import match, get_new_command
+from tests.utils import Command
+
+
+def test_match():
+    err = "hard link not allowed for directory"
+    assert not match(Command())
+
+    cmd1 = Command("ln barDir barLink", stderr="ln: ‘barDir’: {}".format(err))
+    assert match(cmd1)
+
+    cmd2 = Command("sudo ln a b", stderr="ln: ‘a’: {}".format(err))
+    assert match(cmd2)
+
+    cmd3 = Command("ln a b", stderr="... hard link")
+    assert not match(cmd3)
+
+    cmd4 = Command("sudo ln a b", stderr="... hard link")
+    assert not match(cmd4)
+
+    cmd5 = Command("a b", stderr=err)
+    assert not match(cmd5)
+
+    cmd6 = Command("sudo ln -nbi a b", stderr="ln: ‘a’: {}".format(err))
+    assert match(cmd6)
+
+
+def test_get_new_command():
+    cmd1 = Command("ln barDir barLink")
+    assert get_new_command(cmd1) == "ln -s barDir barLink"
+
+    cmd2 = Command("sudo ln barDir barLink")
+    assert get_new_command(cmd2) == "sudo ln -s barDir barLink"
+
+    cmd3 = Command("sudo ln -nbi a b")
+    assert get_new_command(cmd3) == "sudo ln -s -nbi a b"
+
+    cmd4 = Command("ln -nbi a b && ls")
+    assert get_new_command(cmd4) == "ln -s -nbi a b && ls"
+
+    cmd5 = Command("ln a ln")
+    assert get_new_command(cmd5) == "ln -s a ln"
+
+    cmd6 = Command("sudo ln a ln")
+    assert get_new_command(cmd6) == "sudo ln -s a ln"