Make discovery to work with no IP addr and token, courtesy of M0ses (#…

…198)

* Make discovery to work with no IP addr and token

Obsoletes #194

* Fix linting

* Add simple tests for click_common's validators, code courtesy of M0ses

* make linter happy

miio/click_common.py

@@ -17,6 +17,8 @@
 
 
 def validate_ip(ctx, param, value):
+    if value is None:
+        return None
     try:
         ipaddress.ip_address(value)
         return value
@@ -25,6 +27,8 @@ def validate_ip(ctx, param, value):
 
 
 def validate_token(ctx, param, value):
+    if value is None:
+        return None
     token_len = len(value)
     if token_len != 32:
         raise click.BadParameter("Token length != 32 chars: %s" % token_len)

miio/tests/test_click_common.py

@@ -0,0 +1,10 @@
+from miio.click_common import validate_token, validate_ip
+
+
+def test_validate_token_empty():
+    assert not validate_token(None, None, None)
+
+
+def test_validate_ip_empty():
+    assert validate_ip(None, None, None) is None
+