Allow other icon prefixes than mdi: (#19872)

homeassistant/helpers/config_validation.py

@@ -200,10 +200,10 @@ def icon(value):
     """Validate icon."""
     value = str(value)
 
-    if value.startswith('mdi:'):
+    if ':' in value:
         return value
 
-    raise vol.Invalid('Icons should start with prefix "mdi:"')
+    raise vol.Invalid('Icons should be specifed on the form "prefix:name"')
 
 
 time_period_dict = vol.All(

tests/helpers/test_config_validation.py

@@ -258,11 +258,12 @@ def test_icon():
     """Test icon validation."""
     schema = vol.Schema(cv.icon)
 
-    for value in (False, 'work', 'icon:work'):
+    for value in (False, 'work'):
         with pytest.raises(vol.MultipleInvalid):
             schema(value)
 
     schema('mdi:work')
+    schema('custom:prefix')
 
 
 def test_time_period():