Fix priority of Alert pane (#1422)

* Fix priority of Alert pane

* Fixed flakes

* Fixed Alert API

* Fix kwargs of Alert

panel/pane/__init__.py

@@ -8,7 +8,7 @@
 from __future__ import absolute_import, division, unicode_literals
 
 from .ace import Ace # noqa
-from .alert import Alert
+from .alert import Alert # noqa
 from .base import PaneBase, Pane, panel # noqa
 from .equation import LaTeX # noqa
 from .deckgl import DeckGL # noqa

panel/pane/alert.py

@@ -19,22 +19,17 @@ class Alert(Markdown):
 
     alert_type = param.ObjectSelector("primary", objects=ALERT_TYPES)
 
-    def __init__(self, text: str, **kwargs):
-        """An Primary Alert that renders Markdown
-
-        - CSS Styling is done via the classes `alert` and `alert-primary`.
-        - sizing_mode is set to `stretch_width` by default
-
-        Arguments:
-            text {str} -- Some MarkDown text
-        """
-        if "margin" not in kwargs:
-            kwargs["margin"] = (0, 0, 25, 0)
-        if "sizing_mode" not in kwargs:
-            kwargs["sizing_mode"] = "stretch_width"
-
-        super().__init__(text, **kwargs)
-
+    @classmethod
+    def applies(cls, obj):
+        priority = Markdown.applies(obj)
+        return 0 if priority else False
+
+    def __init__(self, object=None, **params):
+        if "margin" not in params:
+            params["margin"] = (0, 0, 25, 0)
+        if "sizing_mode" not in params:
+            params["sizing_mode"] = "stretch_width"
+        super().__init__(object, **params)
         self._set_css_classes()
 
     @param.depends("alert_type", watch=True)

panel/tests/pane/test_alert.py

@@ -2,6 +2,7 @@
 import pytest
 
 import panel as pn
+
 from panel.pane import Alert
 from panel.pane.alert import ALERT_TYPES
 
@@ -28,7 +29,7 @@ def test_existing_css_classes():
     assert set(alert.css_classes) == {"alert", f"alert-{Alert.param.alert_type.default}", "important"}
 
     alert.alert_type="info"
-    assert set(alert.css_classes) == {"alert", f"alert-info", "important"}
+    assert set(alert.css_classes) == {"alert", "alert-info", "important"}
 
 
 def test_all_view():
@@ -48,4 +49,4 @@ def test_all_view():
 
 
 if __name__.startswith("bk"):
-    test_all_view().servable()
+    test_all_view().servable()