From 3fdfa3248d1bd838fee88af6a277bf94eeaad87a Mon Sep 17 00:00:00 2001
From: Philipp Rudiger <prudiger@anaconda.com>
Date: Mon, 2 Nov 2020 10:38:00 +0100
Subject: [PATCH] Fix changing of alert_type on Alert pane (#1734)

* Fix changing of alert_type on Alert pane

* Fixed Markdown test
---
 panel/pane/alert.py            | 2 +-
 panel/pane/markup.py           | 2 +-
 panel/tests/pane/test_alert.py | 6 +++++-
 panel/tests/util.py            | 7 ++++++-
 4 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/panel/pane/alert.py b/panel/pane/alert.py
index d9d279a27c..d9cb1b2acb 100644
--- a/panel/pane/alert.py
+++ b/panel/pane/alert.py
@@ -21,7 +21,7 @@ class Alert(Markdown):
 
     priority = 0
 
-    _rename=dict(Markdown._rename, alert_type=None)
+    _rename = dict(Markdown._rename, alert_type=None)
 
     @classmethod
     def applies(cls, obj):
diff --git a/panel/pane/markup.py b/panel/pane/markup.py
index 487172ff4c..fbdf2af23b 100644
--- a/panel/pane/markup.py
+++ b/panel/pane/markup.py
@@ -269,7 +269,7 @@ class Markdown(DivPaneBase):
 
     _target_transforms = {'object': None}
 
-    _rerender_params = ['object', 'dedent', 'extensions']
+    _rerender_params = ['object', 'dedent', 'extensions', 'css_classes']
 
     @classmethod
     def applies(cls, obj):
diff --git a/panel/tests/pane/test_alert.py b/panel/tests/pane/test_alert.py
index 03df660629..6431c325d2 100644
--- a/panel/tests/pane/test_alert.py
+++ b/panel/tests/pane/test_alert.py
@@ -16,13 +16,17 @@ def test_constructor():
 
 
 @pytest.mark.parametrize(["alert_type"], [(alert_type,) for alert_type in ALERT_TYPES])
-def test_alert_type_change(alert_type):
+def test_alert_type_change(alert_type, document, comm):
     """Test that an alert can change alert_type"""
     alert = Alert(text="This is some text")
 
+    model = alert.get_root(document, comm)
+
     alert.alert_type = alert_type
     assert set(alert.css_classes) == {"alert", f"alert-{alert_type}"}
+    assert set(model.css_classes) == {"alert", f"alert-{alert_type}", "markdown"}
 
+    
 def test_existing_css_classes():
     """Test that an alert can change alert_type"""
     alert = Alert(text="This is some text", css_classes=["important"])
diff --git a/panel/tests/util.py b/panel/tests/util.py
index e99c44255a..8442bc1815 100644
--- a/panel/tests/util.py
+++ b/panel/tests/util.py
@@ -41,6 +41,8 @@
 
 py3_only = pytest.mark.skipif(sys.version_info.major < 3, reason="requires Python 3")
 
+from panel.pane.markup import Markdown
+
 
 def mpl_figure():
     import matplotlib.pyplot as plt
@@ -56,7 +58,10 @@ def check_layoutable_properties(layoutable, model):
     assert model.background == '#ffffff'
 
     layoutable.css_classes = ['custom_class']
-    assert model.css_classes == ['custom_class']
+    if isinstance(layoutable, Markdown):
+        assert model.css_classes == ['custom_class', 'markdown']
+    else:
+        assert model.css_classes == ['custom_class']
 
     layoutable.width = 500
     assert model.width == 500