Heatmap default options (#640)

* Heatmap default options

* update changelog

---------

Co-authored-by: Sergey Galkin <v.sergey.galkin@reddit.com>

Author: fred84

CHANGELOG.rst

@@ -10,6 +10,7 @@ Changelog
 .. _`docs`: https://grafana.com/docs/grafana/latest/dashboards/build-dashboards/manage-dashboard-links/#dashboard-links
 
 * Added ...
+* Fix default options for Heatmap
 * Add Unit option for Graph panel
 * Added Minimum option for Timeseries
 * Added Maximum option for Timeseries

grafanalib/core.py

@@ -3561,7 +3561,7 @@ class Heatmap(Panel):
     heatmap = {}
     hideZeroBuckets = attr.ib(default=False)
     highlightCards = attr.ib(default=True)
-    options = attr.ib(default=None)
+    options = attr.ib(default=attr.Factory(list))
 
     xAxis = attr.ib(
         default=attr.Factory(XAxis),

grafanalib/tests/test_core.py

@@ -1192,6 +1192,12 @@ def test_sql_target_with_source_files():
     print(t.to_json_data()["targets"][0])
 
 
+def test_default_heatmap():
+    h = G.Heatmap()
+
+    assert h.to_json_data()["options"] == []
+
+
 class TestDashboardLink():
 
     def test_validators(self):