Add test for _widget_layout and _widget_data

Author: jescalada

Diff for: tests/test_core/test_figure_widget_backend/test_validate_initialization.py

@@ -0,0 +1,21 @@
+from unittest import TestCase
+import plotly.graph_objs as go
+import pytest
+
+try:
+    go.FigureWidget()
+    figure_widget_available = True
+except ImportError:
+    figure_widget_available = False
+
+
+class TestInitialization(TestCase):
+    if figure_widget_available:
+
+        def test_widget_layout_present_on_init(self):
+            fig = go.FigureWidget(data=go.Scatter(x=[1, 2], y=[1, 2]))
+            assert fig._widget_layout != {}
+
+        def test_widget_data_present_on_init(self):
+            fig = go.FigureWidget(data=go.Bar(x=[1, 2], y=[1, 2]))
+            assert fig._widget_data != []