added test

src/napari_matplotlib/tests/test_feature_histogram.py

@@ -0,0 +1,22 @@
+from napari_matplotlib import FeatureHistogramWidget
+import numpy as np
+
+def test_example_q_widget(make_napari_viewer):
+    # Smoke test adding a histogram widget
+    viewer = make_napari_viewer()
+
+    image = np.asarray([[0, 1], [2, 1]])
+    labels = image.astype(int)
+
+
+    viewer.add_image(image)
+
+    labels_layer = viewer.add_labels(labels)
+
+    labels_layer.features = {
+        'labels': [1, 2],
+        'area': [2, 1],
+        'aspect_ratio': [2, 1]
+    }
+
+    FeatureHistogramWidget(viewer)