diff --git a/lib/matplotlib/tests/baseline_images/test_colorbar/colorbar_extend_alpha.png b/lib/matplotlib/tests/baseline_images/test_colorbar/colorbar_extend_alpha.png
diff --git a/lib/matplotlib/tests/test_colorbar.py b/lib/matplotlib/tests/test_colorbar.py
@@ -1124,6 +1124,14 @@ def test_colorbar_set_formatter_locator():
     assert cb.ax.yaxis.get_minor_formatter() is fmt
 
 
+@image_comparison(['colorbar_extend_alpha.png'], remove_text=True,
+                  savefig_kwarg={'dpi': 40})
+def test_colorbar_extend_alpha():
+    fig, ax = plt.subplots()
+    im = ax.imshow([[0, 1], [2, 3]], alpha=0.3, interpolation="none")
+    fig.colorbar(im, extend='both', boundaries=[0.5, 1.5, 2.5])
+
+
 def test_offset_text_loc():
     plt.style.use('mpl20')
     fig, ax = plt.subplots()