Removed assertion from test case due to platform-specific behaviour. Changed warning to only emit on downcast from float96 or float128. Simplified condition

br-Zhang · br-Zhang · commit 815d10a80d20 · 2018-03-14T11:44:05.000-04:00
diff --git a/lib/matplotlib/image.py b/lib/matplotlib/image.py
@@ -363,14 +363,11 @@ def _make_image(self, A, in_bbox, out_bbox, clip_bbox, magnification=1.0,
                 if inp_dtype.kind == 'f':
                     scaled_dtype = A.dtype
                     # Cast to float64
-                    if (A.dtype == np.longdouble
-                        or (not (A.dtype == np.float64
-                                 or A.dtype == np.float32
-                                 or A.dtype == np.float16))):
+                    if not (A.dtype == np.float32 or A.dtype == np.float16):
                         if (A.dtype != np.float64):
                             warnings.warn(
-                                'Casting input data to float64 for imshow.'
-                            )
+                                "Casting input data from '{0}' to 'float64'"
+                                "for imshow".format(A.dtype))
                         scaled_dtype = np.float64
                 else:
                     # probably an integer of some type.
diff --git a/lib/matplotlib/tests/test_image.py b/lib/matplotlib/tests/test_image.py
@@ -903,12 +903,8 @@ def test_empty_imshow(make_norm):
 def test_imshow_float128():
     fig, ax = plt.subplots()
     ax.imshow(np.zeros((3, 3), dtype=np.longdouble))
-    # Ensure that drawing doesn't cause crash and warning message
-    with warnings.catch_warnings(record=True) as warns:
-        warnings.simplefilter("always")
-        fig.canvas.draw()
-        assert len(warns) == 1
-        assert "Casting input data to float64 for imshow." in str(warns[-1].message)
+    # Ensure that drawing doesn't cause crash
+    fig.canvas.draw()
 
 
 def test_imshow_bool():
