add another low bitdepth png save test

2022-08-14 11:05:09 +01:00 · 2022-08-14 11:05:09 +01:00 · 94d3f93a46
commit 94d3f93a46
parent ca2796aa7f
1 changed files with 6 additions and 0 deletions
--- a/test/test-suite/test_foreign.py
+++ b/test/test-suite/test_foreign.py
@ -410,6 +410,12 @@ class TestForeign:
        len_mono1 = len(self.mono.write_to_buffer(".png", bitdepth=1))
        assert( len_mono1 < len_mono2 )

+        # take a 1-bit image to png and back
+        onebit = self.mono > 128
+        data = onebit.write_to_buffer(".png", bitdepth=1)
+        after = pyvips.Image.new_from_buffer(data, "")
+        assert( (onebit - after).abs().max() == 0 )
+
        # we can't test palette save since we can't be sure libimagequant is
        # available and there's no easy test for its presence