diff --git a/tests/graphics/colour.cpp b/tests/graphics/colour.cpp
index 40b92bbd63..b7df2cc527 100644
--- a/tests/graphics/colour.cpp
+++ b/tests/graphics/colour.cpp
@@ -99,8 +99,11 @@ void ColourTestCase::GetSetRGB()
 void ColourTestCase::FromString()
 {
     ASSERT_EQUAL_RGB( wxColour("rgb(11, 22, 33)"), 11, 22, 33 );
+    // wxX11 doesn't support alpha at all currently.
+#ifndef __WXX11__
     ASSERT_EQUAL_RGBA( wxColour("rgba(11, 22, 33, 0.5)"), 11, 22, 33, 128 );
     ASSERT_EQUAL_RGBA( wxColour("rgba( 11, 22, 33, 0.5 )"), 11, 22, 33, 128 );
+#endif // __WXX11__
 
     ASSERT_EQUAL_RGB( wxColour("#aabbcc"), 0xaa, 0xbb, 0xcc );