images.gif: added unit tests

extra/images/gif/gif-tests.factor

@@ -0,0 +1,29 @@
+! Copyright (C) 2009 Keith Lazuka.
+! See http://factorcode.org/license.txt for BSD license.
+USING: accessors images.gif io io.encodings.binary io.files
+math namespaces sequences tools.test math.bitwise ;
+IN: images.gif.tests
+
+: path>gif ( path -- loading-gif )
+    binary [ input-stream get load-gif ] with-file-reader ;
+
+: gif-example1 ( -- loading-gif )
+    "resource:extra/images/testing/symbol-word-16-colors.gif" path>gif ;
+
+: gif-example2 ( -- loading-gif )
+    "resource:extra/images/testing/check-256-colors.gif" path>gif ;
+
+: gif-example3 ( -- loading-gif )
+    "resource:extra/images/testing/monochrome.gif" path>gif ;
+
+: declared-num-colors ( gif -- n ) flags>> 3 bits 1 + 2^ ;
+: actual-num-colors ( gif -- n ) global-color-table>> length 3 /i ;
+
+[ 16 ] [ gif-example1 actual-num-colors ] unit-test
+[ 16 ] [ gif-example1 declared-num-colors ] unit-test
+
+[ 256 ] [ gif-example2 actual-num-colors ] unit-test
+[ 256 ] [ gif-example2 declared-num-colors ] unit-test
+
+[ 2 ] [ gif-example3 actual-num-colors ] unit-test
+[ 2 ] [ gif-example3 declared-num-colors ] unit-test