Fix a bug in the sprites base file and added a basic sprites test case to the compass test.

frameworks/compass/stylesheets/compass/utilities/sprites/_base.scss

@@ -1,3 +1,6 @@
+// Determines those states for which you want to enable magic sprite selectors
+$sprite-selectors: hover, target, active !default;
+
 // Set the width and height of an element to the original
 // dimensions of an image before it was included in the sprite.
 @mixin sprite-dimensions($map, $sprite) {

frameworks/compass/stylesheets/compass/utilities/sprites/_sprite-img.scss

@@ -24,8 +24,6 @@ $sprite-image-default-width: $sprite-default-size !default;
 
 $sprite-image-default-height: $sprite-default-size !default;
 
-$sprite-selectors: hover, target, active !default;
-
 // Sets all the rules for a sprite from a given sprite image to show just one of the sprites.
 // To reduce duplication use a sprite-bg mixin for common properties and a sprite-select mixin for positioning.
 @mixin sprite-img($img, $col, $row: 1, $width: $sprite-image-default-width, $height: $sprite-image-default-height, $margin: $sprite-default-margin) {