Shorten up the code and do event cleanup on test cases.

src/event.js

@@ -1027,16 +1027,11 @@ jQuery.each(["live", "die"], function( i, name ) {
 			return this;
 		}
 
-		if ( jQuery.isFunction( data ) || data === false ) {
-			fn = data;
+		if ( data === false || jQuery.isFunction( data ) ) {
+			fn = data || returnFalse;
 			data = undefined;
 		}	
 
-		if ( fn === false ) {
-			fn = returnFalse;
-		}
-				
-
 		types = (types || "").split(" ");
 
 		while ( (type = types[ i++ ]) != null ) {

test/unit/event.js

@@ -567,6 +567,7 @@ test("live(name, false), die(name, false)", function() {
 	jQuery("#ap").die("click", false);
 	jQuery("#ap").trigger("click");
 	equals( main, 1, "Verify that the trigger happened correctly." );
+	jQuery("#main").die("click");
 });
 
 test("delegate(selector, name, false), undelegate(selector, name, false)", function() {
@@ -587,6 +588,7 @@ test("delegate(selector, name, false), undelegate(selector, name, false)", funct
 	jQuery("#ap").undelegate("#groups", "click", false);
 	jQuery("#groups").trigger("click");
 	equals( main, 1, "Verify that the trigger happened correctly." );
+	jQuery("#main").undelegate("#ap", "click");
 });
 
 test("bind()/trigger()/unbind() on plain object", function() {