Add expr active item test

src/test/skript/tests/syntaxes/expressions/ExprActiveItem.sk

@@ -0,0 +1,19 @@
+test "Active Item Expression":
+	spawn a cow at test-location:
+		set {_cow} to entity
+	assert active item of {_cow} is not set with "A cow that is not using an item should have no active item"
+	clear entity within {_cow}
+
+test "Active Item Plurality":
+	spawn 2 cows at test-location:
+		add entity to {_cows::*}
+	assert active item of {_cows::*} is not set with "A list of idle entities should return no active items"
+	clear entities within {_cows::*}
+
+test "Active Item Aliases":
+	spawn a cow at test-location:
+		set {_cow} to entity
+	assert raised tool of {_cow} is not set with "'raised tool' alias should work"
+	assert active weapon of {_cow} is not set with "'active weapon' alias should work"
+	assert {_cow}'s active item is not set with "Possessive syntax should work"
+	clear entity within {_cow}