add expr length tests

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

@@ -0,0 +1,34 @@
+test "basic string length":
+	assert length of "hello" is 5 with "Length of a simple string literal should be correct"
+
+	set {_string} to "Skript"
+	assert length of {_string} is 6 with "Length of a string variable should be correct"
+
+test "edge case string lengths":
+	set {_empty_string} to ""
+	assert length of {_empty_string} is 0 with "Length of an empty string should be 0"
+
+	assert length of "   " is 3 with "Length of a string with only whitespace should be correct"
+	assert length of "😂" is 2 with "Length of a Unicode emoji should be calculated correctly"
+
+test "type conversion for length":
+	assert length of "12345" is 5 with "Length of a numeric string should be correct"
+
+	clear {_undefined}
+	assert length of {_undefined} is not set with "Length of an undefined variable should be unset"
+
+test "list looping behavior of length":
+	set {_list::*} to "a", "bb", and "cherry"
+	set {_lengths::*} to length of {_list::*}
+
+	assert {_lengths::1} is 1 with "First element of looped lengths should be correct"
+	assert {_lengths::2} is 2 with "Second element of looped lengths should be correct"
+	assert {_lengths::3} is 6 with "Third element of looped lengths should be correct"
+
+test "string interpolation":
+	set {_string} to "Skript"
+	set {_empty_string} to ""
+
+	assert "%length of "hello"%" is "5" with "String interpolation with a literal should work"
+	assert "%length of {_string}%" is "6" with "String interpolation with a variable should work"
+	assert "%length of {_empty_string}%" is "0" with "String interpolation with an empty string should work"