diff --git a/parser/lexer_test.go b/parser/lexer_test.go
index faa98a48..7e1e5faf 100644
--- a/parser/lexer_test.go
+++ b/parser/lexer_test.go
@@ -351,6 +351,21 @@ Second line \
 			token.RIGHT_BRACKET, "", 6,
 		)
 
+		// Identifier from Unicode Nl
+		test("\u16ee",
+			token.IDENTIFIER, "ᛮ", 1,
+		)
+
+		// Identifier from Unicode Other_ID_Start
+		test("\u212e",
+			token.IDENTIFIER, "℮", 1,
+		)
+
+		// Using char from ID_Continue after valid start char
+		test("a\u0300",
+			token.IDENTIFIER, "à", 1,
+		)
+
 		// ILLEGAL
 
 		test(`3ea`,
@@ -383,5 +398,15 @@ Second line \
 			token.STRING, "\"\\x0G\"", 1,
 			token.EOF, "", 7,
 		)
+
+		// Starting identifier with ID_Continue char from Nm
+		test("\u0300",
+			token.ILLEGAL,
+		)
+
+		// Starting identifier with Pattern_Syntax
+		test("'",
+			token.ILLEGAL,
+		)
 	})
 }