Fix string test

tests/test_strings.py

@@ -1,6 +1,7 @@
 # pylint: disable=missing-class-docstring,no-self-use
 from __future__ import annotations
 
+import re
 import unittest
 
 import claripy
@@ -12,6 +13,19 @@ class TestStrings(unittest.TestCase):
     def get_solver(self):
         return claripy.SolverStrings(backend=claripy.backends.z3)
 
+    def replace_unicode(self, match):
+        """
+        Converts a Unicode escape sequence to the corresponding character.
+
+        Args:
+        - match (re.Match): A regex match object containing a Unicode escape sequence.
+
+        Returns:
+        - str: The Unicode character corresponding to the hexadecimal code.
+        """
+        hex_code = match.group(1)
+        return chr(int(hex_code, 16))
+
     def test_concat(self):
         str_concrete = claripy.StringV("conc")
         str_symbol = claripy.StringS("symb_concat", 4, explicit_name=True)
@@ -268,7 +282,6 @@ def test_index_of_simplification(self):
         self.assertEqual((), tuple(solver.constraints))
         self.assertEqual((target_idx,), solver.eval(res, 2))
 
-    @unittest.skip("Usually hangs")
     def test_index_of_symbolic_start_idx(self):
         str_symb = claripy.StringS("symb_index_of", 4, explicit_name=True)
         start_idx = claripy.BVS("symb_start_idx", 32, explicit_name=True)
@@ -281,12 +294,14 @@ def test_index_of_symbolic_start_idx(self):
 
         solver.add(res != -1)
         solver.add(res < 38)
+
         self.assertTrue(solver.satisfiable())
-        self.assertEqual({33, 34, 35, 36, 37}, set(solver.eval(res, 10)))
+        self.assertEqual({33, 34, 35, 36, 37}, set(solver.eval(res, 5)))
 
         strs = solver.eval(str_symb, 10 if KEEP_TEST_PERFORMANT else 100)
         for s in strs:
-            self.assertTrue(32 < s.index("an") < 38)
+            converted_string = re.sub(r"\\u\{([0-9a-fA-F]+)\}", self.replace_unicode, s)
+            self.assertTrue(32 < converted_string.index("an") < 38)
 
     def test_str_to_int(self):
         str_symb = claripy.StringS("symb_strtoint", 4, explicit_name=True)