diff --git a/test_me_on_student4.py b/test_me_on_student4.py
new file mode 100644
index 0000000000000000000000000000000000000000..751d20e4a1c61631ad6bc6a76350756e77a42b7e
--- /dev/null
+++ b/test_me_on_student4.py
@@ -0,0 +1,49 @@
+import unittest
+from other.student4.Calculator import StringCalculator  # Marvin
+
+class TestMyCasesOnStudent4(unittest.TestCase):
+    def setUp(self):
+        self.calc = StringCalculator()
+
+    def test_empty_string(self):
+        self.assertEqual(self.calc.add(""), 0)
+
+    def test_single_number(self):
+        self.assertEqual(self.calc.add("1"), 1)
+
+    def test_two_numbers(self):
+        self.assertEqual(self.calc.add("1,2"), 3)
+
+    def test_multiple_numbers(self):
+        self.assertEqual(self.calc.add("1,2,3,4,5"), 15)
+
+    def test_numbers_with_newline(self):
+        self.assertEqual(self.calc.add("1\n2,3"), 6)
+
+    def test_multiple_newlines(self):
+        self.assertEqual(self.calc.add("1\n2\n3\n4\n5"), 15)
+
+    def test_negative_number(self):
+        with self.assertRaises(ValueError) as e:
+            self.calc.add("1,-2,3")
+        self.assertEqual(str(e.exception), "Negative numbers are not allowed: -2")
+
+    def test_multiple_negative_numbers(self):
+        with self.assertRaises(ValueError) as e:
+            self.calc.add("1,-2,-3,4")
+        self.assertEqual(str(e.exception), "Negative numbers are not allowed: -2, -3")
+
+    def test_custom_delimiter(self):
+        self.assertEqual(self.calc.add("//;\n1;2"), 3)
+
+    def test_custom_delimiter_with_newline(self):
+        self.assertEqual(self.calc.add("//;\n1;2\n3"), 6)
+
+    def test_ignore_numbers_over_1000(self):
+        self.assertEqual(self.calc.add("2,1001"), 2)
+
+    def test_custom_delimiter_any_length(self):
+        self.assertEqual(self.calc.add("//[***]\n1***2***3"), 6)
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/test_student4_on_me.py b/test_student4_on_me.py
new file mode 100644
index 0000000000000000000000000000000000000000..70cde1ecfb2ff0ffd124b19898249cd1413ed37a
--- /dev/null
+++ b/test_student4_on_me.py
@@ -0,0 +1,55 @@
+import unittest
+from my_string_calculator import StringCalculator 
+
+class TestStudent4CasesOnMe(unittest.TestCase):
+    def setUp(self):
+        self.calculator = StringCalculator()
+
+    def test_empty_string_returns_zero(self):
+        self.assertEqual(self.calculator.add(""), 0)
+
+    def test_single_number_returns_value(self):
+        self.assertEqual(self.calculator.add("1"), 1)
+
+    def test_two_numbers_return_sum(self):
+        self.assertEqual(self.calculator.add("1,2"), 3)
+
+    def test_add_multiple_numbers(self):
+        self.assertEqual(self.calculator.add("1,2,3,4,5"), 15)
+
+    def test_add_numbers_with_newlines(self):
+        self.assertEqual(self.calculator.add("1\n2\n3"), 6)
+
+    def test_add_negative_numbers(self):
+        with self.assertRaises(ValueError) as e:
+            self.calculator.add("-1,2,-3")
+        self.assertEqual(str(e.exception), "Negatives not allowed: -1, -3")
+
+    def test_add_numbers_with_custom_delimiter(self):
+        self.assertEqual(self.calculator.add("//;\n1;2;3"), 6)
+
+    def test_add_numbers_with_custom_delimiter_different_symbol(self):
+        self.assertEqual(self.calculator.add("//#\n4#5#6"), 15)
+
+    def test_custom_delimiter_with_multiple_numbers(self):
+        self.assertEqual(self.calculator.add("//:\n1:2:3:4:5:6"), 21)
+
+    def test_add_numbers_greater_than_1000(self):
+        self.assertEqual(self.calculator.add("1,1001,2,3"), 6)
+
+    def test_add_numbers_with_newlines_and_ignore_above_1000(self):
+        self.assertEqual(self.calculator.add("1\n2\n1000\n1001"), 1003)
+
+    def test_add_numbers_with_custom_delimiter_long_length(self):
+        self.assertEqual(self.calculator.add("//[***]\n1***2***3"), 6)
+
+    def test_custom_long_delimiter_with_large_number_ignored(self):
+        self.assertEqual(self.calculator.add("//[***]\n1***1001***2"), 3)
+
+    def test_custom_long_delimiter_with_negative_numbers(self):
+        with self.assertRaises(ValueError) as e:
+            self.calculator.add("//[***]\n1***-2***3***-4")
+        self.assertEqual(str(e.exception), "Negatives not allowed: -2, -4")
+
+if __name__ == "__main__":
+    unittest.main()