diff --git a/String/2124. Check if All A's Appears Before All B's.py b/String/2124. Check if All A's Appears Before All B's.py
deleted file mode 100644
index a38714c..0000000
--- a/String/2124. Check if All A's Appears Before All B's.py	
+++ /dev/null
@@ -1,10 +0,0 @@
-class Solution:
-    def checkString(self, s: str) -> bool:
-        b_appear = False
-        for c in s:
-            if c == 'b':
-                b_appear = True
-            else:
-                if b_appear:
-                    return False
-        return True
diff --git a/problems/easy/check_if_all_a_s_appears_before_all_b_s_2124/__init__.py b/problems/easy/check_if_all_a_s_appears_before_all_b_s_2124/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/problems/easy/check_if_all_a_s_appears_before_all_b_s_2124/solution.py b/problems/easy/check_if_all_a_s_appears_before_all_b_s_2124/solution.py
new file mode 100644
index 0000000..82c89be
--- /dev/null
+++ b/problems/easy/check_if_all_a_s_appears_before_all_b_s_2124/solution.py
@@ -0,0 +1,17 @@
+# Tags: String
+class Solution:
+    def check_string(self, s: str) -> bool:
+        """
+        Time Complexity: O(n) where n is the length of string s
+                         - We iterate through the string exactly once
+        Space Complexity: O(1)
+                          - Only a single boolean variable is used
+        """
+        is_b_appear = False
+        for c in s:
+            if c == 'b':
+                is_b_appear = True
+            else:
+                if is_b_appear:
+                    return False
+        return True
diff --git a/problems/easy/check_if_all_a_s_appears_before_all_b_s_2124/test_solution.py b/problems/easy/check_if_all_a_s_appears_before_all_b_s_2124/test_solution.py
new file mode 100644
index 0000000..2014207
--- /dev/null
+++ b/problems/easy/check_if_all_a_s_appears_before_all_b_s_2124/test_solution.py
@@ -0,0 +1,15 @@
+import pytest
+from tests.base_test import BaseTestSolution
+from .solution import Solution
+
+
+class TestSolution(BaseTestSolution):
+    solution = Solution()
+
+    @pytest.mark.parametrize("method_name, s, expected, timeout", [
+        ('check_string', "aaabbb", True, None),
+        ('check_string', "abab", False, None),
+        ('check_string', "bbb", True, None),
+    ])
+    def test_check_string(self, method_name, s, expected, timeout):
+        self._run_test(self.solution, method_name, (s,), expected, timeout)