Add test that exposes race condition

test/non_thread_safe_integer_test.rb

@@ -0,0 +1,42 @@
+# frozen_string_literal: true
+
+require "test_helper"
+
+class TestNonThreadSafeInteger < Minitest::Test
+  def setup
+    @integer = ::Semian::Simple::Integer.new # Using non-thread-safe implementation
+  end
+
+  def teardown
+    @integer.destroy
+  end
+
+  # The concurrent test that should expose race conditions
+  # Race condition:
+  # Thread A calls increment(1)
+  # Thread B calls @atom.value = 0
+  # Thread A's increment can complete after the assignment, overwriting the reset
+  def test_concurrent_reset
+    threads = []
+
+    assert_equal(0, @integer.value, "Integer should be initialized to 0")
+
+    4.times do
+      threads << Thread.new do
+        10.times { @integer.increment(1) }
+      end
+    end
+
+    threads << Thread.new do
+      @integer.reset
+    end
+
+    threads.each(&:join)
+
+    assert_equal(0, @integer.value, "Integer should be 0 after reset")
+
+    @integer.increment(5)
+
+    assert_equal(5, @integer.value, "Integer should work normally after reset")
+  end
+end