Add addition_isNotEqual test

Author: parkcheayeon

feature/stoplist/src/test/java/com/chaeny/busoda/stoplist/ExampleUnitTest.kt

@@ -14,4 +14,9 @@ class ExampleUnitTest {
     fun addition_isCorrect() {
         assertEquals(4, 2 + 2)
     }
-}
+
+    @Test
+    fun addition_isNotEqual() {
+        assertNotEquals(5, 2 + 2)
+    }
+}