diff --git a/app/src/main/java/com/coderabbit/app/calculator/Calculator.kt b/app/src/main/java/com/coderabbit/app/calculator/Calculator.kt
new file mode 100644
index 0000000..13da839
--- /dev/null
+++ b/app/src/main/java/com/coderabbit/app/calculator/Calculator.kt
@@ -0,0 +1,8 @@
+package com.coderabbit.app.calculator
+
+class Calculator {
+
+    fun add(a: Int, b: Int): Int {
+        return a + b
+    }
+}
\ No newline at end of file
diff --git a/app/src/test/java/com/coderabbit/app/calculator/CalculatorTest.kt b/app/src/test/java/com/coderabbit/app/calculator/CalculatorTest.kt
new file mode 100644
index 0000000..0416e1d
--- /dev/null
+++ b/app/src/test/java/com/coderabbit/app/calculator/CalculatorTest.kt
@@ -0,0 +1,13 @@
+package com.coderabbit.app.calculator
+
+import org.junit.Assert.assertTrue
+import org.junit.Test
+
+class CalculatorTest {
+
+    @Test
+    fun `test add function`() {
+        val calculator = Calculator()
+        assertTrue(calculator.add(1,2) == 3)
+    }
+}
\ No newline at end of file