[BAEL-9326] unit tests

Author: venkat1701

spring-ai-modules/spring-ai-mcp/mcp-spring/mcp-server-oauth2/src/test/java/com/baeldung/mcp/mcpserveroauth2/CalculatorServiceTest.java

@@ -0,0 +1,66 @@
+package com.baeldung.mcp.mcpserveroauth2;
+
+import com.baeldung.mcp.mcpserveroauth2.model.CalculationResult;
+import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.*;
+
+class CalculatorServiceTest {
+    private final CalculatorService calculatorService = new CalculatorService();
+
+    @Test
+    void givenTwoNumbers_whenAdd_thenReturnsSum() {
+        CalculationResult result = calculatorService.add(5.0, 3.0);
+        assertEquals("addition", result.operation());
+        assertEquals(5.0, result.operand1());
+        assertEquals(3.0, result.operand2());
+        assertEquals(8.0, result.result());
+    }
+
+    @Test
+    void givenTwoNumbers_whenSubtract_thenReturnsDifference() {
+        CalculationResult result = calculatorService.subtract(10.0, 4.0);
+        assertEquals("subtraction", result.operation());
+        assertEquals(10.0, result.operand1());
+        assertEquals(4.0, result.operand2());
+        assertEquals(6.0, result.result());
+    }
+
+    @Test
+    void givenTwoNumbers_whenMultiply_thenReturnsProduct() {
+        CalculationResult result = calculatorService.multiply(6.0, 7.0);
+        assertEquals("multiplication", result.operation());
+        assertEquals(6.0, result.operand1());
+        assertEquals(7.0, result.operand2());
+        assertEquals(42.0, result.result());
+    }
+
+    @Test
+    void givenTwoNumbers_whenDivide_thenReturnsQuotient() {
+        CalculationResult result = calculatorService.divide(15.0, 3.0);
+        assertEquals("division", result.operation());
+        assertEquals(15.0, result.operand1());
+        assertEquals(3.0, result.operand2());
+        assertEquals(5.0, result.result());
+    }
+
+    @Test
+    void givenZeroDivisor_whenDivide_thenThrowsException() {
+        IllegalArgumentException ex = assertThrows(IllegalArgumentException.class, () ->
+            calculatorService.divide(10.0, 0.0)
+        );
+        assertEquals("Cannot divide by zero", ex.getMessage());
+    }
+
+    @Test
+    void givenNegativeNumbers_whenAdd_thenReturnsSum() {
+        CalculationResult result = calculatorService.add(-2.0, -3.0);
+        assertEquals(-5.0, result.result());
+    }
+
+    @Test
+    void givenLargeNumbers_whenMultiply_thenReturnsProduct() {
+        CalculationResult result = calculatorService.multiply(1e6, 1e6);
+        assertEquals(1e12, result.result());
+    }
+}
+