Add InventoryManagementSystem app

InventoryManagementSystem/src/test/java/inventory/DiscountCalculatorTest.java

@@ -0,0 +1,142 @@
+package inventory;
+
+import inventory.DiscountCalculator.DiscountResult;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+import org.junit.jupiter.params.provider.ValueSource;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+
+/**
+ * Unit tests for DiscountCalculator class.
+ */
+class DiscountCalculatorTest {
+
+    private Product book;
+    private Product electronics;
+
+    /**
+     * Set up test data before each test
+     */
+    @BeforeEach
+    void setUp() {
+        book = ProductFactory.createProduct("B001", "Test Book", "BOOK", 20.0, 10);
+        electronics = ProductFactory.createProduct("E001", "Test Electronics", "ELECTRONICS", 100.0, 10);
+    }
+
+    /**
+     * Test student discount on books
+     */
+    @Test
+    void testStudentDiscountOnBooks() {
+        DiscountResult discount = DiscountCalculator.calculateDiscount(book, 1, "STUDENT");
+        assertNotNull(discount);
+        assertEquals(1 * book.getPrice() * 0.10, discount.getDiscountAmount());
+        assertEquals("Student discount: 10% off books", discount.getDescription());
+    }
+
+    /**
+     * Test student discount on electronics (should not apply)
+     */
+    @Test
+    void testStudentDiscountOnElectronics() {
+        DiscountResult discount = DiscountCalculator.calculateDiscount(electronics, 1, "STUDENT");
+        assertNotNull(discount);
+        assertEquals(0, discount.getDiscountAmount());
+        assertEquals("Student discount only applies to books", discount.getDescription());
+    }
+
+    /**
+     * test bulk discount when quantity >= 5
+     */
+    @ParameterizedTest(name = "quantity = {arguments}")
+    @ValueSource(ints = {5,10})
+    void testBulkDiscountValid(int quantity) {
+        DiscountResult discountBook = DiscountCalculator.calculateDiscount(book, quantity, "BULK");
+        assertNotNull(discountBook);
+        assertEquals(quantity * book.getPrice() * 0.15, discountBook.getDiscountAmount());
+        assertEquals("Bulk discount: 15% off for 5+ items", discountBook.getDescription());
+
+        DiscountResult discountElectronics = DiscountCalculator.calculateDiscount(electronics, quantity, "BULK");
+        assertNotNull(discountElectronics);
+        assertEquals(quantity * electronics.getPrice() * 0.15, discountElectronics.getDiscountAmount());
+        assertEquals("Bulk discount: 15% off for 5+ items", discountElectronics.getDescription());
+    }
+
+    /**
+     * Test bulk discount when quantity < 5
+     */
+    @Test
+    void testBulkDiscountInvalid() {
+        DiscountResult discountBook = DiscountCalculator.calculateDiscount(book, 2, "BULK");
+        assertNotNull(discountBook);
+        assertEquals(0, discountBook.getDiscountAmount());
+        assertEquals("Bulk discount requires 5+ items", discountBook.getDescription());
+    }
+
+    /**
+     * Test no discount option
+     */
+    @Test
+    void testNoDiscount() {
+        DiscountResult discountBook = DiscountCalculator.calculateDiscount(book, 1, "NONE");
+        assertNotNull(discountBook);
+        assertEquals(0, discountBook.getDiscountAmount());
+        assertEquals("No discount applied", discountBook.getDescription());
+    }
+
+    /**
+     * Test boundary conditions
+     */
+    @ParameterizedTest(name = "quantity =  {0}, discount(%) = {1}")
+    @CsvSource({"1,0", "5,0.15", "100,0.15", "1000,0.15", "10000,0.15"})
+    void testBoundaryConditions(int quantity, double discountPercentage) {
+        DiscountResult discountBook = DiscountCalculator.calculateDiscount(book, quantity, "BULK");
+        assertNotNull(discountBook);
+        assertEquals(book.getPrice() * quantity * discountPercentage, discountBook.getDiscountAmount());
+    }
+
+    /**
+     * Test discount calculation accuracy
+     */
+    @Test
+    void testDiscountCalculationAccuracy() {
+        DiscountResult discountBook = DiscountCalculator.calculateDiscount(book, 2, "STUDENT");
+        assertNotNull(discountBook);
+        assertEquals(4, discountBook.getDiscountAmount());
+
+        DiscountResult discountElectronics = DiscountCalculator.calculateDiscount(electronics, 5, "BULK");
+        assertNotNull(discountElectronics);
+        assertEquals(75, discountElectronics.getDiscountAmount());
+    }
+
+    @ParameterizedTest(name = "type = {0}")
+    @ValueSource(strings = {"STUDENT", "student", "STUdent", "stuDent", "sTudenT"})
+    void testCaseSensitivityOfDiscountTypes(String type) {
+        DiscountResult discountBook = DiscountCalculator.calculateDiscount(book, 1, type);
+        assertNotNull(discountBook);
+        assertEquals(2, discountBook.getDiscountAmount());
+    }
+
+    @ParameterizedTest(name = "type = {0}")
+    @ValueSource(strings = {"", "--", "\n", "09999", "STUDENT1", "BULKSTUDENT"})
+    void testInvalidDiscountTypes(String type) {
+        DiscountResult discountBook = DiscountCalculator.calculateDiscount(book, 1, type);
+        assertNotNull(discountBook);
+        assertEquals(0, discountBook.getDiscountAmount());
+    }
+
+    @Test
+    void testDiscountZeroQuantity() {
+        DiscountResult discountBook = DiscountCalculator.calculateDiscount(book, 0, "STUDENT");
+        assertNotNull(discountBook);
+        assertEquals(0, discountBook.getDiscountAmount());
+
+        DiscountResult discountElectronics = DiscountCalculator.calculateDiscount(electronics, 0, "BULK");
+        assertNotNull(discountElectronics);
+        assertEquals(0, discountElectronics.getDiscountAmount());
+    }
+}