java - 如何为内部包含 "this"的方法编写Junit测试

Question

我有以下方法:

public class Store {

   @Autowired 
   private List<Products> products;

   public Products find(final String id) {
        for (final Products product : this.products) {
            if (product.getId().equalsIgnoreCase(id)) {
                return product;
            }
        }
        return null;
    }
}

如何为这个方法编写Junit？如果我这样写，就会发生 NullPointerException。

@SpringBootTest
@ContextConfiguration(locations = {"classpath*:beans.xml"})
@RunWith(SpringRunner.class)
public class StoreTest {

    @SuppressWarnings("unused")
    @Autowired
    private List<Products> products;

    @Test
    public void find() {
        Store store = new Store();
        Products product = new Products();
        product = store.find("1");
        final String result = product.getName();
        Assert.assertEquals("it should be equal", "Milk", result);
    }

}

提前致谢!

Answer 1

您没有将产品对象或产品列表添加到商店中，因此 find 返回 null 是有意义的。

您可以做的是将产品添加到商店，然后检查产​​品的结果是否为空，如果是则断言出了问题。您还可以检查您添加的产品是否是您正在查找的产品。

@Test
public void find() {
    final Store store = new Store();

    final List<Products> products = new ArrayList<>();

    final Products product1 = new Products("Cucumber", "The best cucmber", 500, "1");
    final Products product2 = new Products("Cherry", "The best Cherry", 1000, "2");
    Products product = new Products();

    products.add(product1);
    products.add(product2);

    Products found = store.find("1");

    Assert.assertNotNull(product); // check if result is null

    Assert.assertEquals(product, found); // check if what you added is your result
}