java - 静态成员值将被带入下一次测试

Question

我正在对如下所示的类进行单元测试

public class A {
 private static String aStr = null;

 public void doSomething() {
    if (null == aStr) {
       // do something to init aStr, and this initialized val gets cached for future calls.
       aStr = some_val;
    } else {
      // do something else using aStr value.
   }
 }

现在我正在做单元测试:

public class ATest {
 private A a;

 @BeforeMethod
 public void setup() {
    a = new A();
 }

  @Test
  public void test1() {
    a.doSomething();
    // assert on some_val being fetched correctly.
  }

  @Test
  public void test2() {
    a.doSomething();
    // assert again for some_val

    // this is where some_val fetching is not invoked at all, while debugging I 
    // can see that aStr is already being initialized from previous test. 
  }
}

我假设由于我在 @BeforeMethod 设置中重新初始化对象“a”，所以我应该为所有测试获得空值。这个假设不是正确的吗？

Answer 1

java中字段上的

static修饰符意味着该字段不属于该类的特定实例，而是属于类本身。在大多数情况下，您在运行的 JVM 中只有类的示例。因此，您创建该类的多少个对象并不重要 - 它们都将共享一个相同的静态字段。并且该字段的值相同