JUnit测试可以从返回断言的对象中解析吗？

Question

Can a JUnit test resolve from a object returning a Assertion?

For example, if I have a test that looks like this, would this work?

@Test
public void testCase1() {
    TestObject to = new TestObject();
    to.login();
    to.runTest();
    // then assert success
    to.verifyTest();

}

public Class TestObject() {
  ....
  public Assert verifyTest() {
    return assertTrue("Test result not found.", this.validateTestResult() );
  }
}

Answer 1

Most Assert calls throw an AssertionError if they fail, so the code wouldn't look exactly the way you put it, but your code could be adjusted slightly and compile/run. Because they are implemented as exceptions, you can call Assert methods from anywhere, including any helper classes you set up to help run your tests easier, as far deep in the stack as you'd like.

EDIT : I do very much recommend setting up helper classes if you need to make a similar set of assertions against many objects. I misunderstood and thought your TestObject was your system under test; the rest applies to that situation instead.

==

There's nothing to prevent you from calling Assert methods from within the class under test, but part of the intention for JUnit is to have clean test classes that are separate from your code classes. That way, the tests can evolve separately and often do not even need to change unless your class's interface changes. In my code, I put them in the same package in a separate "source folder", so you have:

• src/com/mypackage/project1/database/DatabaseAccessor.java
• testsrc/com/mypackage/project1/database/DatabaseAccessorTest.java
• testsrc/com/mypackage/project1/database/DatabaseAccessorSystemTest.java

One of the reasons to separate things this way is to ensure that no testing code is ever run in production; if the verifyTest method is in the same class, there's nothing to stop you from calling it within your class--or worse, from other classes calling it from elsewhere in your codebase. You also avoid depending on junit.jar from production code.

If you are looking to make assertions in production code to avoid inconsistent state or illegal arguments, that's a different matter, and one for which you should avoid JUnit's Assert class--or, for that matter, assert statements (which are compiled out based on arguments to javac ). Instead, prefer a library like Guava's Preconditions .