Class<Test> object not the same type as a Test object? Junit

I'm trying to write some code which recursively adds TestSuites in a project to a suite of suites located at the root of the package hierarcy.

I've already written the code which returns a Collection object which contains a File object for each Test Suite found in my project.

I'm now trying to loop through them and add them to a TestSuite in a file called AllTests.java:

public static Test suite() throws IOException, ClassNotFoundException {
    TestSuite suite = new TestSuite();

            //Code not included for getTestSuites() in this snippet.
    Collection<File> testSuites = getTestSuites();
    for(File f: testSuites) {

            //Truncate the path of the test to the beginning of the package name
            String testName = f.getAbsolutePath().substring(f.getAbsolutePath().lastIndexOf("net"));

            //Replace backslashes with fullstops
            testName = te开发者_如何学CstName.replaceAll("\\\\", ".");

            //Take the .class reference off the end of the path to the class
            testName = testName.replaceAll(".class", "");

            //Add TestSuite to Suite of Suites

            Class<? extends Test> test = (Class<? extends Test>) AllTests.class.getClassLoader().loadClass(testName);
            suite.addTest(test);
    }

Unfortunately I am getting the following compiler error on the suite.addTest(test) line:

The method addTest(Test) in the type TestSuite is not applicable for the arguments (Class < capture#3-of ? extends Test>)

Am I making a fundamental mistake by assuming that a Class< Test > reference and a Test reference are one and the same?

---

Yes, you are making a fundamental mistake by assuming that a Class< Test > reference and a Test reference are one and the same.

You need an instance of a Class that extends Test, not an instance of a Class object whose definition extends Test (Classes are objects too in java).

---

TestSuite.addTest needs a Test class instance; not just a Class object.

You could try using Class.newInstance() if your tests can be (they should) instantiated without parameters.

--

A maybe better strategy is to start using Maven; which automatically runs all Test classes in the src/test/java source folder. But that can be a quite big overhaul :).

---

Class<Test> describes the concept of class Test -- its fields, methods, and other stuff described by the Java code when defining class Test. There is generally (to keep classloaders out of this discussion) one instance of Class<Test> across the JVM, since there is basically just one Test class.

The same applies for every Test subclass -- there is generally one instance of Class<TestSubClass> for every TestSubClass.

On the other hand, there can be any number of Test objects.

Java allows you to create Test objects from a Class<Test>, by invoking newInstance against your Class<Test> instance. So basically, change your line from:

suite.addTest(test);

to

suite.addTest(test.newInstance());

And handle all potential exceptions.

---

Method you are using expects instance of Test (sub)class. The one you are after is probably addTestSuite(Class testClass) which allows adding classes.