在IntelliJ IDEA中，测试如何访问正在测试的代码的PSI树结构？

Question

Running tests from the IntelliJ IDEA IDE, I want them to be able to do some custom static analysis on the code being tested. To that end, I want the tests to be able to access the PSI tree structure of the tested code. Is this possible? How?

Here it is an example of the usefulness of this: In Hibernate, final methods of entity classes should not directly access any fields. So, I would like to write a test that checks that all classes annotated with @Entity have no final methods that reference fields. This I can't do with reflection. I need access to the PSI tree. This is just an example, and there are many more use cases for such capabilities.

I know this couples tests to IntelliJ IDEA. And I know I could write an IntelliJ IDEA plugin to implement "inspections" to do this kind of analysis. But I want to write this as tests. Tests that can be red or green. Tests that could emit meaningful error messages. Tests that could run the code, access the code through reflection, and also access the PSI tree.

Answer 1

What you are trying to do is basically to work on the AST outputted by a parser, so one way to do it is to write unit tests that extend ParsingTestCase . The initial behavior of those kind of tests is to print a readable version of the AST and compare it with an expected file, but you can override a method to do completely different tests, while keeping the easy way to retrieve a PSI tree:

import com.intellij.testFramework.ParsingTestCase;

public class MyAwesomeTest extends ParsingTestCase {

    public MyAwesomeTest() {
        super("relative/path/to/files", "java", new JavaParserDefinition());
    }

    @Override
    protected boolean skipSpaces() {
        return true;
    }

    public void testEmpty() {
        doTest(true); // this will test relative/path/to/files/Empty.java
    }

    @Override
    protected void checkResult(@NonNls @TestDataFile String targetDataName, final PsiFile file) throws IOException {
        // do your stuff here
    }

}

Note that file names are extracted from test method names (here, Empty ), which can be annoying if you want to test lots of files, especially when their name is only known at runtime. To overcome this, you can replace doTest() with a custom method that does similar things with an additional name argument.

Then to run those tests, you'll have to download IntelliJ (either Ultimate or Community) and add a bunch of Jar files located in Intellij/lib/ to your classpath. Otherwise, it might be possible to run unit tests in IntelliJ's headless mode, but I don't know how.

Additional info here: https://confluence.jetbrains.com/display/IDEADEV/Testing+IntelliJ+IDEA+Plugins