Fix fullName use case

[Vanuan]

Fix for some concerns raised in #2

[Vanuan]

With this change and the following test case:

// test1.js
describe('test1', () => {
  it('is a duplicate test', () => {});
});

// test1-2.js
describe('test1', () => {
  it('is a duplicate test', () => {});
});

// test1-3.js
describe('test1', () => {
  it('is a unique test', () => {});
});

// test4.js
describe('test4', => {
  it('is a unique test', () => {})
})

// test5.js
describe('test5', () => {
  it('is a unique test', () => {})
})

I see only one duplicate test (which is a correct behavior but doesn't suit my use case)

Duplicate test names found:
File:  /__tests__/test/test1-2.js
Title:  test1 is a duplicate test

[Vanuan]

Well, actually, I thought it should show me both tests with a duplicate name, shouldn't it?

[palmerj3]

@Vanuan with a little modification it definitely could. I can take a look tomorrow morning and add that. But thank you SO MUCH for this PR and the conversation.

Sorry earlier for the confusion. I really do appreciate the contribution. Is this project something you'd want to collaborate on?

[palmerj3]

I published 1.1.0 with this

[Vanuan]

Well, I'm currently investigating flaky tests in my company's project.
One of the issues I found was copy pasted code (not changing test names when reusing code).
I'm also using jasmineReporters.JUnitXmlReporter to generate xml files which are parsed by Jenkins.
So when one test has failed the build became flaky: depending on whether the passing or the failing test was run last the test result was either fail or pass.

So I found two options:

1. Generating a unique filename using modifyReportFileName callback. It deemed impossible until I found something that you've done here: Add testPath to jest-jasmine2 reporter callbacks jestjs/jest#4594
2. Detecting unique filenames separately. This project doesn't help this use case so much as fullName here and fullName in modifyReportFileName are different for some reason. Probably jest groups fullName by a test filename so it must use the top-level describe for it.

[palmerj3]

Awesome! I work on very similar things at my company.

I wrote this for when we needed junit xml files for the same purpose. You might give it a shot. https://github.com/palmerj3/jest-junit

[palmerj3]

And if you'd like to collaborate on this project or another project (for a better solution) I'd love to do that.