Handle cryptic error message being thrown

[jamesgeorge007]

misconfigured config file

Fixes #9295

What kind of change does this PR introduce?
refactoring

Did you add tests for your changes?
N/A

Does this PR introduce a breaking change?
Nope

What needs to be documented once your changes are merged?
Nil

[webpack-bot]

For maintainers only:

• This need to be documented (issue in webpack/webpack.js.org will be filed when merged)

[webpack-bot]

Thank you for your pull request! The most important CI builds succeeded, we’ll review the pull request soon.

[sokra]

Add a test cases

test/Validation.test.js seems like a good place

[jamesgeorge007]

@sokra I'm not that familiar with the code-base. Can you throw light on how it should be regarding writing the test case 🤔

[sokra]

Run yarn setup first.

Then you should be able to run the Validation tests with yarn jest Validation --watch -u. The -u updates the snapshots automatically.

Copy one of the tests in the file and create a invalid config like in the issue. Running the test will update the snapshot to the expected error message.

[sokra]

see 226e8ce

[jamesgeorge007]

So are we all set to go ahead?

[sokra]

Yep, thanks