QuarkusUnitTest should support testing startup exceptions due to runtime properties

[Christopher-Chianelli]

Description

= Quarkus Extension test failure at startup

Currently Quarkus supports testing exceptions at

• Build time
• After startup

However, testing exceptions during startup is unsupported.
Exceptions at startup can occur because of a runtime property
that is incompatiable with other runtime properties. For
example, having a password without a username.

If you use QuarkusUnitTest.assertException, you get
AssertionFailedError: The build was expected to fail.

If you try to test the failure without QuarkusUnitTest.assertException,
you get TestInstantiationException: Failed to create test instance
with the runtime exception as the root cause.

This makes it impossible to test startup failures due to runtime config
properties, as there is nowhere to hook the exception assertion code.

Reproducer: https://github.com/Christopher-Chianelli/issue-reproducer/tree/quarkus-unit-test-startup-exception

Implementation ideas

• Add a new method assertStartupException to QuarkusUnitTest
• Modify assertException in QuarkusUnitTest to also test for startup exceptions