Add missing private constructors to utilities classes

[jbduncan]

Overview

As requested by @sbrannen in https://github.com/junit-team/junit5/pull/961/files#r134089533, this PR takes a subset of the changes proposed for https://github.com/junit-team/junit5/pull/961/files and makes them a separate PR.

This is just a cleanup PR designed to add missing private constructors to various utilities classes.

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I hereby agree to the terms of the JUnit Contributor License Agreement.

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Definition of Done

• There are no TODOs left in the code
• Method preconditions are checked and documented in the method's Javadoc
• Coding conventions (e.g. for logging) have been followed
• Change is covered by automated tests
• Public API has Javadoc and @API annotations
• All continuous integration builds pass

[jbduncan]

Note for self: Add private constructor for Assumptions as well, as per https://github.com/junit-team/junit5/pull/961/files#r134089666.

[jbduncan]

Further note: Add private constructor for TestRuleAnnotatedMemberFactory as well, as per https://github.com/junit-team/junit5/pull/961/files#r134090410.

[jbduncan]

Also add private constructor for AnnotationConsumerInitializer...

[jbduncan]

Also add for LauncherFactory...

[jbduncan]

Further note: Don't forget to remove all mentioned private constructors from #961.

[marcphilipp]

Would I be interpreting your comments correctly, if I said this PR is not ready to be reviewed, yet?

[jbduncan]

Hi @marcphilipp, yes, that's right, I'm not quite ready for review yet.

I'll post a message along the lines of "Ready for review" when I'm ready. :)

[jbduncan]

Further note: Put all other whitespace and polishing related changes noted in #961 (review) in a new "Polishing" PR.

[jbduncan]

@marcphilipp Ready for review now. :)

[sbrannen]

in progress

[sbrannen]

This has been merged into master.

Thanks

[jbduncan]

Ta @sbrannen! I'll look into creating a new "Polishing" PR in the foreseeable future. :)