Improve test coverage

[centic9]

A few test-adjustments:

• Enable one test which was disabled some time ago, but should work again now
• Make sure the local is always "US" to not fail tests when run on systems which have set a different locale
• Cover a few more lines/branches in some tests to slightly increase coverage
• mark tests of deprecated methods with @deprecate to reduce warnings in the IDE

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[garydgregory]

@centic9
Thank you for your PR. I can see that this improves the coverage in all except one case.
Please address all of my comments, and I will get this merged.

[garydgregory]

Why is this important for this test?

That's not how you set with Locale's anyway, this component depends on JUnit Pioneer for this type of stuff (see @DefaultLocale)

I think you can remove this test as this class is already at 100% coverage:

[centic9]

The test fails for me locally when the OS is set to "de" instead of "us".

I don't see @DefaultLocale anywhere, do you have a link?

Anyway, reverted for now as it actually does not increase coverage, but just fixes a local test failure for me.

[garydgregory]

See https://junit-pioneer.org/docs/default-locale-timezone/

[garydgregory]

@centic9
Thank you for your updates.

[garydgregory]

Thank you @centic9
After this PR, I was able to raise the bar on our coverage checks to:

    <commons.jacoco.haltOnFailure>true</commons.jacoco.haltOnFailure>
    <commons.jacoco.classRatio>1.00</commons.jacoco.classRatio>
    <commons.jacoco.instructionRatio>0.99</commons.jacoco.instructionRatio>
    <commons.jacoco.methodRatio>0.99</commons.jacoco.methodRatio>
    <commons.jacoco.branchRatio>0.95</commons.jacoco.branchRatio>
    <commons.jacoco.lineRatio>0.99</commons.jacoco.lineRatio>    
    <commons.jacoco.complexityRatio>0.97</commons.jacoco.complexityRatio>