Actual problems with these methods:

• Hiding class names in strings and relying on PHP's dark magic to turn strings into objects makes it hard to find usages of these classes.
• Abstract base classes for tests are considered evil. These patches are a step towards getting rid of the abstract base classes.
• It's just not necessary. Just override the getInstance method. Done. This is sooo much simpler.

SerializerBaseTest::getClass patches:

• https://gerrit.wikimedia.org/r/#/c/195295/ (merged)
• https://gerrit.wikimedia.org/r/#/c/195558/ (merged)

ValueFormatterTestBase::getFormatterClass base patch:

• Base: https://github.com/DataValues/Interfaces/pull/9 (merged) and https://github.com/DataValues/Interfaces/pull/10 (merged)
• https://github.com/DataValues/Common/pull/24 (merged)
• https://github.com/DataValues/Geo/pull/46 (merged)
• https://github.com/DataValues/Number/pull/28 (merged)
• https://github.com/DataValues/Time/pull/46 (merged)

ValueParserTestBase::getParserClass patches:

• Base: https://github.com/DataValues/Common/pull/23 (merged) and https://github.com/DataValues/Common/pull/25 (merged)
• https://github.com/DataValues/Geo/pull/44 (merged)
• https://github.com/DataValues/Number/pull/26 (merged)
• https://github.com/DataValues/Time/pull/44 (merged)
• https://gerrit.wikimedia.org/r/#/c/194531/ (merged)