Revert "Issue #2256405 by blueminds: VocabularyUnitTest and VocabularyTest are misnamed."

This reverts commit b293020054d2c7a0c9252bf59690a55b0a7ca847.
Issue #2256405 by blueminds: VocabularyUnitTest and VocabularyTest are misnamed.
Issue #2256405: VocabularyUnitTest and VocabularyTest are misnamed.