The Data Normalizer on a Data Identifier only works if there is a Validator associated with that Data Identifier.
The Data Identifier Normalizer kicks in after pattern matching and before the Validator is applied. If the Data Identifier does not have a Validator, the matched content will not be normalized.
If you have a list of keywords including test, and the normalizer is set to lower case, it will not match:
Test
tEST
TesT
Until a validator is added.
In this case, it is better to use a keyword than a Data Identifier.