One of the most basic tests of data completeness is to verify that all the expected data gets loaded in the data warehouse. For example, validating all records, fields and full contents of each field are loaded. Some strategies are to compare record counts between source data, data loaded to the DW and rejected records if any. Make sure that all projected data is loaded into the data warehouse without any data loss or truncation.
You can achieve the above tests using Component/Query Test Plan: Once you complete this test, it will report records that are:
Only in Source but not in Target (rejected)
Only in Target but not in Source