Add a base test

Currently, it just strips source data.  This should be shared with other import tests.

Change-Id: I974878a5bc6c567faa88ca50b379495f61d8e946
More robust common check import functions

Handles minor differences in amount fields; use basic gross
and currency instead of explicit original_- fields.

Change-Id: I7bda16ee81e4aa35a498ab905ca710bdb317ac6b
Merge changes I7bda16ee,I974878a5

* changes:
  More robust common check import functions
  Add a base test