There is a AndroidGroupTest class, where we could put a testAdd_readOnly test that checks whether the read-only flag is set
For the more important data rows: my suggestion is to just test newDataRow in DataBuilder. So we could create a TestDataRowBuilder that extends DataRowBuilder and whose build() just returns one data row created by newDataRow(). The test could then check if the data row returned by build() contains the correct read-only column (2 cases).
Good thinking. I implemented the requested changes :)
Good thinking. I implemented the requested changes :)