Summary

A common pattern in csuite tests is that we create empty sentinel files in the database directory to indicate that something has finished, e.g., a backup or a checkpoint. As this is a common pattern, we should add convenience functions for it.

Suggested approach

We should add the following functions:

• A function to create a sentinel file, e.g., testutil_sentinel(dir, file)
• A function to check whether a file exists. We can possibly have two variants, e.g.,  testutil_exists(file) and testutil_exists2(dir, file) (I'm not sure if this is the best name though.)