If anyone wants to run wt2909_checkpoint_integrity, they might try running it this way and getting:

$ cd build_posix/test/csuite
$ test_wt2909_checkpoint_integrityRunning test command: ./test_wt2909_checkpoint_integrity 
Running test command: ./test_wt2909_checkpoint_integrity subtest -h WT_TEST.test_wt2909_checkpoint_integrity -v -p -o 1 -n 50000 
Running test command: subtest -h WT_TEST.test_wt2909_checkpoint_integrity -v -p -o 1 -n 50000 
test_wt2909_checkpoint_integrity: FAILED: check_results/122: session->open_cursor(session, "table:subtest", NULL, NULL, &maincur): No such file or directory
process aborting
Aborted (core dumped)

Unfortunately that results in an error (abort of a subprocess). It's not at all apparent that this test must be run as:

  $ cd build_posix/test
  $ ./csuite/test_wt2909_checkpoint_integrity

The directory position is relevant because a shared library extension is used for the test, and it is specified as a relative pathname. make check apparently runs the test from the build_posix/test directory, which is why it needs to continue to work from there.

One possible solution might be to check the current directory, and based on that, locate the shared library extension (that would allow us to run in either directory, which is probably all we need). Another solution might be to check that the shared library extension is where we need it to be, if not, issue an error.  Not as good, but much better than an unfathomable error/abort.