- when running scripts under the exec wrapper, ensure that directories in
`sys.path` contain no potentially importable names not present in the
production environment
Goal: for each test run to produce reproducible output, allowing us to check
for possible stochastic behavior in the scripts, as well as output-related
regressions (for example, garbage or improperly formatted output produced by a
bad format string) that might not be detected by the test scripts.
In practice, bugginess of the pexpect module and the non-deterministic behavior
of Bitcoin Core’s regtest implementation preclude completely identical output
from test run to test run, but the differences are small enough to result in an
easily reviewable diff.
Enable this feature by setting the MMGEN_TEST_SUITE_DETERMINISTIC environment
variable or running test/test-release.sh with the -D switch.
Examples:
$ script -c 'test/test-release.sh -FDv quick' -O run1
$ script -c 'test/test-release.sh -FDv quick' -O run2
# (optionally remove control characters from output files)
$ diff -u run1 run2 > diff
$ export MMGEN_TEST_SUITE_DETERMINISTIC=1
$ script -c 'test/test.py -ne main' -O run1
$ script -c 'test/test.py -ne main' -O run2
# (optionally remove control characters from output files)
$ diff -u run1 run2 > diff
Rationale of this commit: to relocate some ugly test-related code from the MMGen
package tree to the test tree, as well as to enable deterministic testing
(implemented in the next commit).
The overlay tree is a symlinked mirror of the MMGen package dir with a few
monkey-patched modules.
The monkey-patching is conditional, so the modules are certain to get tested in
their unpatched state as well.
