The result of `import tests.nix {}` is now an attrset of tests.
This makes it easier and more efficient to evaluate or build multiple
tests in one call to `nix build`.
Simplify tests.nix by removing the large module args scope in favor of
self-contained scenario module definitions.
Add CPU core and memory size defaults to the test configuration to
enable building tests without `run-tests.sh`.
Add the following top-level args to tests.nix:
- `extraScenarios` to provide a nix-level way to define extra scenarios.
- `pkgs` to allow building tests with custom pkgs or systems.
1. fixedTest: Remove some unneeded layers of function calls.
2. Don't add a modified version of `black` to the global pkgs set.
Tests should not affect the pkgs of the tested system modules.
Fix the driver build script instead by adding an extra arg to the
call to `black`.
This improves debugging and experimenting by making it easy to compose fine-grained
scenarios that have specific tests and features enabled.
The VM test output now includes the subtest name and duration.
Remove the 'raise Exception()' hack for interactive mode.
Run 'banlist-and-restart' test before 'backups'. This speeds up the test
by avoiding an extra shutdown of all bitcoin-related services.
