Closes#193336Closes#261694
Related to #108984
The goal here was to get the following flake to build and run on
`aarch64-darwin`:
```nix
{ inputs.nixpkgs.url = <this branch>;
outputs = { nixpkgs, ... }: {
checks.aarch64-darwin.default =
nixpkgs.legacyPackages.aarch64-darwin.nixosTest {
name = "test";
nodes.machine = { };
testScript = "";
};
};
}
```
… and after this change it does. There's no longer a need for the
user to set `nodes.*.nixpkgs.pkgs` or
`nodes.*.virtualisation.host.pkgs` as the correct values are inferred
from the host system.
For `testBuildFailure` and similar functions, we need a full blown derivation and not a lazy one.
This is an internal option for test framework developers.
This is a decomposition of the testing-python.nix and build-vms.nix
files into modules.
By refactoring the glue, we accomplish the following:
- NixOS tests can now use `imports` and other module system features.
- Network-wide test setup can now be reusable; example:
- A setup with all VMs configured to use a DNS server
- Split long, slow tests into multiple tests that import a
common module that has most of the setup.
- Type checking for the test arguments
- (TBD) "generated" options reference docs
- Aspects that had to be wired through all the glue are now in their
own files.
- Chief example: interactive.nix.
- Also: network.nix
In rewriting this, I've generally stuck as close as possible to the
existing code; copying pieces of logic and rewiring them, without
changing the logic itself.
I've made two exceptions to this rule
- Introduction of `extraDriverArgs` instead of hardcoded
interactivity logic.
- Incorporation of https://github.com/NixOS/nixpkgs/pull/144110
in testScript.nix.
I might revert the latter and split it into a new commit.
