Nix can only build attrsets with a `type = "derivation"` attr.
Having the configuration's option-type as a passthru attr breaks the
ability to build specific test entries, since they are no longer
`type = "derivation"`.
This should be separate from `test-sources` because we want to re-use a
common instance of nixpkgs throughout those tests.
Also, moved the existing nixpkgs module test from `test-sources`.
This partially reverts commit c4ad4d0b2e.
Expose our locked nixpkgs as the `nixpkgs.source` module options.
This only happens when `evalNixvim` is part of a lib that was provided
`flake` as an argument.
Stubbed the `nixpkgs.source` option for now. Eventually, this will be
used to construct `pkgs` internally. For now, it's purely informational.
Based on the `nixpkgs.overlays` option available in NixOS, allows users
to further customize the `pkgs` instance used when evaluating nixvim.
The standard module tests are now provided a few extra module args to
enable a test where we instantiate a custom nixpkgs instance.
Allows using the `callPackage(s)` pattern on tests.
Rather than using `pkgs.callPackage`, we implement our own variant using
`lib.callPackageWith`.
Our variant (`callTest`) includes additional nixvim-specific stuff
commonly used by our tests.
Move the previous `default.nix` to `main.nix` so that `default.nix` can
be used for defining the set of all test derivations.
`main.nix` is imported by `default.nix`, but is only responsible for the
tests built from `tests/test-sources/`.
