feat(tvix/tests): check in Nix' language test suite r/4461

This adds scaffolding code for running the Nix language test suite.

The majority of eval-okay-* tests should eventually be runnable as-is
by Tvix, however the eval-fail-* tests might not as we intend to have
more useful error messages than upstream Nix.

Change-Id: I4f3227f0889c55e4274b804a3072850fb78dd1bd
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6126
Tested-by: BuildkiteCI
Autosubmit: tazjin <tazjin@tvl.su>
Reviewed-by: grfn <grfn@gws.fyi>

1 files changed, 10 insertions, 0 deletions

diff --git a/tvix/eval/src/tests/nix_tests/eval-okay-attrs2.nix b/tvix/eval/src/tests/nix_tests/eval-okay-attrs2.nix
new file mode 100644
index 000000000000..9e06b83ac1fd
--- /dev/null
+++ b/tvix/eval/src/tests/nix_tests/eval-okay-attrs2.nix
@@ -0,0 +1,10 @@
+let {
+  as = { x = 123; y = 456; } // { z = 789; } // { z = 987; };
+
+  A = "a";
+  Z = "z";
+
+  body = if builtins.hasAttr A as
+         then builtins.getAttr A as
+         else assert builtins.hasAttr Z as; builtins.getAttr Z as;
+}