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

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>

tools/depotfmt.nix

@@ -23,8 +23,7 @@ let
     command = "${pkgs.nixpkgs-fmt}/bin/nixpkgs-fmt"
     includes = [ "*.nix" ]
     excludes = [
-      "third_party/nix/tests/*",
-      "third_party/nix/src/tests/*"
+      "tvix/eval/src/tests/*",
     ]
 
     [formatter.rust]

tvix/eval/.skip-subtree

@@ -0,0 +1,2 @@
+Do not traverse further, readTree will encounter Nix language tests
+and such and fail.

tvix/eval/src/eval.rs

@@ -1,9 +1,9 @@
 use rnix::{self, types::TypedNode};
 
-use crate::errors::EvalResult;
+use crate::{errors::EvalResult, value::Value};
 
-pub fn interpret(code: String) -> EvalResult<String> {
-    let ast = rnix::parse(&code);
+pub fn interpret(code: &str) -> EvalResult<Value> {
+    let ast = rnix::parse(code);
 
     let errors = ast.errors();
     if !errors.is_empty() {
@@ -15,6 +15,5 @@ pub fn interpret(code: String) -> EvalResult<String> {
     let code = crate::compiler::compile(ast)?;
     println!("code: {:?}", code);
 
-    let value = crate::vm::run_chunk(code)?;
-    Ok(format!("value: {} :: {}", value, value.type_of()))
+    crate::vm::run_chunk(code)
 }

tvix/eval/src/main.rs

@@ -12,6 +12,9 @@ mod opcode;
 mod value;
 mod vm;
 
+#[cfg(test)]
+mod tests;
+
 fn main() {
     let mut args = env::args();
     if args.len() > 2 {
@@ -47,8 +50,8 @@ fn run_prompt() {
 }
 
 fn run(code: String) {
-    match eval::interpret(code) {
-        Ok(result) => println!("=> {}", result),
+    match eval::interpret(&code) {
+        Ok(result) => println!("=> {} :: {}", result, result.type_of()),
         Err(err) => eprintln!("{}", err),
     }
 }

tvix/eval/src/tests/mod.rs

@@ -0,0 +1,28 @@
+use crate::eval::interpret;
+
+use test_generator::test_resources;
+
+// eval-okay-* tests contain a snippet of Nix code, and an expectation
+// of the produced string output of the evaluator.
+//
+// These evaluations are always supposed to succeed, i.e. all snippets
+// are guaranteed to be valid Nix code.
+#[test_resources("src/tests/nix_tests/eval-okay-*.nix")]
+fn eval_okay(code_path: &str) {
+    let base = code_path
+        .strip_suffix("nix")
+        .expect("test files always end in .nix");
+    let exp_path = format!("{}exp", base);
+
+    let code = std::fs::read_to_string(code_path).expect("should be able to read test code");
+    let exp = std::fs::read_to_string(exp_path).expect("should be able to read test expectation");
+
+    let result = interpret(&code).expect("evaluation of eval-okay test should succeed");
+    let result_str = format!("{}", result);
+
+    assert_eq!(
+        exp.trim(),
+        result_str,
+        "result value (and its representation) must match expectation"
+    );
+}

tvix/eval/src/tests/nix_tests/README.md

@@ -0,0 +1,8 @@
+These test definitions are taken from the Nix 2.3 code base, they can
+be found upstream at:
+
+  https://github.com/NixOS/nix/tree/2.3.16/tests/lang
+
+These tests follow the licensing directions of Nix 2.3 itself:
+
+  https://github.com/NixOS/nix/blob/2.3.16/COPYING

tvix/eval/src/tests/nix_tests/data

@@ -0,0 +1 @@
+foo

tvix/eval/src/tests/nix_tests/dir1/a.nix

@@ -0,0 +1 @@
+"a"

tvix/eval/src/tests/nix_tests/dir2/a.nix

@@ -0,0 +1 @@
+"X"

tvix/eval/src/tests/nix_tests/dir2/b.nix

@@ -0,0 +1 @@
+"b"

tvix/eval/src/tests/nix_tests/dir3/a.nix

@@ -0,0 +1 @@
+"X"

tvix/eval/src/tests/nix_tests/dir3/b.nix

@@ -0,0 +1 @@
+"X"

tvix/eval/src/tests/nix_tests/dir3/c.nix

@@ -0,0 +1 @@
+"c"

tvix/eval/src/tests/nix_tests/dir4/a.nix

@@ -0,0 +1 @@
+"X"

tvix/eval/src/tests/nix_tests/dir4/c.nix

@@ -0,0 +1 @@
+"X"

tvix/eval/src/tests/nix_tests/eval-fail-abort.nix

@@ -0,0 +1 @@
+if true then abort "this should fail" else 1

tvix/eval/src/tests/nix_tests/eval-fail-antiquoted-path.nix

@@ -0,0 +1,4 @@
+# This must fail to evaluate, since ./fnord doesn't exist.  If it did
+# exist, it would produce "/nix/store/<hash>-fnord/xyzzy" (with an
+# appropriate context).
+"${./fnord}/xyzzy"

tvix/eval/src/tests/nix_tests/eval-fail-assert.nix

@@ -0,0 +1,5 @@
+let {
+  x = arg: assert arg == "y"; 123;
+
+  body = x "x";
+}

tvix/eval/src/tests/nix_tests/eval-fail-bad-antiquote-1.nix

@@ -0,0 +1 @@
+"${x: x}"

tvix/eval/src/tests/nix_tests/eval-fail-bad-antiquote-2.nix

@@ -0,0 +1 @@
+"${./fnord}"

tvix/eval/src/tests/nix_tests/eval-fail-bad-antiquote-3.nix

@@ -0,0 +1 @@
+''${x: x}''

tvix/eval/src/tests/nix_tests/eval-fail-blackhole.nix

@@ -0,0 +1,5 @@
+let {
+  body = x;
+  x = y;
+  y = x;
+}

tvix/eval/src/tests/nix_tests/eval-fail-deepseq.nix

@@ -0,0 +1 @@
+builtins.deepSeq { x = abort "foo"; } 456

tvix/eval/src/tests/nix_tests/eval-fail-hashfile-missing.nix

@@ -0,0 +1,5 @@
+let
+  paths = [ ./this-file-is-definitely-not-there-7392097 "/and/neither/is/this/37293620" ];
+in
+  toString (builtins.concatLists (map (hash: map (builtins.hashFile hash) paths) ["md5" "sha1" "sha256" "sha512"]))
+

tvix/eval/src/tests/nix_tests/eval-fail-missing-arg.nix

@@ -0,0 +1 @@
+({x, y, z}: x + y + z) {x = "foo"; z = "bar";}

tvix/eval/src/tests/nix_tests/eval-fail-path-slash.nix

@@ -0,0 +1,6 @@
+# Trailing slashes in paths are not allowed.
+# This restriction could be lifted sometime,
+# for example if we make '/' a path concatenation operator.
+# See https://github.com/NixOS/nix/issues/1138
+# and https://nixos.org/nix-dev/2016-June/020829.html
+/nix/store/

tvix/eval/src/tests/nix_tests/eval-fail-remove.nix

@@ -0,0 +1,5 @@
+let {
+  attrs = {x = 123; y = 456;};
+
+  body = (removeAttrs attrs ["x"]).x;
+}

tvix/eval/src/tests/nix_tests/eval-fail-scope-5.nix

@@ -0,0 +1,10 @@
+let {
+
+  x = "a";
+  y = "b";
+
+  f = {x ? y, y ? x}: x + y;
+
+  body = f {};
+
+}

tvix/eval/src/tests/nix_tests/eval-fail-seq.nix

@@ -0,0 +1 @@
+builtins.seq (abort "foo") 2

tvix/eval/src/tests/nix_tests/eval-fail-substring.nix

@@ -0,0 +1 @@
+builtins.substring (builtins.sub 0 1) 1 "x"

tvix/eval/src/tests/nix_tests/eval-fail-to-path.nix

@@ -0,0 +1 @@
+builtins.toPath "foo/bar"

tvix/eval/src/tests/nix_tests/eval-fail-undeclared-arg.nix

@@ -0,0 +1 @@
+({x, z}: x + z) {x = "foo"; y = "bla"; z = "bar";}

tvix/eval/src/tests/nix_tests/eval-okay-any-all.exp

@@ -0,0 +1 @@
+[ false false true true true true false true ]

tvix/eval/src/tests/nix_tests/eval-okay-any-all.nix

@@ -0,0 +1,11 @@
+with builtins;
+
+[ (any (x: x == 1) [])
+  (any (x: x == 1) [2 3 4])
+  (any (x: x == 1) [1 2 3 4])
+  (any (x: x == 1) [4 3 2 1])
+  (all (x: x == 1) [])
+  (all (x: x == 1) [1])
+  (all (x: x == 1) [1 2 3])
+  (all (x: x == 1) [1 1 1])
+]

tvix/eval/src/tests/nix_tests/eval-okay-arithmetic.exp

@@ -0,0 +1 @@
+2216

tvix/eval/src/tests/nix_tests/eval-okay-arithmetic.nix

@@ -0,0 +1,59 @@
+with import ./lib.nix;
+
+let {
+
+  /* Supposedly tail recursive version:
+
+  range_ = accum: first: last:
+    if first == last then ([first] ++ accum)
+    else range_ ([first] ++ accum) (builtins.add first 1) last;
+
+  range = range_ [];
+  */
+
+  x = 12;
+
+  err = abort "urgh";
+
+  body = sum
+    [ (sum (range 1 50))
+      (123 + 456)
+      (0 + -10 + -(-11) + -x)
+      (10 - 7 - -2)
+      (10 - (6 - -1))
+      (10 - 1 + 2)
+      (3 * 4 * 5)
+      (56088 / 123 / 2)
+      (3 + 4 * const 5 0 - 6 / id 2)
+
+      (builtins.bitAnd 12 10) # 0b1100 & 0b1010 =  8
+      (builtins.bitOr  12 10) # 0b1100 | 0b1010 = 14
+      (builtins.bitXor 12 10) # 0b1100 ^ 0b1010 =  6
+
+      (if 3 < 7 then 1 else err)
+      (if 7 < 3 then err else 1)
+      (if 3 < 3 then err else 1)
+
+      (if 3 <= 7 then 1 else err)
+      (if 7 <= 3 then err else 1)
+      (if 3 <= 3 then 1 else err)
+
+      (if 3 > 7 then err else 1)
+      (if 7 > 3 then 1 else err)
+      (if 3 > 3 then err else 1)
+
+      (if 3 >= 7 then err else 1)
+      (if 7 >= 3 then 1 else err)
+      (if 3 >= 3 then 1 else err)
+
+      (if 2 > 1 == 1 < 2 then 1 else err)
+      (if 1 + 2 * 3 >= 7 then 1 else err)
+      (if 1 + 2 * 3 < 7 then err else 1)
+
+      # Not integer, but so what.
+      (if "aa" < "ab" then 1 else err)
+      (if "aa" < "aa" then err else 1)
+      (if "foo" < "foobar" then 1 else err)
+    ];
+
+}

tvix/eval/src/tests/nix_tests/eval-okay-attrnames.exp

@@ -0,0 +1 @@
+"newxfoonewxy"

tvix/eval/src/tests/nix_tests/eval-okay-attrnames.nix

@@ -0,0 +1,11 @@
+with import ./lib.nix;
+
+let
+
+  attrs = {y = "y"; x = "x"; foo = "foo";} // rec {x = "newx"; bar = x;};
+
+  names = builtins.attrNames attrs;
+
+  values = map (name: builtins.getAttr name attrs) names;
+
+in assert values == builtins.attrValues attrs; concat values

tvix/eval/src/tests/nix_tests/eval-okay-attrs.exp

@@ -0,0 +1 @@
+987

tvix/eval/src/tests/nix_tests/eval-okay-attrs.nix

@@ -0,0 +1,5 @@
+let {
+  as = { x = 123; y = 456; } // { z = 789; } // { z = 987; };
+
+  body = if as ? a then as.a else assert as ? z; as.z;
+}

tvix/eval/src/tests/nix_tests/eval-okay-attrs2.exp

@@ -0,0 +1 @@
+987

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;
+}

tvix/eval/src/tests/nix_tests/eval-okay-attrs3.exp

@@ -0,0 +1 @@
+"foo 22 80 itchyxac"

tvix/eval/src/tests/nix_tests/eval-okay-attrs3.nix

@@ -0,0 +1,22 @@
+let
+
+  config = 
+    {
+      services.sshd.enable = true;
+      services.sshd.port = 22;
+      services.httpd.port = 80;
+      hostName = "itchy";
+      a.b.c.d.e.f.g.h.i.j.k.l.m.n.o.p.q.r.s.t.u.v.w.x.y.z = "x";
+      foo = {
+        a = "a";
+        b.c = "c";
+      };
+    };
+
+in
+  if config.services.sshd.enable
+  then "foo ${toString config.services.sshd.port} ${toString config.services.httpd.port} ${config.hostName}"
+       + "${config.a.b.c.d.e.f.g.h.i.j.k.l.m.n.o.p.q.r.s.t.u.v.w.x.y.z}"
+       + "${config.foo.a}"
+       + "${config.foo.b.c}"
+  else "bar"

tvix/eval/src/tests/nix_tests/eval-okay-attrs4.exp

@@ -0,0 +1 @@
+[ true false true false false true false false ]

tvix/eval/src/tests/nix_tests/eval-okay-attrs4.nix

@@ -0,0 +1,7 @@
+let
+
+  as = { x.y.z = 123; a.b.c = 456; };
+
+  bs = null;
+
+in [ (as ? x) (as ? y) (as ? x.y.z) (as ? x.y.z.a) (as ? x.y.a) (as ? a.b.c) (bs ? x) (bs ? x.y.z) ]

tvix/eval/src/tests/nix_tests/eval-okay-attrs5.exp

@@ -0,0 +1 @@
+[ 123 "foo" 456 456 "foo" "xyzzy" "xyzzy" true ]

tvix/eval/src/tests/nix_tests/eval-okay-attrs5.nix

@@ -0,0 +1,21 @@
+with import ./lib.nix;
+
+let
+
+  as = { x.y.z = 123; a.b.c = 456; };
+
+  bs = { f-o-o.bar = "foo"; };
+
+  or = x: y: x || y;
+  
+in
+  [ as.x.y.z
+    as.foo or "foo"
+    as.x.y.bla or as.a.b.c
+    as.a.b.c or as.x.y.z
+    as.x.y.bla or bs.f-o-o.bar or "xyzzy"
+    as.x.y.bla or bs.bar.foo or "xyzzy"
+    (123).bla or null.foo or "xyzzy"
+    # Backwards compatibility test.
+    (fold or [] [true false false])
+  ]

tvix/eval/src/tests/nix_tests/eval-okay-attrs6.exp

@@ -0,0 +1 @@
+{ __overrides = { bar = "qux"; }; bar = "qux"; foo = "bar"; }

tvix/eval/src/tests/nix_tests/eval-okay-attrs6.nix

@@ -0,0 +1,4 @@
+rec {
+  "${"foo"}" = "bar";
+   __overrides = { bar = "qux"; };
+}

tvix/eval/src/tests/nix_tests/eval-okay-autoargs.exp

@@ -0,0 +1 @@
+"xyzzy!xyzzy!foobar"

tvix/eval/src/tests/nix_tests/eval-okay-autoargs.flags

@@ -0,0 +1 @@
+--arg lib import(lang/lib.nix) --argstr xyzzy xyzzy! -A result

tvix/eval/src/tests/nix_tests/eval-okay-autoargs.nix

@@ -0,0 +1,15 @@
+let
+
+  foobar = "foobar";
+
+in
+
+{ xyzzy2 ? xyzzy # mutually recursive args
+, xyzzy ? "blaat" # will be overridden by --argstr
+, fb ? foobar
+, lib # will be set by --arg
+}:
+
+{
+  result = lib.concat [xyzzy xyzzy2 fb];
+}

tvix/eval/src/tests/nix_tests/eval-okay-backslash-newline-1.exp

@@ -0,0 +1 @@
+"a\nb"

tvix/eval/src/tests/nix_tests/eval-okay-backslash-newline-1.nix

@@ -0,0 +1,2 @@
+"a\
+b"

tvix/eval/src/tests/nix_tests/eval-okay-backslash-newline-2.exp

@@ -0,0 +1 @@
+"a\nb"

tvix/eval/src/tests/nix_tests/eval-okay-backslash-newline-2.nix

@@ -0,0 +1,2 @@
+''a''\
+b''

tvix/eval/src/tests/nix_tests/eval-okay-builtins-add.exp

@@ -0,0 +1 @@
+[ 5 4 "int" "tt" "float" 4 ]

tvix/eval/src/tests/nix_tests/eval-okay-builtins-add.nix

@@ -0,0 +1,8 @@
+[
+(builtins.add 2 3)
+(builtins.add 2 2)
+(builtins.typeOf (builtins.add 2  2))
+("t" + "t")
+(builtins.typeOf (builtins.add 2.0 2))
+(builtins.add 2.0 2)
+]

tvix/eval/src/tests/nix_tests/eval-okay-builtins.exp

@@ -0,0 +1 @@
+/foo

tvix/eval/src/tests/nix_tests/eval-okay-builtins.nix

@@ -0,0 +1,12 @@
+assert builtins ? currentSystem;
+assert !builtins ? __currentSystem;
+
+let {
+
+  x = if builtins ? dirOf then builtins.dirOf /foo/bar else "";
+
+  y = if builtins ? fnord then builtins.fnord "foo" else "";
+
+  body = x + y;
+  
+}

tvix/eval/src/tests/nix_tests/eval-okay-callable-attrs.exp

@@ -0,0 +1 @@
+true

tvix/eval/src/tests/nix_tests/eval-okay-callable-attrs.nix

@@ -0,0 +1 @@
+({ __functor = self: x: self.foo && x; foo = false; } // { foo = true; }) true

tvix/eval/src/tests/nix_tests/eval-okay-catattrs.exp

@@ -0,0 +1 @@
+[ 1 2 ]

tvix/eval/src/tests/nix_tests/eval-okay-catattrs.nix

@@ -0,0 +1 @@
+builtins.catAttrs "a" [ { a = 1; } { b = 0; } { a = 2; } ]

tvix/eval/src/tests/nix_tests/eval-okay-closure.exp.xml

@@ -0,0 +1,343 @@
+<?xml version='1.0' encoding='utf-8'?>
+<expr>
+  <list>
+    <attrs>
+      <attr name="foo">
+        <bool value="true" />
+      </attr>
+      <attr name="key">
+        <int value="-13" />
+      </attr>
+    </attrs>
+    <attrs>
+      <attr name="foo">
+        <bool value="true" />
+      </attr>
+      <attr name="key">
+        <int value="-12" />
+      </attr>
+    </attrs>
+    <attrs>
+      <attr name="foo">
+        <bool value="true" />
+      </attr>
+      <attr name="key">
+        <int value="-11" />
+      </attr>
+    </attrs>
+    <attrs>
+      <attr name="foo">
+        <bool value="true" />
+      </attr>
+      <attr name="key">
+        <int value="-9" />
+      </attr>
+    </attrs>
+    <attrs>
+      <attr name="foo">
+        <bool value="true" />
+      </attr>
+      <attr name="key">
+        <int value="-8" />
+      </attr>
+    </attrs>
+    <attrs>
+      <attr name="foo">
+        <bool value="true" />
+      </attr>
+      <attr name="key">
+        <int value="-7" />
+      </attr>
+    </attrs>
+    <attrs>
+      <attr name="foo">
+        <bool value="true" />
+      </attr>
+      <attr name="key">
+        <int value="-5" />
+      </attr>
+    </attrs>
+    <attrs>
+      <attr name="foo">
+        <bool value="true" />
+      </attr>
+      <attr name="key">
+        <int value="-4" />
+      </attr>
+    </attrs>
+    <attrs>
+      <attr name="foo">
+        <bool value="true" />
+      </attr>
+      <attr name="key">
+        <int value="-3" />
+      </attr>
+    </attrs>
+    <attrs>
+      <attr name="key">
+        <int value="-1" />
+      </attr>
+    </attrs>
+    <attrs>
+      <attr name="foo">
+        <bool value="true" />
+      </attr>
+      <attr name="key">
+        <int value="0" />
+      </attr>
+    </attrs>
+    <attrs>
+      <attr name="foo">
+        <bool value="true" />
+      </attr>
+      <attr name="key">
+        <int value="1" />
+      </attr>
+    </attrs>
+    <attrs>
+      <attr name="foo">
+        <bool value="true" />
+      </attr>
+      <attr name="key">
+        <int value="2" />
+      </attr>
+    </attrs>
+    <attrs>
+      <attr name="foo">
+        <bool value="true" />
+      </attr>
+      <attr name="key">
+        <int value="4" />
+      </attr>
+    </attrs>
+    <attrs>
+      <attr name="foo">
+        <bool value="true" />
+      </attr>
+      <attr name="key">
+        <int value="5" />
+      </attr>
+    </attrs>
+    <attrs>
+      <attr name="foo">
+        <bool value="true" />
+      </attr>
+      <attr name="key">
+        <int value="6" />
+      </attr>
+    </attrs>
+    <attrs>
+      <attr name="key">
+        <int value="8" />
+      </attr>
+    </attrs>
+    <attrs>
+      <attr name="foo">
+        <bool value="true" />
+      </attr>
+      <attr name="key">
+        <int value="9" />
+      </attr>
+    </attrs>
+    <attrs>
+      <attr name="foo">
+        <bool value="true" />
+      </attr>
+      <attr name="key">
+        <int value="10" />
+      </attr>
+    </attrs>
+    <attrs>
+      <attr name="foo">
+        <bool value="true" />
+      </attr>
+      <attr name="key">
+        <int value="13" />
+      </attr>
+    </attrs>
+    <attrs>
+      <attr name="foo">
+        <bool value="true" />
+      </attr>
+      <attr name="key">
+        <int value="14" />
+      </attr>
+    </attrs>
+    <attrs>
+      <attr name="foo">
+        <bool value="true" />
+      </attr>
+      <attr name="key">
+        <int value="15" />
+      </attr>
+    </attrs>
+    <attrs>
+      <attr name="key">
+        <int value="17" />
+      </attr>
+    </attrs>
+    <attrs>
+      <attr name="foo">
+        <bool value="true" />
+      </attr>
+      <attr name="key">
+        <int value="18" />
+      </attr>
+    </attrs>
+    <attrs>
+      <attr name="foo">
+        <bool value="true" />
+      </attr>
+      <attr name="key">
+        <int value="19" />
+      </attr>
+    </attrs>
+    <attrs>
+      <attr name="foo">
+        <bool value="true" />
+      </attr>
+      <attr name="key">
+        <int value="22" />
+      </attr>
+    </attrs>
+    <attrs>
+      <attr name="foo">
+        <bool value="true" />
+      </attr>
+      <attr name="key">
+        <int value="23" />
+      </attr>
+    </attrs>
+    <attrs>
+      <attr name="key">
+        <int value="26" />
+      </attr>
+    </attrs>
+    <attrs>
+      <attr name="foo">
+        <bool value="true" />
+      </attr>
+      <attr name="key">
+        <int value="27" />
+      </attr>
+    </attrs>
+    <attrs>
+      <attr name="foo">
+        <bool value="true" />
+      </attr>
+      <attr name="key">
+        <int value="28" />
+      </attr>
+    </attrs>
+    <attrs>
+      <attr name="foo">
+        <bool value="true" />
+      </attr>
+      <attr name="key">
+        <int value="31" />
+      </attr>
+    </attrs>
+    <attrs>
+      <attr name="foo">
+        <bool value="true" />
+      </attr>
+      <attr name="key">
+        <int value="32" />
+      </attr>
+    </attrs>
+    <attrs>
+      <attr name="key">
+        <int value="35" />
+      </attr>
+    </attrs>
+    <attrs>
+      <attr name="foo">
+        <bool value="true" />
+      </attr>
+      <attr name="key">
+        <int value="36" />
+      </attr>
+    </attrs>
+    <attrs>
+      <attr name="foo">
+        <bool value="true" />
+      </attr>
+      <attr name="key">
+        <int value="40" />
+      </attr>
+    </attrs>
+    <attrs>
+      <attr name="foo">
+        <bool value="true" />
+      </attr>
+      <attr name="key">
+        <int value="41" />
+      </attr>
+    </attrs>
+    <attrs>
+      <attr name="key">
+        <int value="44" />
+      </attr>
+    </attrs>
+    <attrs>
+      <attr name="foo">
+        <bool value="true" />
+      </attr>
+      <attr name="key">
+        <int value="45" />
+      </attr>
+    </attrs>
+    <attrs>
+      <attr name="foo">
+        <bool value="true" />
+      </attr>
+      <attr name="key">
+        <int value="49" />
+      </attr>
+    </attrs>
+    <attrs>
+      <attr name="key">
+        <int value="53" />
+      </attr>
+    </attrs>
+    <attrs>
+      <attr name="foo">
+        <bool value="true" />
+      </attr>
+      <attr name="key">
+        <int value="54" />
+      </attr>
+    </attrs>
+    <attrs>
+      <attr name="foo">
+        <bool value="true" />
+      </attr>
+      <attr name="key">
+        <int value="58" />
+      </attr>
+    </attrs>
+    <attrs>
+      <attr name="key">
+        <int value="62" />
+      </attr>
+    </attrs>
+    <attrs>
+      <attr name="foo">
+        <bool value="true" />
+      </attr>
+      <attr name="key">
+        <int value="67" />
+      </attr>
+    </attrs>
+    <attrs>
+      <attr name="key">
+        <int value="71" />
+      </attr>
+    </attrs>
+    <attrs>
+      <attr name="key">
+        <int value="80" />
+      </attr>
+    </attrs>
+  </list>
+</expr>

tvix/eval/src/tests/nix_tests/eval-okay-closure.nix

@@ -0,0 +1,13 @@
+let
+
+  closure = builtins.genericClosure {
+    startSet = [{key = 80;}];
+    operator = {key, foo ? false}:
+      if builtins.lessThan key 0
+      then []
+      else [{key = builtins.sub key 9;} {key = builtins.sub key 13; foo = true;}];
+  };
+
+  sort = (import ./lib.nix).sortBy (a: b: builtins.lessThan a.key b.key);
+
+in sort closure

tvix/eval/src/tests/nix_tests/eval-okay-comments.exp

@@ -0,0 +1 @@
+"abcdefghijklmnopqrstuvwxyz"

tvix/eval/src/tests/nix_tests/eval-okay-comments.nix

@@ -0,0 +1,59 @@
+# A simple comment
+"a"+ # And another
+## A double comment
+"b"+  ## And another
+# Nested # comments #
+"c"+   # and # some # other #
+# An empty line, following here:
+
+"d"+      # and a comment not starting the line !
+
+"e"+
+/* multiline comments */
+"f" +
+/* multiline
+   comments,
+   on
+   multiple
+   lines
+*/
+"g" +
+# Small, tricky comments
+/**/ "h"+ /*/*/ "i"+ /***/ "j"+ /* /*/ "k"+ /*/* /*/ "l"+
+# Comments with an even number of ending '*' used to fail:
+"m"+
+/* */ /* **/ /* ***/ /* ****/ "n"+
+/* */ /** */ /*** */ /**** */ "o"+
+/** **/ /*** ***/ /**** ****/ "p"+
+/* * ** *** **** ***** */     "q"+
+# Random comments
+/* ***** ////// * / * / /* */ "r"+
+# Mixed comments
+/* # */
+"s"+
+# /* #
+"t"+
+# /* # */
+"u"+
+# /*********/
+"v"+
+## */*
+"w"+
+/*
+ * Multiline, decorated comments
+ * # This ain't a nest'd comm'nt
+ */
+"x"+
+''${/** with **/"y"
+  # real
+  /* comments
+     inside ! # */
+
+  # (and empty lines)
+
+}''+          /* And a multiline comment,
+                 on the same line,
+                 after some spaces
+*/             # followed by a one-line comment
+"z"
+/* EOF */

tvix/eval/src/tests/nix_tests/eval-okay-concat.exp

@@ -0,0 +1 @@
+[ 1 2 3 4 5 6 7 8 9 ]

tvix/eval/src/tests/nix_tests/eval-okay-concat.nix

@@ -0,0 +1 @@
+[1 2 3] ++ [4 5 6] ++ [7 8 9]

tvix/eval/src/tests/nix_tests/eval-okay-concatmap.exp

@@ -0,0 +1 @@
+[ [ 1 3 5 7 9 ] [ "a" "z" "b" "z" ] ]

tvix/eval/src/tests/nix_tests/eval-okay-concatmap.nix

@@ -0,0 +1,5 @@
+with import ./lib.nix;
+
+[ (builtins.concatMap (x: if x / 2 * 2 == x then [] else [ x ]) (range 0 10))
+  (builtins.concatMap (x: [x] ++ ["z"]) ["a" "b"])
+]

tvix/eval/src/tests/nix_tests/eval-okay-concatstringssep.exp

@@ -0,0 +1 @@
+[ "" "foobarxyzzy" "foo, bar, xyzzy" "foo" "" ]

tvix/eval/src/tests/nix_tests/eval-okay-concatstringssep.nix

@@ -0,0 +1,8 @@
+with builtins;
+
+[ (concatStringsSep "" [])
+  (concatStringsSep "" ["foo" "bar" "xyzzy"])
+  (concatStringsSep ", " ["foo" "bar" "xyzzy"])
+  (concatStringsSep ", " ["foo"])
+  (concatStringsSep ", " [])
+]

tvix/eval/src/tests/nix_tests/eval-okay-context-introspection.exp

@@ -0,0 +1 @@
+true

tvix/eval/src/tests/nix_tests/eval-okay-context-introspection.nix

@@ -0,0 +1,24 @@
+let
+  drv = derivation {
+    name = "fail";
+    builder = "/bin/false";
+    system = "x86_64-linux";
+    outputs = [ "out" "foo" ];
+  };
+
+  path = "${./eval-okay-context-introspection.nix}";
+
+  desired-context = {
+    "${builtins.unsafeDiscardStringContext path}" = {
+      path = true;
+    };
+    "${builtins.unsafeDiscardStringContext drv.drvPath}" = {
+      outputs = [ "foo" "out" ];
+      allOutputs = true;
+    };
+  };
+
+  legit-context = builtins.getContext "${path}${drv.outPath}${drv.foo.outPath}${drv.drvPath}";
+
+  constructed-context = builtins.getContext (builtins.appendContext "" desired-context);
+in legit-context == constructed-context

tvix/eval/src/tests/nix_tests/eval-okay-context.exp

@@ -0,0 +1 @@
+"foo eval-okay-context.nix bar"

tvix/eval/src/tests/nix_tests/eval-okay-context.nix

@@ -0,0 +1,6 @@
+let s = "foo ${builtins.substring 33 100 (baseNameOf "${./eval-okay-context.nix}")} bar";
+in
+  if s != "foo eval-okay-context.nix bar"
+  then abort "context not discarded"
+  else builtins.unsafeDiscardStringContext s
+

tvix/eval/src/tests/nix_tests/eval-okay-curpos.exp

@@ -0,0 +1 @@
+[ 3 7 4 9 ]

tvix/eval/src/tests/nix_tests/eval-okay-curpos.nix

@@ -0,0 +1,5 @@
+# Bla
+let
+  x = __curPos;
+    y = __curPos;
+in [ x.line x.column y.line y.column ]

tvix/eval/src/tests/nix_tests/eval-okay-deepseq.exp

@@ -0,0 +1 @@
+456

tvix/eval/src/tests/nix_tests/eval-okay-deepseq.nix

@@ -0,0 +1 @@
+builtins.deepSeq (let as = { x = 123; y = as; }; in as) 456

tvix/eval/src/tests/nix_tests/eval-okay-delayed-with-inherit.exp

@@ -0,0 +1 @@
+"b-overridden"

tvix/eval/src/tests/nix_tests/eval-okay-delayed-with-inherit.nix

@@ -0,0 +1,24 @@
+let
+  pkgs_ = with pkgs; {
+    a = derivation {
+      name = "a";
+      system = builtins.currentSystem;
+      builder = "/bin/sh";
+      args = [ "-c" "touch $out" ];
+      inherit b;
+    };
+
+    inherit b;
+  };
+
+  packageOverrides = p: {
+    b = derivation {
+      name = "b-overridden";
+      system = builtins.currentSystem;
+      builder = "/bin/sh";
+      args = [ "-c" "touch $out" ];
+    };
+  };
+
+  pkgs = pkgs_ // (packageOverrides pkgs_);
+in pkgs.a.b.name

tvix/eval/src/tests/nix_tests/eval-okay-delayed-with.exp

@@ -0,0 +1 @@
+"b-overridden b-overridden a"

tvix/eval/src/tests/nix_tests/eval-okay-delayed-with.nix

@@ -0,0 +1,29 @@
+let
+
+  pkgs_ = with pkgs; {
+    a = derivation {
+      name = "a";
+      system = builtins.currentSystem;
+      builder = "/bin/sh";
+      args = [ "-c" "touch $out" ];
+      inherit b;
+    };
+
+    b = derivation {
+      name = "b";
+      system = builtins.currentSystem;
+      builder = "/bin/sh";
+      args = [ "-c" "touch $out" ];
+      inherit a;
+    };
+
+    c = b;
+  };
+
+  packageOverrides = pkgs: with pkgs; {
+    b = derivation (b.drvAttrs // { name = "${b.name}-overridden"; });
+  };
+
+  pkgs = pkgs_ // (packageOverrides pkgs_);
+
+in "${pkgs.a.b.name} ${pkgs.c.name} ${pkgs.b.a.name}"

tvix/eval/src/tests/nix_tests/eval-okay-dynamic-attrs-2.exp

@@ -0,0 +1 @@
+true

tvix/eval/src/tests/nix_tests/eval-okay-dynamic-attrs-2.nix

@@ -0,0 +1 @@
+{ a."${"b"}" = true; a."${"c"}" = false; }.a.b

tvix/eval/src/tests/nix_tests/eval-okay-dynamic-attrs-bare.exp

@@ -0,0 +1 @@
+{ binds = true; hasAttrs = true; multiAttrs = true; recBinds = true; selectAttrs = true; selectOrAttrs = true; }

tvix/eval/src/tests/nix_tests/eval-okay-dynamic-attrs-bare.nix

@@ -0,0 +1,17 @@
+let
+  aString = "a";
+
+  bString = "b";
+in {
+  hasAttrs = { a.b = null; } ? ${aString}.b;
+
+  selectAttrs = { a.b = true; }.a.${bString};
+
+  selectOrAttrs = { }.${aString} or true;
+
+  binds = { ${aString}."${bString}c" = true; }.a.bc;
+
+  recBinds = rec { ${bString} = a; a = true; }.b;
+
+  multiAttrs = { ${aString} = true; ${bString} = false; }.a;
+}

tvix/eval/src/tests/nix_tests/eval-okay-dynamic-attrs.exp

@@ -0,0 +1 @@
+{ binds = true; hasAttrs = true; multiAttrs = true; recBinds = true; selectAttrs = true; selectOrAttrs = true; }

tvix/eval/src/tests/nix_tests/eval-okay-dynamic-attrs.nix

@@ -0,0 +1,17 @@
+let
+  aString = "a";
+
+  bString = "b";
+in {
+  hasAttrs = { a.b = null; } ? "${aString}".b;
+
+  selectAttrs = { a.b = true; }.a."${bString}";
+
+  selectOrAttrs = { }."${aString}" or true;
+
+  binds = { "${aString}"."${bString}c" = true; }.a.bc;
+
+  recBinds = rec { "${bString}" = a; a = true; }.b;
+
+  multiAttrs = { "${aString}" = true; "${bString}" = false; }.a;
+}

tvix/eval/src/tests/nix_tests/eval-okay-elem.exp

@@ -0,0 +1 @@
+[ true false 30 ]

tvix/eval/src/tests/nix_tests/eval-okay-elem.nix

@@ -0,0 +1,6 @@
+with import ./lib.nix;
+
+let xs = range 10 40; in
+
+[ (builtins.elem 23 xs) (builtins.elem 42 xs) (builtins.elemAt xs 20) ]
+

tvix/eval/src/tests/nix_tests/eval-okay-empty-args.exp

@@ -0,0 +1 @@
+"ab"

tvix/eval/src/tests/nix_tests/eval-okay-empty-args.nix

@@ -0,0 +1 @@
+({}: {x,y,}: "${x}${y}") {} {x = "a"; y = "b";}

tvix/eval/src/tests/nix_tests/eval-okay-eq-derivations.exp

@@ -0,0 +1 @@
+[ true true true false ]

tvix/eval/src/tests/nix_tests/eval-okay-eq-derivations.nix

@@ -0,0 +1,10 @@
+let
+
+  drvA1 = derivation { name = "a"; builder = "/foo"; system = "i686-linux"; };
+  drvA2 = derivation { name = "a"; builder = "/foo"; system = "i686-linux"; };
+  drvA3 = derivation { name = "a"; builder = "/foo"; system = "i686-linux"; } // { dummy = 1; };
+  
+  drvC1 = derivation { name = "c"; builder = "/foo"; system = "i686-linux"; };
+  drvC2 = derivation { name = "c"; builder = "/bar"; system = "i686-linux"; };
+
+in [ (drvA1 == drvA1) (drvA1 == drvA2) (drvA1 == drvA3) (drvC1 == drvC2) ]