test nix_state_create's lookupPath argument

(cherry picked from commit 6e5a259f60725b632e52d4839e6e3c285d6971d4)

rust/Cargo.lock

@@ -98,6 +98,12 @@ dependencies = [
  "windows-sys 0.52.0",
 ]
 
+[[package]]
+name = "fastrand"
+version = "2.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9fc0510504f03c51ada170672ac806f1f105a88aa97a5281117e1ddc3368e51a"
+
 [[package]]
 name = "glob"
 version = "0.3.1"
@@ -192,6 +198,7 @@ dependencies = [
  "nix-c-raw",
  "nix-store",
  "nix-util",
+ "tempfile",
 ]
 
 [[package]]
@@ -339,6 +346,18 @@ dependencies = [
  "unicode-ident",
 ]
 
+[[package]]
+name = "tempfile"
+version = "3.10.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "85b77fafb263dd9d05cbeac119526425676db3784113aa9295c88498cbf8bff1"
+dependencies = [
+ "cfg-if",
+ "fastrand",
+ "rustix",
+ "windows-sys 0.52.0",
+]
+
 [[package]]
 name = "unicode-ident"
 version = "1.0.12"

rust/nix-expr/Cargo.toml

@@ -11,4 +11,5 @@ nix-store = { path = "../nix-store" }
 nix-util = { path = "../nix-util" }
 nix-c-raw = { path = "../nix-c-raw" }
 lazy_static = "1.4.0"
-ctor = "0.2.7"
+ctor = "0.2.7"
+tempfile = "3.10.1"

rust/nix-expr/src/eval_state.rs

@@ -385,6 +385,7 @@ pub fn test_init() {
 #[cfg(test)]
 mod tests {
     use ctor::ctor;
+    use std::io::Write as _;
 
     use super::*;
 
@@ -403,6 +404,37 @@ mod tests {
         .unwrap();
     }
 
+    #[test]
+    fn eval_state_lookup_path() {
+        let import_expression = "import <test_file0> + import <test_file1>";
+        let integer0 = 83;
+        let integer1 = 103;
+        let mut test_file0 = tempfile::NamedTempFile::new().unwrap();
+        let mut test_file1 = tempfile::NamedTempFile::new().unwrap();
+        writeln!(test_file0, "{integer0}").unwrap();
+        writeln!(test_file1, "{integer1}").unwrap();
+        gc_registering_current_thread(|| {
+            let es = EvalState::new(Store::open("auto").unwrap(), []).unwrap();
+            assert!(es.eval_from_string(import_expression, "<test>").is_err());
+
+            let es = EvalState::new(
+                Store::open("auto").unwrap(),
+                [
+                    format!("test_file0={}", test_file0.path().to_str().unwrap()).as_str(),
+                    format!("test_file1={}", test_file1.path().to_str().unwrap()).as_str(),
+                ],
+            )
+            .unwrap();
+            let v = es
+                .require_int(&es.eval_from_string(import_expression, "<test>").unwrap())
+                .unwrap();
+            assert_eq!(v, integer0 + integer1);
+        })
+        .unwrap();
+        test_file0.close().unwrap();
+        test_file1.close().unwrap();
+    }
+
     #[test]
     fn eval_state_eval_from_string() {
         gc_registering_current_thread(|| {