More robust import tests

Everything I've done in previous PRs fixed issues with these tests. They test importing both using paths and strings, importing from the same folder, from a parent folder, from a child folder.

src/tests/builtins.rs

@@ -488,8 +488,46 @@ mod import {
     #[test]
     fn eval() {
         assert_eq!(
-            eval_ok("(builtins.import ./flake.nix).description"),
-            Value::Str("A reimplementation or nix in Rust.".into())
+            eval_ok("(builtins.import ./src/tests/import_tests/basic.nix).data"),
+            Value::Str("imported!".into())
+        );
+    }
+
+    #[test]
+    fn eval_same_folder_import() {
+        assert_eq!(
+            eval_ok("(builtins.import ./src/tests/import_tests/same-folder-import.nix).dataPath"),
+            Value::Str("imported!".into())
+        );
+        assert_eq!(
+            eval_ok("(builtins.import ./src/tests/import_tests/same-folder-import.nix).dataString"),
+            Value::Str("imported!".into())
+        );
+    }
+
+    #[test]
+    fn eval_child_folder_import() {
+        assert_eq!(
+            eval_ok("(builtins.import ./src/tests/import_tests/child-folder-import.nix).dataPath"),
+            Value::Str("imported!".into())
+        );
+        assert_eq!(
+            eval_ok(
+                "(builtins.import ./src/tests/import_tests/child-folder-import.nix).dataString"
+            ),
+            Value::Str("imported!".into())
+        );
+    }
+
+    #[test]
+    fn eval_parent_folder_import() {
+        assert_eq!(
+            eval_ok("(builtins.import ./src/tests/import_tests/nested/parent-folder-import.nix).dataPath"),
+            Value::Str("imported!".into())
+        );
+        assert_eq!(
+            eval_ok("(builtins.import ./src/tests/import_tests/nested/parent-folder-import.nix).dataString"),
+            Value::Str("imported!".into())
         );
     }
 

src/tests/import_tests/basic.nix

@@ -0,0 +1,3 @@
+{
+  data = "imported!";
+}

src/tests/import_tests/child-folder-import.nix

@@ -0,0 +1,4 @@
+{
+  dataPath = (builtins.import ./nested/basic.nix).data;
+  dataString = (builtins.import "./nested/basic.nix").data;
+}

src/tests/import_tests/nested/basic.nix

@@ -0,0 +1,3 @@
+{
+  data = "imported!";
+}

src/tests/import_tests/nested/parent-folder-import.nix

@@ -0,0 +1,4 @@
+{
+  dataPath = (builtins.import ../basic.nix).data;
+  dataString = (builtins.import "../basic.nix").data;
+}

src/tests/import_tests/same-folder-import.nix

@@ -0,0 +1,4 @@
+{
+  dataPath = (builtins.import ./basic.nix).data;
+  dataString = (builtins.import "./basic.nix").data;
+}