Add WIP resolve datatest harness

crates/frontend/fixtures/resolve/assumption_empty

@@ -0,0 +1 @@
+:-.

crates/frontend/src/lib.rs

@@ -45,7 +45,7 @@ pub mod prelude {
     pub use crate::{
         ast,
         diagnostic::{self, AccumulateDiagnostic},
-        editor,
+        editor, resolve,
         workspace::{self, AstNode, WithAst},
     };
 }

crates/frontend/tests/resolve.rs

@@ -0,0 +1,66 @@
+// Copyright (C) 2025-2026 Marceline Cramer
+// SPDX-License-Identifier: AGPL-3.0-or-later
+//
+// This file is part of Kerolox.
+//
+// Kerolox is free software: you can redistribute it and/or modify it under
+// the terms of the GNU Affero General Public License as published by the Free
+// Software Foundation, either version 3 of the License, or (at your option) any
+// later version.
+//
+// Kerolox is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+// FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for
+// more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with Kerolox. If not, see <https://www.gnu.org/licenses/>.
+
+use std::path::Path;
+
+use kerolox_frontend::{editor::Editor, prelude::*, workspace::Workspace};
+use salsa::DatabaseImpl as Db;
+
+datatest_stable::harness! {
+    { test = test_resolve, root = "fixtures/resolve/" },
+    { test = test_resolve, root = "../../examples/" },
+}
+
+fn test_resolve(path: &Path) -> datatest_stable::Result<()> {
+    // read test file to string
+    let src = std::fs::read_to_string(path).unwrap();
+
+    // create editor
+    let mut db = Db::new();
+    let files = Default::default();
+    let stdlib = Default::default();
+    let workspace = Workspace::new(&db, files, stdlib);
+    let path = std::path::absolute(path).unwrap();
+    let uri = lsp_types::Url::from_file_path(&path).unwrap();
+    let ed = Editor::new(&mut db, workspace, uri, &src);
+
+    // ensure tree-sitter has fully parsed
+    assert!(
+        !workspace::file_has_syntax_error(&db, ed.get_file()),
+        "test has syntax error"
+    );
+
+    // list, parse, and resolve top-level items
+    ast::items(&db, ed.get_file()).into_iter().for_each(|meta| {
+        use ast::Item::*;
+        match ast::item(&db, meta) {
+            Relation(item) => todo!(),
+            TypeAlias(item) => todo!(),
+            Import(item) => todo!(),
+            Rule(item) => {
+                resolve::rule(&db, item);
+            }
+            Assumption(item) => {
+                resolve::assumption(&db, item);
+            }
+        }
+    });
+
+    // all good
+    Ok(())
+}