1 files changed, 49 insertions, 0 deletions

diff --git a/crates/hir_expand/src/test_db.rs b/crates/hir_expand/src/test_db.rs
new file mode 100644
index 000000000..86a5d867e
--- /dev/null
+++ b/crates/hir_expand/src/test_db.rs
@@ -0,0 +1,49 @@
+//! Database used for testing `hir_expand`.
+
+use std::{
+    fmt, panic,
+    sync::{Arc, Mutex},
+};
+
+use base_db::{salsa, CrateId, FileId, FileLoader, FileLoaderDelegate};
+use rustc_hash::FxHashSet;
+
+#[salsa::database(
+    base_db::SourceDatabaseExtStorage,
+    base_db::SourceDatabaseStorage,
+    crate::db::AstDatabaseStorage
+)]
+#[derive(Default)]
+pub struct TestDB {
+    storage: salsa::Storage<TestDB>,
+    events: Mutex<Option<Vec<salsa::Event>>>,
+}
+
+impl fmt::Debug for TestDB {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("TestDB").finish()
+    }
+}
+
+impl salsa::Database for TestDB {
+    fn salsa_event(&self, event: salsa::Event) {
+        let mut events = self.events.lock().unwrap();
+        if let Some(events) = &mut *events {
+            events.push(event);
+        }
+    }
+}
+
+impl panic::RefUnwindSafe for TestDB {}
+
+impl FileLoader for TestDB {
+    fn file_text(&self, file_id: FileId) -> Arc<String> {
+        FileLoaderDelegate(self).file_text(file_id)
+    }
+    fn resolve_path(&self, anchor: FileId, path: &str) -> Option<FileId> {
+        FileLoaderDelegate(self).resolve_path(anchor, path)
+    }
+    fn relevant_crates(&self, file_id: FileId) -> Arc<FxHashSet<CrateId>> {
+        FileLoaderDelegate(self).relevant_crates(file_id)
+    }
+}