Introduce ra_db::fixture fixture module

The goal here is to share more testing infrastructure between crates.

crates/ra_hir_def/src/lib.rs

@@ -15,6 +15,9 @@ pub mod builtin_type;
 pub mod adt;
 pub mod diagnostics;
 
+#[cfg(test)]
+mod test_db;
+
 // FIXME: this should be private
 pub mod nameres;
 

crates/ra_hir_def/src/nameres/collector.rs

@@ -739,17 +739,18 @@ fn is_macro_rules(path: &Path) -> bool {
     path.as_ident() == Some(&name::MACRO_RULES)
 }
 
-#[cfg(never)]
+#[cfg(test)]
 mod tests {
-    use ra_db::SourceDatabase;
-
-    use super::*;
-    use crate::{db::DefDatabase, mock::MockDatabase, Crate};
     use ra_arena::Arena;
+    use ra_db::{fixture::WithFixture, SourceDatabase};
     use rustc_hash::FxHashSet;
 
+    use crate::{db::DefDatabase2, test_db::TestDB};
+
+    use super::*;
+
     fn do_collect_defs(
-        db: &impl DefDatabase,
+        db: &impl DefDatabase2,
         def_map: CrateDefMap,
         monitor: MacroStackMonitor,
     ) -> CrateDefMap {
@@ -768,12 +769,11 @@ mod tests {
     }
 
     fn do_limited_resolve(code: &str, limit: u32, poison_limit: u32) -> CrateDefMap {
-        let (db, _source_root, _) = MockDatabase::with_single_file(&code);
-        let crate_id = db.crate_graph().iter().next().unwrap();
-        let krate = Crate { crate_id };
+        let (db, _file_id) = TestDB::with_single_file(&code);
+        let krate = db.crate_graph().iter().next().unwrap();
 
         let def_map = {
-            let edition = krate.edition(&db);
+            let edition = db.crate_graph().edition(krate);
             let mut modules: Arena<CrateModuleId, ModuleData> = Arena::default();
             let root = modules.alloc(ModuleData::default());
             CrateDefMap {

crates/ra_hir_def/src/test_db.rs

@@ -0,0 +1,40 @@
+use std::{panic, sync::Arc};
+
+use ra_db::{salsa, CrateId, FileId, FileLoader, FileLoaderDelegate};
+use relative_path::RelativePath;
+
+#[salsa::database(
+    ra_db::SourceDatabaseExtStorage,
+    ra_db::SourceDatabaseStorage,
+    hir_expand::db::AstDatabaseStorage,
+    crate::db::InternDatabaseStorage,
+    crate::db::DefDatabase2Storage
+)]
+#[derive(Debug, Default)]
+pub struct TestDB {
+    runtime: salsa::Runtime<TestDB>,
+}
+
+impl salsa::Database for TestDB {
+    fn salsa_runtime(&self) -> &salsa::Runtime<Self> {
+        &self.runtime
+    }
+}
+
+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_relative_path(
+        &self,
+        anchor: FileId,
+        relative_path: &RelativePath,
+    ) -> Option<FileId> {
+        FileLoaderDelegate(self).resolve_relative_path(anchor, relative_path)
+    }
+    fn relevant_crates(&self, file_id: FileId) -> Arc<Vec<CrateId>> {
+        FileLoaderDelegate(self).relevant_crates(file_id)
+    }
+}