tests: call stats() on specific implementation

This removes the remaining calls to `Index::stats()`.

lib/src/default_index_store.rs

@@ -678,6 +678,10 @@ impl MutableIndexImpl {
 }
 
 impl Index for MutableIndexImpl {
+    fn as_any(&self) -> &dyn Any {
+        self
+    }
+
     fn num_commits(&self) -> u32 {
         CompositeIndex(self).num_commits()
     }
@@ -1747,6 +1751,10 @@ impl ReadonlyIndexImpl {
 }
 
 impl Index for ReadonlyIndexImpl {
+    fn as_any(&self) -> &dyn Any {
+        self
+    }
+
     fn num_commits(&self) -> u32 {
         CompositeIndex(self).num_commits()
     }
@@ -1819,12 +1827,13 @@ mod tests {
     fn index_empty(on_disk: bool) {
         let temp_dir = testutils::new_temp_dir();
         let index = MutableIndexImpl::full(3, 16);
-        let index: Box<dyn Index> = if on_disk {
+        let index_segment: Box<dyn IndexSegment> = if on_disk {
             let saved_index = index.save_in(temp_dir.path().to_owned()).unwrap();
             Box::new(Arc::try_unwrap(saved_index).unwrap())
         } else {
             Box::new(index)
         };
+        let index = CompositeIndex(index_segment.as_ref());
 
         // Stats are as expected
         let stats = index.stats();
@@ -1849,12 +1858,13 @@ mod tests {
         let id_0 = CommitId::from_hex("000000");
         let change_id0 = new_change_id();
         index.add_commit_data(id_0.clone(), change_id0.clone(), &[]);
-        let index: Box<dyn Index> = if on_disk {
+        let index_segment: Box<dyn IndexSegment> = if on_disk {
             let saved_index = index.save_in(temp_dir.path().to_owned()).unwrap();
             Box::new(Arc::try_unwrap(saved_index).unwrap())
         } else {
             Box::new(index)
         };
+        let index = CompositeIndex(index_segment.as_ref());
 
         // Stats are as expected
         let stats = index.stats();
@@ -1930,12 +1940,13 @@ mod tests {
         index.add_commit_data(id_3.clone(), change_id3.clone(), &[id_2.clone()]);
         index.add_commit_data(id_4.clone(), change_id4, &[id_1.clone()]);
         index.add_commit_data(id_5.clone(), change_id5, &[id_4.clone(), id_2.clone()]);
-        let index: Box<dyn Index> = if on_disk {
+        let index_segment: Box<dyn IndexSegment> = if on_disk {
             let saved_index = index.save_in(temp_dir.path().to_owned()).unwrap();
             Box::new(Arc::try_unwrap(saved_index).unwrap())
         } else {
             Box::new(index)
         };
+        let index = CompositeIndex(index_segment.as_ref());
 
         // Stats are as expected
         let stats = index.stats();
@@ -2020,12 +2031,13 @@ mod tests {
             new_change_id(),
             &[id_1, id_2, id_3, id_4, id_5],
         );
-        let index: Box<dyn Index> = if on_disk {
+        let index_segment: Box<dyn IndexSegment> = if on_disk {
             let saved_index = index.save_in(temp_dir.path().to_owned()).unwrap();
             Box::new(Arc::try_unwrap(saved_index).unwrap())
         } else {
             Box::new(index)
         };
+        let index = CompositeIndex(index_segment.as_ref());
 
         // Stats are as expected
         let stats = index.stats();

lib/src/index.rs

@@ -46,6 +46,8 @@ pub trait IndexStore: Send + Sync + Debug {
 }
 
 pub trait Index {
+    fn as_any(&self) -> &dyn Any;
+
     fn num_commits(&self) -> u32;
 
     fn stats(&self) -> IndexStats;

lib/tests/test_index.rs

@@ -17,6 +17,7 @@ use std::sync::Arc;
 use jujutsu_lib::backend::CommitId;
 use jujutsu_lib::commit::Commit;
 use jujutsu_lib::commit_builder::CommitBuilder;
+use jujutsu_lib::default_index_store::ReadonlyIndexImpl;
 use jujutsu_lib::index::Index;
 use jujutsu_lib::repo::{MutableRepo, ReadonlyRepo, Repo};
 use jujutsu_lib::settings::UserSettings;
@@ -86,7 +87,7 @@ fn test_index_commits_standard_cases(use_git: bool) {
     let commit_h = graph_builder.commit_with_parents(&[&commit_e]);
     let repo = tx.commit();
 
-    let index = repo.index();
+    let index = as_index_impl(&repo);
     // There should be the root commit, plus 8 more
     assert_eq!(index.num_commits(), 1 + 8);
 
@@ -146,7 +147,7 @@ fn test_index_commits_criss_cross(use_git: bool) {
     }
     let repo = tx.commit();
 
-    let index = repo.index();
+    let index = as_index_impl(&repo);
     // There should the root commit, plus 2 for each generation
     assert_eq!(index.num_commits(), 1 + 2 * (num_generations as u32));
 
@@ -292,7 +293,7 @@ fn test_index_commits_previous_operations(use_git: bool) {
     std::fs::create_dir(&index_operations_dir).unwrap();
 
     let repo = load_repo_at_head(&settings, repo.repo_path());
-    let index = repo.index();
+    let index = as_index_impl(&repo);
     // There should be the root commit, plus 3 more
     assert_eq!(index.num_commits(), 1 + 3);
 
@@ -343,7 +344,7 @@ fn test_index_commits_incremental(use_git: bool) {
     tx.commit();
 
     let repo = load_repo_at_head(&settings, repo.repo_path());
-    let index = repo.index();
+    let index = as_index_impl(&repo);
     // There should be the root commit, plus 3 more
     assert_eq!(index.num_commits(), 1 + 3);
 
@@ -388,7 +389,7 @@ fn test_index_commits_incremental_empty_transaction(use_git: bool) {
     repo.start_transaction(&settings, "test").commit();
 
     let repo = load_repo_at_head(&settings, repo.repo_path());
-    let index = repo.index();
+    let index = as_index_impl(&repo);
     // There should be the root commit, plus 1 more
     assert_eq!(index.num_commits(), 1 + 1);
 
@@ -445,8 +446,16 @@ fn create_n_commits(
     tx.commit()
 }
 
+fn as_index_impl(repo: &Arc<ReadonlyRepo>) -> &ReadonlyIndexImpl {
+    repo.readonly_index()
+        .as_index()
+        .as_any()
+        .downcast_ref::<ReadonlyIndexImpl>()
+        .unwrap()
+}
+
 fn commits_by_level(repo: &Arc<ReadonlyRepo>) -> Vec<u32> {
-    repo.index()
+    as_index_impl(repo)
         .stats()
         .levels
         .iter()