first test for simple file modification detection (#470)

git-repository/tests/object/commit.rs

@@ -0,0 +1,36 @@
+use std::cmp::Ordering;
+
+use git_testtools::hex_to_id;
+
+use crate::basic_repo;
+
+#[test]
+fn short_id() -> crate::Result {
+    let repo = basic_repo()?;
+    let commit = repo.head_commit()?;
+    assert_eq!(commit.short_id()?.cmp_oid(&commit.id), Ordering::Equal);
+    Ok(())
+}
+
+#[test]
+fn tree() -> crate::Result {
+    let repo = basic_repo()?;
+    let commit = repo.head_commit()?;
+
+    assert_eq!(commit.tree()?.id, commit.tree_id().expect("id present"));
+    assert_eq!(
+        commit.tree_id().ok().map(|id| id.detach()),
+        Some(hex_to_id("21d3ba9a26b790a4858d67754ae05d04dfce4d0c"))
+    );
+    Ok(())
+}
+
+#[test]
+fn decode() -> crate::Result {
+    let repo = basic_repo()?;
+    let commit = repo.head_commit()?;
+    assert_eq!(commit.decode()?.message, commit.message_raw()?);
+    assert_eq!(commit.decode()?.message(), commit.message()?);
+    assert_eq!(commit.decode()?.message, "c2\n");
+    Ok(())
+}

git-repository/tests/object/mod.rs

@@ -1,41 +1,5 @@
-mod commit {
-    use std::cmp::Ordering;
-
-    use git_testtools::hex_to_id;
-
-    use crate::basic_repo;
-
-    #[test]
-    fn short_id() -> crate::Result {
-        let repo = basic_repo()?;
-        let commit = repo.head_commit()?;
-        assert_eq!(commit.short_id()?.cmp_oid(&commit.id), Ordering::Equal);
-        Ok(())
-    }
-
-    #[test]
-    fn tree() -> crate::Result {
-        let repo = basic_repo()?;
-        let commit = repo.head_commit()?;
-
-        assert_eq!(commit.tree()?.id, commit.tree_id().expect("id present"));
-        assert_eq!(
-            commit.tree_id().ok().map(|id| id.detach()),
-            Some(hex_to_id("21d3ba9a26b790a4858d67754ae05d04dfce4d0c"))
-        );
-        Ok(())
-    }
-
-    #[test]
-    fn decode() -> crate::Result {
-        let repo = basic_repo()?;
-        let commit = repo.head_commit()?;
-        assert_eq!(commit.decode()?.message, commit.message_raw()?);
-        assert_eq!(commit.decode()?.message(), commit.message()?);
-        assert_eq!(commit.decode()?.message, "c2\n");
-        Ok(())
-    }
-}
+mod commit;
+mod tree;
 
 #[test]
 fn object_ref_size_in_memory() {

git-repository/tests/object/tree.rs

@@ -0,0 +1,44 @@
+mod diff {
+    use crate::remote;
+    use git_object::bstr::ByteSlice;
+    use git_object::tree::EntryMode;
+    use git_repository as git;
+    use git_repository::object::tree::diff::Event;
+    use std::convert::Infallible;
+
+    #[test]
+    fn changes_against_tree_modified() {
+        let repo = remote::repo("base");
+        let from = tree_named(&repo, "g");
+        let to = tree_named(&repo, "h");
+        from.changes()
+            .for_each_to_obtain_tree(&to, |event| -> Result<_, Infallible> {
+                match event {
+                    Event::Modification {
+                        previous_entry_mode,
+                        previous_id,
+                        entry_mode,
+                        id,
+                    } => {
+                        assert_eq!(previous_entry_mode, EntryMode::Blob);
+                        assert_eq!(entry_mode, EntryMode::Blob);
+                        assert_eq!(previous_id.object().unwrap().data.as_bstr(), "g\n");
+                        assert_eq!(id.object().unwrap().data.as_bstr(), "h\n");
+                        Ok(git::diff::tree::visit::Action::Continue)
+                    }
+                    Event::Deletion { .. } | Event::Addition { .. } => unreachable!("only modification is expected"),
+                }
+            })
+            .unwrap();
+    }
+
+    fn tree_named<'repo>(repo: &'repo git::Repository, rev_spec: &str) -> git::Tree<'repo> {
+        repo.rev_parse_single(rev_spec)
+            .unwrap()
+            .object()
+            .unwrap()
+            .peel_to_kind(git::object::Kind::Tree)
+            .unwrap()
+            .into_tree()
+    }
+}