refactor

- add object-hash test
- add env variable docs
- remove seemingly unnecessary fixture hash setup.

Co-authored-by: chatgpt-codex-connector[bot] <199175422+chatgpt-codex-connector[bot]@users.noreply.github.com>

Author: Byron

gix-commitgraph/tests/commitgraph.rs

@@ -81,6 +81,14 @@ pub fn graph_and_expected_named(
     let expected = inspect_refs(&repo_dir, refs);
     let cg =
         Graph::from_info_dir(&repo_dir.join(".git").join("objects").join("info")).expect("graph present and valid");
+    let object_hash = cg.object_hash();
+    if let Some(any_ref) = expected.values().next() {
+        assert_eq!(
+            object_hash,
+            any_ref.id().kind(),
+            "graph hash kind should match fixture object IDs"
+        );
+    }
     (cg, expected)
 }
 

justfile

@@ -155,8 +155,8 @@ unit-tests:
     cargo nextest run -p gix-archive --no-default-features --features tar_gz --no-fail-fast
     cargo nextest run -p gix-archive --no-default-features --features zip --no-fail-fast
     cargo nextest run -p gix-status-tests --features gix-features-parallel --no-fail-fast
-    env GIX_TEST_FIXTURE_HASH=sha1 cargo nextest run -p gix-worktree-state-tests --features gix-features-parallel --no-fail-fast
-    env GIX_TEST_FIXTURE_HASH=sha1 cargo nextest run -p gix-worktree-tests --features gix-features-parallel --no-fail-fast
+    cargo nextest run -p gix-worktree-state-tests --features gix-features-parallel --no-fail-fast
+    cargo nextest run -p gix-worktree-tests --features gix-features-parallel --no-fail-fast
     cargo nextest run -p gix-error --no-fail-fast --test auto-chain-error --features auto-chain-error
     cargo nextest run -p gix-error --no-fail-fast
     cargo nextest run -p gix-hash --no-fail-fast
@@ -175,7 +175,7 @@ unit-tests:
     env GIX_TEST_FIXTURE_HASH=sha256 cargo nextest run -p gix-pack --all-features --no-fail-fast
     cargo nextest run -p gix-pack-tests --features all-features --no-fail-fast
     cargo nextest run -p gix-pack-tests --features gix-features-parallel --no-fail-fast
-    env GIX_TEST_FIXTURE_HASH=sha1 cargo nextest run -p gix-index-tests --features gix-features-parallel --no-fail-fast
+    cargo nextest run -p gix-index-tests --features gix-features-parallel --no-fail-fast
     cargo nextest run -p gix-packetline --features blocking-io,maybe-async/is_sync --test blocking-packetline --no-fail-fast
     cargo nextest run -p gix-packetline --features async-io --test async-packetline --no-fail-fast
     cargo nextest run -p gix-transport --features http-client-curl,maybe-async/is_sync --no-fail-fast

tests/tools/src/lib.rs

@@ -1,5 +1,14 @@
 //! Utilities for testing `gitoxide` crates, many of which might be useful for testing programs that use `git` in general.
 //!
+//! ## Environment Variables
+//!
+//! ### `GIX_TEST_FIXTURE_HASH`
+//!
+//! Set this variable to control which hash function is used when creating or loading test fixtures.
+//! Valid values are the names of hash functions supported by `gix_hash::Kind` (e.g., `sha1`, `sha256`).
+//! If not set, the default hash function via `gix_hash::Kind::default()` is used.
+//!
+
 //! ## Feature Flags
 #![cfg_attr(
     all(doc, feature = "document-features"),