feat: add Rust closure fixtures to gix-testtools by Copilot · Pull Request #2412 · GitoxideLabs/gitoxide

Copilot · 2026-02-04T03:28:00Z

Adds ability to create fixtures using Rust closures instead of shell scripts, with manual version numbers for cache invalidation.

New API

rust_fixture_read_only(name, version, closure) - cached read-only fixture
rust_fixture_writable(name, version, mode, closure) - writable temp directory copy
*_standalone variants for fixtures/ instead of tests/fixtures/

Implementation

Version number (u32) replaces CRC-based script identity for cache invalidation
Archives prefixed with rust- (e.g., rust-my_fixture.tar.xz)
Reuses existing locking, archive extraction, and failure marker infrastructure

Example

let dir = gix_testtools::rust_fixture_read_only("my_fixture", 1, |dir| {
    std::fs::write(dir.join("file.txt"), "content")?;
    Ok(())
})?;

Increment version when closure behavior changes to force cache rebuild.

Original prompt

Add a way to execute Rust closures on a given directory in the gix-testtools crate, fully integrated into the existing ways of creating fixtures with scripts. The key here is to let the caller provide a version number (simple integer), that needs to be incremented manually to allow caching.
With it, it should be possible to make a fixture something like this:
let dir = gix_testtools::rust_fixture_read_only(1, |dir| { …create the fixture in Rust here })?;

💬 We'd love your input! Share your thoughts on Copilot coding agent in our 2 minute survey.

…to gix-testtools Co-authored-by: Byron <63622+Byron@users.noreply.github.com>

Reviewed-by: Claude <noreply@anthropic.com>

Copilot

Pull request overview

Adds Rust-closure-driven fixture generation to gix-testtools, integrating with the existing cached fixture/archive system while switching cache invalidation to a caller-supplied version integer.

Changes:

Introduce rust_fixture_read_only* and rust_fixture_writable* APIs, with version: u32 used as the cache/archive identity.
Refactor fixture generation to reuse shared marker/failure/archive handling and centralize tar extension selection.
Add tests for Rust fixture caching, version invalidation, error propagation, and standalone fixture roots; move existing unit tests into a dedicated test module file.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 5 comments.

File	Description
`tests/tools/src/lib.rs`	Adds new Rust fixture APIs; factors out common “run generator + marker/archive handling”; adds `tar_extension()` and externalizes unit tests module.
`tests/tools/tests/rust_fixture.rs`	New integration tests validating Rust fixture behaviors (cache hit, version bump, writable mode, error propagation, standalone root).
`tests/tools/src/tests.rs`	New internal unit test module extracted from `lib.rs`.
`tests/tools/.gitignore`	Adds ignore rule for the standalone `fixtures/` directory.

tests/tools/src/lib.rs

Copilot · 2026-02-04T08:35:57Z

tests/tools/tests/rust_fixture.rs

+    let dir_str = dir.to_string_lossy();
+    assert!(
+        dir_str.contains("fixtures") && dir_str.contains("generated-do-not-edit"),
+        "Standalone fixture should be in fixtures/generated-do-not-edit directory, got: {dir_str}"
+    );
+    assert!(
+        !dir_str.contains("tests/fixtures"),
+        "Standalone fixture should NOT be in tests/fixtures directory, got: {dir_str}"


This path assertion is string-based and assumes / separators. On Windows, a wrong path like tests\\fixtures\\... would still satisfy the positive check and the negative "tests/fixtures" check would not catch it. Prefer checking path components via Path APIs (e.g., starts_with("fixtures") and !starts_with("tests")) to make the test platform-correct.

Suggested change

let dir_str = dir.to_string_lossy();

assert!(

dir_str.contains("fixtures") && dir_str.contains("generated-do-not-edit"),

"Standalone fixture should be in fixtures/generated-do-not-edit directory, got: {dir_str}"

);

assert!(

!dir_str.contains("tests/fixtures"),

"Standalone fixture should NOT be in tests/fixtures directory, got: {dir_str}"

let components: Vec<_> = dir.components().collect();

let has_fixtures = components.iter().any(|c| c.as_os_str() == "fixtures");

let has_generated = components

.iter()

.any(|c| c.as_os_str() == "generated-do-not-edit");

assert!(

has_fixtures && has_generated,

"Standalone fixture should be in fixtures/generated-do-not-edit directory, got: {}",

dir.display()

);

let has_tests_fixtures = components

.windows(2)

.any(|pair| pair[0].as_os_str() == "tests" && pair[1].as_os_str() == "fixtures");

assert!(

!has_tests_fixtures,

"Standalone fixture should NOT be in tests/fixtures directory, got: {}",

dir.display()

Copilot · 2026-02-04T08:35:58Z

tests/tools/.gitignore

@@ -0,0 +1 @@
+fixtures/


With the new integration-style rust fixture tests, running this crate’s tests will also generate tests/fixtures/generated-archives/*, which isn’t covered by this ignore entry and may leave untracked archives in the working tree. Consider narrowing the ignore to generated fixture outputs and/or adding an ignore entry for tests/fixtures/generated-archives/ (or a pattern matching *.tar/*.tar.xz) to keep local worktrees clean.

tests/tools/src/tests.rs

Copilot AI assigned Copilot and Byron Feb 4, 2026

Copilot started work on behalf of Byron February 4, 2026 03:28 View session

Copilot AI changed the title ~~[WIP] Add execution of Rust closures in gix-testtools~~ feat: add Rust closure fixtures to gix-testtools Feb 4, 2026

Copilot finished work on behalf of Byron February 4, 2026 03:39

Copilot AI requested a review from Byron February 4, 2026 03:39

feat: add rust_fixture_read_only and rust_fixture_writable functions …

501da55

…to gix-testtools Co-authored-by: Byron <63622+Byron@users.noreply.github.com>

Byron force-pushed the copilot/add-execute-rust-closures-again branch 2 times, most recently from 748fa15 to a0d9d91 Compare February 4, 2026 06:12

loci-dev mentioned this pull request Feb 4, 2026

UPSTREAM PR #2412: feat: add Rust closure fixtures to gix-testtools auroralabs-loci/gitoxide#18

Open

Byron added 2 commits February 4, 2026 09:25

refactor

ab33ceb

Deduplicate testtools marker implementation

fff844b

Reviewed-by: Claude <noreply@anthropic.com>

Byron force-pushed the copilot/add-execute-rust-closures-again branch from a0d9d91 to fff844b Compare February 4, 2026 08:26

Byron requested a review from Copilot February 4, 2026 08:27

Copilot started reviewing on behalf of Byron February 4, 2026 08:27 View session

Copilot AI reviewed Feb 4, 2026

View reviewed changes

Byron marked this pull request as ready for review February 4, 2026 08:50

Address Copilot review

b63bf6f

Byron enabled auto-merge February 4, 2026 08:53

Byron merged commit 675ce68 into main Feb 4, 2026
30 checks passed

cruessler mentioned this pull request Feb 7, 2026

Add GIX_TEST_FIXTURE_HASH to gix-testtools #2377

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feat: add Rust closure fixtures to gix-testtools#2412

feat: add Rust closure fixtures to gix-testtools#2412
Byron merged 4 commits intomainfrom
copilot/add-execute-rust-closures-again

Copilot AI commented Feb 4, 2026 •

edited

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-    let dir_str = dir.to_string_lossy();
-    assert!(
-        dir_str.contains("fixtures") && dir_str.contains("generated-do-not-edit"),
-        "Standalone fixture should be in fixtures/generated-do-not-edit directory, got: {dir_str}"
-    );
-    assert!(
-        !dir_str.contains("tests/fixtures"),
-        "Standalone fixture should NOT be in tests/fixtures directory, got: {dir_str}"
+    let components: Vec<_> = dir.components().collect();
+    let has_fixtures = components.iter().any(|c| c.as_os_str() == "fixtures");
+    let has_generated = components
+        .iter()
+        .any(|c| c.as_os_str() == "generated-do-not-edit");
+    assert!(
+        has_fixtures && has_generated,
+        "Standalone fixture should be in fixtures/generated-do-not-edit directory, got: {}",
+        dir.display()
+    );
+    let has_tests_fixtures = components
+        .windows(2)
+        .any(|pair| pair[0].as_os_str() == "tests" && pair[1].as_os_str() == "fixtures");
+    assert!(
+        !has_tests_fixtures,
+        "Standalone fixture should NOT be in tests/fixtures directory, got: {}",
+        dir.display()

		@@ -0,0 +1 @@
		fixtures/

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Copilot AI commented Feb 4, 2026 •

edited

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