Switch to test-fork for relative path tests

We have tests that check that handling of relative paths works as it
should. These tests need to modify the process' current working
directory, which is global state and can conceivably cause conflicts.
Make sure to run these tests in a separate process by harnessing the
test-fork crate.

Author: d-e-s-o

Cargo.lock

@@ -46,8 +46,8 @@ tracing-subscriber = {version = "0.3", default-features = false, features = ["an
 warp = {version = "0.3", default-features = false}
 
 [dev-dependencies]
-pathdiff = "0.2"
-tempfile = {version = "3.1"}
+tempfile = "3.1"
+test-fork = "0.1.3"
 tokio = {version = "1.34", default-features = false, features = ["macros", "rt"]}
 
 # A set of unused dependencies that we require to force correct minimum

Cargo.toml

@@ -1,4 +1,4 @@
-// Copyright (C) 2020-2024 The cargo-http-registry Developers
+// Copyright (C) 2020-2025 The cargo-http-registry Developers
 // SPDX-License-Identifier: GPL-3.0-or-later
 
 use std::collections::BTreeMap;
@@ -395,6 +395,8 @@ mod tests {
 
   use tempfile::tempdir;
 
+  use test_fork::fork;
+
 
   #[test]
   fn url_port_parsing() {
@@ -488,15 +490,19 @@ mod tests {
   }
 
   /// Ensure we can use some special names as relative index root.
+  ///
+  /// Needs to run in separate process because it changes the working
+  /// directory.
+  #[fork]
   #[test]
   fn index_root_relative_path() {
     let base = tempdir().unwrap();
-    env::set_current_dir(&base).unwrap();
+    let () = env::set_current_dir(&base).unwrap();
     let addr = "127.0.0.1:0".parse().unwrap();
 
     for special_name in ["config.json", "index"] {
       let relative_index_root = Path::new(special_name);
-      create_dir_all(relative_index_root).unwrap();
+      let () = create_dir_all(relative_index_root).unwrap();
 
       let index = Index::new(relative_index_root, &addr).unwrap();
       // The repository should be clean.

src/index.rs

@@ -15,11 +15,14 @@ use std::process::Command;
 use anyhow::bail;
 use anyhow::Context as _;
 use anyhow::Result;
-use pathdiff::diff_paths;
+
 use tempfile::tempdir;
 
+use test_fork::fork;
+
 use tokio::spawn;
 use tokio::task::JoinHandle;
+use tokio::test;
 
 use cargo_http_registry::serve;
 
@@ -167,11 +170,20 @@ where
 
 
 /// Serve our registry.
+///
+/// # Notes
+/// When invoked with `RegistryRootPath::Relative` this function changes
+/// the process' current working directory.
 fn serve_registry(root_path: RegistryRootPath) -> (JoinHandle<()>, PathBuf, SocketAddr) {
   let root = tempdir().unwrap();
   let path = match root_path {
     RegistryRootPath::Absolute => root.path().to_owned(),
-    RegistryRootPath::Relative => diff_paths(root.path(), env::current_dir().unwrap()).unwrap(),
+    RegistryRootPath::Relative => {
+      let base_dir = root.path().parent().unwrap();
+      let () = env::set_current_dir(base_dir).unwrap();
+      let index_dir = root.path().file_name().unwrap();
+      PathBuf::from(index_dir)
+    },
   };
   let addr = "127.0.0.1:0".parse().unwrap();
 
@@ -189,7 +201,11 @@ fn serve_registry(root_path: RegistryRootPath) -> (JoinHandle<()>, PathBuf, Sock
 
 
 /// Check that we can publish a crate.
-#[tokio::test]
+///
+/// Needs to run in separate process because it changes the working
+/// directory.
+#[test]
+#[fork]
 async fn publish() {
   async fn test(root_path: RegistryRootPath) {
     let (_handle, _reg_root, addr) = serve_registry(root_path);
@@ -220,7 +236,7 @@ async fn publish() {
 
 
 /// Check that we can publish crates with a renamed dependency.
-#[tokio::test]
+#[test]
 async fn publish_renamed() {
   let (_handle, _reg_root, addr) = serve_registry(RegistryRootPath::Absolute);
 
@@ -319,15 +335,15 @@ async fn test_publish_and_consume(registry_locator: Locator) {
 
 
 /// Check that we can consume a published crate over HTTP.
-#[tokio::test]
+#[test]
 async fn get_http() {
   let (_handle, _, addr) = serve_registry(RegistryRootPath::Absolute);
   test_publish_and_consume(Locator::Socket(addr)).await
 }
 
 
 /// Check that we can consume a published crate through the file system.
-#[tokio::test]
+#[test]
 async fn get_filesystem() {
   let (_handle, root, _) = serve_registry(RegistryRootPath::Absolute);
   test_publish_and_consume(Locator::Path(root)).await