wip

tests/Fixtures/Tia/GitRepo.php

@@ -96,6 +96,17 @@ final readonly class GitRepo
         $this->run(['symbolic-ref', 'refs/remotes/origin/HEAD', 'refs/remotes/origin/'.$branch]);
     }
 
+    /**
+     * Drops `refs/remotes/origin/HEAD` while keeping the remote-tracking branch
+     * — what a CI checkout looks like. `actions/checkout` builds its working
+     * copy with `git init` plus a single-ref `fetch` rather than a `clone`, and
+     * only a `clone` writes that symbolic ref.
+     */
+    public function unsetOriginHead(): void
+    {
+        $this->run(['symbolic-ref', '--delete', 'refs/remotes/origin/HEAD']);
+    }
+
     public function config(string $key, string $value): void
     {
         $this->run(['config', '--local', $key, $value]);

tests/Fixtures/Tia/Project.php

@@ -222,6 +222,13 @@ final class Project
                 'PARATEST' => '0',
                 'PAO_DISABLE' => '1',
                 'HOME' => $this->home(),
+                // Blanked for the same reason `GitRepo::ENV` blanks git's own
+                // config: the default branch a CI provider reports is the one
+                // *its* build is for. Pest's suite runs on GitHub Actions, so
+                // without this every scenario would autodetect Pest's default
+                // branch instead of the fixture's.
+                'GITHUB_EVENT_PATH' => '',
+                'CI_DEFAULT_BRANCH' => '',
                 ...$environment,
             ],
         );