Add error checking to git test system calls

Co-authored-by: jackfirth <[email protected]>

Author: Copilot

private/file-group.rkt

@@ -222,14 +222,19 @@
     (test-case "file-group-resolve with git repository"
       (define test-dir (make-temporary-file "resyntax-test-git-~a" 'directory))
       (parameterize ([current-directory test-dir])
-        (system "git init -q")
-        (system "git config user.email '[email protected]'")
-        (system "git config user.name 'Test User'")
+        (unless (system "git init -q")
+          (fail "git init failed"))
+        (unless (system "git config user.email '[email protected]'")
+          (fail "git config email failed"))
+        (unless (system "git config user.name 'Test User'")
+          (fail "git config name failed"))
         (define test-file (build-path test-dir "test.rkt"))
         (call-with-output-file test-file
           (λ (out) (displayln "#lang racket/base\n(void)" out)))
-        (system "git add test.rkt")
-        (system "git commit -q -m 'Initial commit'")
+        (unless (system "git add test.rkt")
+          (fail "git add failed"))
+        (unless (system "git commit -q -m 'Initial commit'")
+          (fail "git commit failed"))
         (call-with-output-file test-file #:exists 'append
           (λ (out) (displayln "(define x 1)" out)))
         (define group (git-repository-file-group test-dir "HEAD"))