test(e2e): enforce external client prerequisites (#6402)

crates/e2e_test/src/common.rs

@@ -494,15 +494,20 @@ fn awscurl_binary_path() -> PathBuf {
         .unwrap_or_else(|| PathBuf::from("awscurl"))
 }
 
-pub fn awscurl_available() -> bool {
-    let path = awscurl_binary_path();
-    if path.components().count() > 1 || path.is_absolute() {
-        return path.is_file();
+fn verify_awscurl_path(path: &Path) -> std::io::Result<()> {
+    let output = Command::new(path).arg("--help").output()?;
+    if output.status.success() {
+        return Ok(());
     }
 
-    std::env::var_os("PATH")
-        .map(|paths| std::env::split_paths(&paths).any(|dir| dir.join(&path).is_file()))
-        .unwrap_or(false)
+    Err(std::io::Error::other(format!(
+        "awscurl prerequisite check failed: {}",
+        String::from_utf8_lossy(&output.stderr).trim()
+    )))
+}
+
+pub fn require_awscurl() -> std::io::Result<()> {
+    verify_awscurl_path(&awscurl_binary_path())
 }
 
 // Global initialization
@@ -1747,6 +1752,22 @@ mod tests {
         assert_eq!(normalize_rustfs_build_features(" , "), None);
     }
 
+    #[test]
+    fn missing_awscurl_is_a_prerequisite_failure() {
+        let missing = std::env::temp_dir().join(format!("missing-awscurl-{}", Uuid::new_v4()));
+
+        let error = verify_awscurl_path(&missing).expect_err("a missing awscurl binary must fail the test prerequisite");
+
+        assert_eq!(error.kind(), ErrorKind::NotFound);
+    }
+
+    #[test]
+    fn available_awscurl_client_passes_prerequisite_check() {
+        let executable = std::env::current_exe().expect("the test executable should have a path");
+
+        verify_awscurl_path(&executable).expect("an available client with a working help command should pass");
+    }
+
     #[test]
     fn capture_log_path_uses_temp_directory_basename() {
         assert_eq!(