Prevent archive overwrite races

1 files changed, 18 insertions, 0 deletions

diff --git a/tests/archive.rs b/tests/archive.rs
index 6f803ef..6e59837 100644
--- a/tests/archive.rs
+++ b/tests/archive.rs
@@ -125,6 +125,24 @@ fn rejects_an_archive_output_inside_the_rootfs() {
 }
 
 #[test]
+fn refuses_to_replace_an_existing_archive() {
+    let fixture = tempdir().expect("fixture directory");
+    let rootfs = fixture.path().join("rootfs");
+    fs::create_dir(&rootfs).expect("create rootfs");
+    fs::write(rootfs.join("controller.conf"), "controller=true\n").expect("write rootfs file");
+    let artifact = fixture.path().join("controller.tar");
+    fs::write(&artifact, "existing artifact").expect("write existing artifact");
+
+    let error = NativeTarWriter::new()
+        .write(&rootfs, &artifact)
+        .expect_err("an existing archive must not be replaced");
+
+    assert!(error.to_string().contains("archive output already exists"));
+    assert_eq!(fs::read_to_string(&artifact).expect("read existing artifact"), "existing artifact");
+    assert!(!fixture.path().join("controller.tar.partial").exists());
+}
+
+#[test]
 fn removes_partial_output_when_an_unsupported_entry_stops_packaging() {
     let fixture = tempdir().expect("fixture directory");
     let rootfs = fixture.path().join("rootfs");