Protect companion manifests from overwrite

1 files changed, 15 insertions, 0 deletions

diff --git a/tests/compare.rs b/tests/compare.rs
index f7b3a04..4f48721 100644
--- a/tests/compare.rs
+++ b/tests/compare.rs
@@ -159,6 +159,21 @@ fn writes_distinct_manifests_for_artifacts_in_the_same_directory() {
 }
 
 #[test]
+fn refuses_to_overwrite_an_existing_companion_manifest() {
+    let fixture = tempdir().expect("temporary directory");
+    let artifact = fixture.path().join("controller.tar");
+    let manifest_path = ArtifactManifest::path_beside(&artifact).expect("manifest path");
+    fs::write(&manifest_path, "preserve this manifest").expect("write existing manifest");
+
+    let error = baseline()
+        .write_beside(&artifact)
+        .expect_err("existing companion manifests must not be overwritten");
+
+    assert!(error.to_string().contains("create artifact manifest"));
+    assert_eq!(fs::read_to_string(&manifest_path).expect("read existing manifest"), "preserve this manifest");
+}
+
+#[test]
 fn rejects_duplicate_semantic_keys() {
     let error = ArtifactManifest::new(
         vec![PackageRecord::new("controller", "1"), PackageRecord::new("controller", "2")],