test(gopher): assert orphan metadata is cleaned up

internal/protocol/gopher/gopher_test.go

@@ -437,6 +437,12 @@ func TestGopherResumeStaleMetadata(t *testing.T) {
 	if string(data) != "Fresh\n" {
 		t.Errorf("content = %q, want %q", string(data), "Fresh\n")
 	}
+	// The orphan sidecar from a different URL must be removed once the
+	// successful fresh download completes — otherwise stale metadata
+	// could be picked up by a future --resume run.
+	if output.FileExists(outPath + output.ResumeMetaFileSuffix) {
+		t.Error("expected orphan .goget.meta to be deleted after fresh download")
+	}
 }
 
 // TestGopherResumeIgnoredWhenWriterSet verifies that --resume is silently