better convert

projection/helpers_test.go

@@ -26,6 +26,10 @@ func os2Stat(path string) (os.FileInfo, error) {
 	return os.Stat(path)
 }
 
+func os2ReadFile(path string) ([]byte, error) {
+	return os.ReadFile(path)
+}
+
 // appendP appends a tProj keyed by its own SKU — the producer/test pattern over
 // the generic SnapshotWriter (Append takes an explicit key).
 func appendP(w *SnapshotWriter[tProj], p tProj) error {