Harden debug bundle filesystem collaborators

internal/framework/debug/recorder_test.go

@@ -1,9 +1,13 @@
 package debug
 
 import (
+	"fmt"
 	"os"
 	"path/filepath"
+	"sync"
 	"testing"
+
+	"gitea.maximumdirect.net/eric/notarius/internal/framework/pipeline"
 )
 
 func TestFilesystemRecorderWritesWithinTraceRoot(t *testing.T) {
@@ -26,3 +30,50 @@ func TestFilesystemRecorderWritesWithinTraceRoot(t *testing.T) {
 		t.Fatal("accepted traversal")
 	}
 }
+
+func TestFilesystemRecorderPropagatesWriteFailures(t *testing.T) {
+	root := filepath.Join(t.TempDir(), "trace")
+	if err := os.WriteFile(root, []byte("not a directory"), 0o600); err != nil {
+		t.Fatal(err)
+	}
+	recorder, err := NewFilesystemRecorder(root)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err := recorder.WriteBytes("attempt/data", []byte("payload")); err == nil {
+		t.Fatal("WriteBytes concealed a trace-root write failure")
+	}
+}
+
+func TestSynchronizedFilesystemRecorderSupportsConcurrentWrites(t *testing.T) {
+	root := t.TempDir()
+	recorder, err := NewFilesystemRecorder(root)
+	if err != nil {
+		t.Fatal(err)
+	}
+	recorder = pipeline.SynchronizedDebugRecorder(recorder)
+
+	const writes = 16
+	var wg sync.WaitGroup
+	errs := make(chan error, writes)
+	for i := 0; i < writes; i++ {
+		i := i
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			errs <- recorder.WriteBytes(fmt.Sprintf("attempt/%02d/data", i), []byte("payload"))
+		}()
+	}
+	wg.Wait()
+	close(errs)
+	for err := range errs {
+		if err != nil {
+			t.Fatal(err)
+		}
+	}
+	for i := 0; i < writes; i++ {
+		if _, err := os.Stat(filepath.Join(root, "attempt", fmt.Sprintf("%02d", i), "data")); err != nil {
+			t.Fatalf("trace artifact %d: %v", i, err)
+		}
+	}
+}