test(http): cover scope-safe removal on TUS upload eviction

Refs GHSA-m9f5-2232-frp6

http/upload_cache_memory_test.go

@@ -0,0 +1,42 @@
+package fbhttp
+
+import (
+	"os"
+	"path/filepath"
+	"sync"
+	"testing"
+	"time"
+)
+
+// On expiry the memory upload cache must delete an abandoned upload through the
+// registered scoped removal callback, not with a raw os.Remove on the cached
+// path. This test registers an entry keyed by a real file's path whose callback
+// does not delete the file; if the old raw os.Remove behaviour were still in
+// place the file (whose path is the key) would be removed.
+func TestMemoryUploadCacheEvictionUsesRemovalCallback(t *testing.T) {
+	c := newMemoryUploadCache()
+	t.Cleanup(c.Close)
+
+	f := filepath.Join(t.TempDir(), "partial.upload")
+	if err := os.WriteFile(f, []byte("x"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	done := make(chan struct{})
+	var once sync.Once
+	// Deliberately do NOT delete the file here.
+	c.cache.Set(f, memoryUploadEntry{size: 1, remove: func() error {
+		once.Do(func() { close(done) })
+		return nil
+	}}, time.Millisecond)
+
+	select {
+	case <-done:
+	case <-time.After(2 * time.Second):
+		t.Fatal("eviction did not invoke the removal callback")
+	}
+
+	if _, err := os.Stat(f); err != nil {
+		t.Fatalf("file at the cache key was deleted, so eviction bypassed the callback (raw os.Remove?): %v", err)
+	}
+}