storage/mem: implement size enforcer for #88

pkg/storage/mem/store_test.go

@@ -1,7 +1,9 @@
 package mem
 
 import (
+	"sync"
 	"testing"
+	"time"
 
 	"github.com/jhillyerd/inbucket/pkg/config"
 	"github.com/jhillyerd/inbucket/pkg/storage"
@@ -16,3 +18,65 @@ func TestSuite(t *testing.T) {
 		return s, destroy, nil
 	})
 }
+
+// TestMessageList verifies the operation of the global message list: mem.Store.messages.
+func TestMaxSize(t *testing.T) {
+	maxSize := int64(2048)
+	s, _ := New(config.Storage{Params: map[string]string{"maxkb": "2"}})
+	boxes := []string{"alpha", "beta", "whiskey", "tango", "foxtrot"}
+	n := 10
+	// total := 50
+	sizeChan := make(chan int64, len(boxes))
+	// Populate mailboxes concurrently.
+	for _, mailbox := range boxes {
+		go func(mailbox string) {
+			size := int64(0)
+			for i := 0; i < n; i++ {
+				_, nbytes := test.DeliverToStore(t, s, mailbox, "subject", time.Now())
+				size += nbytes
+			}
+			sizeChan <- size
+		}(mailbox)
+	}
+	// Wait for sizes.
+	sentBytesTotal := int64(0)
+	for range boxes {
+		sentBytesTotal += <-sizeChan
+	}
+	// Calculate actual size.
+	gotSize := int64(0)
+	s.VisitMailboxes(func(messages []storage.Message) bool {
+		for _, m := range messages {
+			gotSize += m.Size()
+		}
+		return true
+	})
+	// Verify state. Messages are ~75 bytes each.
+	if gotSize < 2048-75 {
+		t.Errorf("Got total size %v, want greater than: %v", gotSize, 2048-75)
+	}
+	if gotSize > maxSize {
+		t.Errorf("Got total size %v, want less than: %v", gotSize, maxSize)
+	}
+	// Purge all messages concurrently, testing for deadlocks.
+	wg := &sync.WaitGroup{}
+	wg.Add(len(boxes))
+	for _, mailbox := range boxes {
+		go func(mailbox string) {
+			err := s.PurgeMessages(mailbox)
+			if err != nil {
+				t.Fatal(err)
+			}
+			wg.Done()
+		}(mailbox)
+	}
+	wg.Wait()
+	count := 0
+	s.VisitMailboxes(func(messages []storage.Message) bool {
+		count += len(messages)
+		return true
+	})
+	if count != 0 {
+		t.Errorf("Got %v total messages, want: %v", count, 0)
+	}
+}