diff --git a/clj-browserchannel/test/net/thegeez/browserchannel/server/array_buffer_tests.clj b/clj-browserchannel/test/net/thegeez/browserchannel/server/array_buffer_tests.clj
index df98318..e5ffd0e 100644
--- a/clj-browserchannel/test/net/thegeez/browserchannel/server/array_buffer_tests.clj
+++ b/clj-browserchannel/test/net/thegeez/browserchannel/server/array_buffer_tests.clj
@@ -6,13 +6,43 @@
   (:import (net.thegeez.browserchannel.server ArrayBuffer)))
 
 (deftest basics-test
-  (let [empty-array (ArrayBuffer. 0 0 (->queue) (->queue))]
-    (is (= (to-flush empty-array)
+  (let [ab (ArrayBuffer. 0 0 (->queue) (->queue))]
+    (is (= (to-flush ab)
        nil))
-    (is (= (last-acknowledged-id empty-array)
+    (is (= (last-acknowledged-id ab)
        0))
-    (is (= (outstanding-bytes empty-array)
-       0))))
+    (is (= (outstanding-bytes ab)
+       0)))
+
+  (let [ab (ArrayBuffer. 3
+                         0
+                         (->queue)
+                         (->queue
+                           [1 "one"]
+                           [2 "two"]
+                           [3 "three"]))]
+    (is (= (first (to-flush ab))
+           [[1 "one"]
+            [2 "two"]
+            [3 "three"]]))
+    (is (= (last-acknowledged-id ab)
+           0))
+    (is (= (outstanding-bytes ab)
+           11)))
+
+  (let [ab (ArrayBuffer. 3
+                         0
+                         (->queue
+                           [1 "one"]
+                           [2 "two"]
+                           [3 "three"])
+                         (->queue))]
+    (is (= (first (to-flush ab))
+           nil))
+    (is (= (last-acknowledged-id ab)
+           0))
+    (is (= (outstanding-bytes ab)
+           0))))
 
 (deftest queue-tests
   (let [ab (-> (ArrayBuffer. 0 0 (->queue) (->queue))
@@ -24,6 +54,16 @@
     (is (= (outstanding-bytes ab)
            3)))
 
+  (let [ab (-> (ArrayBuffer. 1 0 (->queue) (->queue [1 "one"]))
+               (queue "two"))]
+    (is (= (first (to-flush ab))
+           [[1 "one"]
+            [2 "two"]]))
+    (is (= (last-acknowledged-id ab)
+           0))
+    (is (= (outstanding-bytes ab)
+           6)))
+
   (let [ab (-> (ArrayBuffer. 0 0 (->queue) (->queue))
                (queue nil))]
     (is (= (first (to-flush ab))
@@ -58,7 +98,7 @@
     (is (= (first (to-flush flushed))
            nil))))
 
-(deftest acknowledge-tests
+(deftest acknowledge-no-existing-data-tests
   (let [ab (-> (ArrayBuffer. 0 0 (->queue) (->queue))
                (queue "one")
                (queue "two")
@@ -103,3 +143,95 @@
              6))
       (is (= (outstanding-bytes ack-ab)
              0)))))
+
+(deftest acknowledge-existing-ack-data-tests
+  (let [ab (-> (ArrayBuffer. 2
+                             0
+                             (->queue
+                               [1 "one"]
+                               [2 "two"])
+                             (->queue))
+               (queue "three")
+               (queue "four")
+               (queue "five"))]
+    (is (= (first (to-flush ab))
+           [[3 "three"]
+            [4 "four"]
+            [5 "five"]]))
+    (is (= (last-acknowledged-id ab)
+           0))
+
+    (let [ack-ab (acknowledge-id ab 4)]
+      (is (= (first (to-flush ack-ab))
+             [[5 "five"]]))
+      (is (= (last-acknowledged-id ack-ab)
+             4))
+      (is (= (outstanding-bytes ack-ab)
+             4)))
+
+    (let [ack-ab (acknowledge-id ab 2)]
+      (is (= (first (to-flush ack-ab))
+             [[3 "three"]
+              [4 "four"]
+              [5 "five"]]))
+      (is (= (last-acknowledged-id ack-ab)
+             2))
+      (is (= (outstanding-bytes ack-ab)
+             13)))
+
+    (let [ack-ab (acknowledge-id ab 6)]
+      (is (= (first (to-flush ack-ab))
+             nil))
+      (is (= (last-acknowledged-id ack-ab)
+             6))
+      (is (= (outstanding-bytes ack-ab)
+             0)))))
+
+(deftest acknowledge-existing-to-flush-data-tests
+  (let [ab (-> (ArrayBuffer. 2
+                             0
+                             (->queue)
+                             (->queue
+                               [1 "one"]
+                               [2 "two"]))
+               (queue "three")
+               (queue "four")
+               (queue "five"))]
+    (is (= (first (to-flush ab))
+           [[1 "one"]
+            [2 "two"]
+            [3 "three"]
+            [4 "four"]
+            [5 "five"]]))
+    (is (= (last-acknowledged-id ab)
+           0))
+
+    (let [ack-ab (acknowledge-id ab 2)]
+      (is (= (first (to-flush ack-ab))
+             [[3 "three"]
+              [4 "four"]
+              [5 "five"]]))
+      (is (= (last-acknowledged-id ack-ab)
+             2))
+      (is (= (outstanding-bytes ack-ab)
+             13)))
+
+    (let [ack-ab (acknowledge-id ab 0)]
+      (is (= (first (to-flush ack-ab))
+             [[1 "one"]
+              [2 "two"]
+              [3 "three"]
+              [4 "four"]
+              [5 "five"]]))
+      (is (= (last-acknowledged-id ack-ab)
+             0))
+      (is (= (outstanding-bytes ack-ab)
+             19)))
+
+    (let [ack-ab (acknowledge-id ab 6)]
+      (is (= (first (to-flush ack-ab))
+             nil))
+      (is (= (last-acknowledged-id ack-ab)
+             6))
+      (is (= (outstanding-bytes ack-ab)
+             0)))))