test and fix parallel append

Author: alimanfoo

zarr/core.py

@@ -811,7 +811,7 @@ def __repr__(self):
 
     def __getstate__(self):
         return self._store, self._path, self._read_only, self._chunk_store, \
-               self._synchronizer
+               self._synchronizer, self._cache_metadata
 
     def __setstate__(self, state):
         self.__init__(*state)

zarr/tests/test_sync.py

@@ -46,6 +46,15 @@ def init_attributes(self, store, read_only=False):
                           read_only=read_only)
 
 
+def _append_data(arg):
+    z, i = arg
+    import numpy as np
+    x = np.empty(1000, dtype='i4')
+    x[:] = i
+    z.append(x)
+    return z.shape
+
+
 class MixinArraySyncTests(object):
 
     def test_parallel_append(self):
@@ -55,16 +64,8 @@ def test_parallel_append(self):
         arr[:] = 0
         pool = self.create_pool(cpu_count())
 
-        def f(i):
-            x = np.empty(1000, dtype='i4')
-            x[:] = i
-            arr.append(x)
-
-        pool.map_async(f, range(1, 40, 1))
-
-        pool.close()
-        pool.join()
-        pool.terminate()
+        results = pool.map_async(_append_data, zip([arr] * 39, range(1, 40, 1)))
+        print(results.get())
 
         eq((40000,), arr.shape)