Add tests for nested recarrays
diff --git a/example/example20.py b/example/example20.py
index 0e42c68..83725b5 100644
--- a/example/example20.py
+++ b/example/example20.py
@@ -2,7 +2,7 @@
 from __future__ import print_function
 
 import numpy as np
-from example import create_rec_simple, create_rec_packed
+from example import create_rec_simple, create_rec_packed, create_rec_nested
 
 
 def check_eq(arr, data, dtype):
@@ -14,12 +14,25 @@
 packed_dtype = np.dtype([('x', '?'), ('y', 'u4'), ('z', 'f4')])
 
 for func, dtype in [(create_rec_simple, simple_dtype), (create_rec_packed, packed_dtype)]:
+    arr = func(0)
+    assert arr.dtype == dtype
+    check_eq(arr, [], simple_dtype)
+    check_eq(arr, [], packed_dtype)
+
     arr = func(3)
     assert arr.dtype == dtype
     check_eq(arr, [(False, 0, 0.0), (True, 1, 1.5), (False, 2, 3.0)], simple_dtype)
     check_eq(arr, [(False, 0, 0.0), (True, 1, 1.5), (False, 2, 3.0)], packed_dtype)
 
-    arr = func(0)
-    assert arr.dtype == dtype
-    check_eq(arr, [], simple_dtype)
-    check_eq(arr, [], packed_dtype)
+
+nested_dtype = np.dtype([('a', simple_dtype), ('b', packed_dtype)])
+
+arr = create_rec_nested(0)
+assert arr.dtype == nested_dtype
+check_eq(arr, [], nested_dtype)
+
+arr = create_rec_nested(3)
+assert arr.dtype == nested_dtype
+check_eq(arr, [((False, 0, 0.0), (True, 1, 1.5)),
+               ((True, 1, 1.5), (False, 2, 3.0)),
+               ((False, 2, 3.0), (True, 3, 4.5))], nested_dtype)