Give '_Batches' methods more natural names.

tseaver · tseaver · commit 8190f4c13981 · 2015-01-08T15:20:33.000-05:00
Add explicit test of using the stack.
diff --git a/gcloud/datastore/batch.py b/gcloud/datastore/batch.py
@@ -32,13 +32,13 @@ def __init__(self):
         super(_Batches, self).__init__()
         self._stack = []
 
-    @property
-    def stack(self):
-        """Return a copy of our stack."""
-        return self._stack[:]
+    def __iter__(self):
+        """Iterate the stack in LIFO order.
+        """
+        return iter(reversed(self._stack))
 
-    def _push_batch(self, batch):
-        """Push a batch onto our stack.
+    def push(self, batch):
+        """Push a batch / transaction onto our stack.
 
         Intended for use only in :meth:`gcloud.datastore.batch.Batch.__enter__`
 
@@ -47,8 +47,8 @@ def _push_batch(self, batch):
         """
         self._stack.append(batch)
 
-    def _pop_batch(self):
-        """Pop a batch onto our stack.
+    def pop(self):
+        """Pop a batch / transaction from our stack.
 
         Intended for use only in :meth:`gcloud.datastore.batch.Batch.__enter__`
 
@@ -58,6 +58,17 @@ def _pop_batch(self):
         """
         return self._stack.pop()
 
+    @property
+    def top(self):
+        """Get the top-most batch / transaction
+
+        :rtype: :class:`gcloud.datastore.batch.Batch` or
+                :class:`gcloud.datastore.transaction.Transaction` or None
+        :returns: the top-most item, or None if the stack is empty.
+        """
+        if len(self._stack) > 0:
+            return self._stack[-1]
+
 
 _BATCHES = _Batches()
 
@@ -256,7 +267,7 @@ def rollback(self):
         pass
 
     def __enter__(self):
-        _BATCHES._push_batch(self)
+        _BATCHES.push(self)
         self.begin()
         return self
 
@@ -267,4 +278,4 @@ def __exit__(self, exc_type, exc_val, exc_tb):
             else:
                 self.rollback()
         finally:
-            _BATCHES._pop_batch()
+            _BATCHES.pop()
diff --git a/gcloud/datastore/test_batch.py b/gcloud/datastore/test_batch.py
@@ -15,6 +15,34 @@
 import unittest2
 
 
+class Test_Batches(unittest2.TestCase):
+
+    def _getTargetClass(self):
+        from gcloud.datastore.batch import _Batches
+
+        return _Batches
+
+    def _makeOne(self):
+        return self._getTargetClass()()
+
+    def test_it(self):
+        batch1, batch2 = object(), object()
+        batches = self._makeOne()
+        self.assertEqual(list(batches), [])
+        self.assertTrue(batches.top is None)
+        batches.push(batch1)
+        self.assertTrue(batches.top is batch1)
+        batches.push(batch2)
+        self.assertTrue(batches.top is batch2)
+        popped = batches.pop()
+        self.assertTrue(popped is batch2)
+        self.assertTrue(batches.top is batch1)
+        self.assertEqual(list(batches), [batch1])
+        popped = batches.pop()
+        self.assertTrue(batches.top is None)
+        self.assertEqual(list(batches), [])
+
+
 class TestBatch(unittest2.TestCase):
 
     def _getTargetClass(self):
@@ -177,14 +205,14 @@ def test_as_context_mgr_wo_error(self):
         entity = _Entity(_PROPERTIES)
         key = entity.key = _Key(_DATASET)
 
-        self.assertEqual(_BATCHES.stack, [])
+        self.assertEqual(list(_BATCHES), [])
 
         with self._makeOne(dataset_id=_DATASET,
                            connection=connection) as batch:
-            self.assertEqual(_BATCHES.stack, [batch])
+            self.assertEqual(list(_BATCHES), [batch])
             batch.put(entity)
 
-        self.assertEqual(_BATCHES.stack, [])
+        self.assertEqual(list(_BATCHES), [])
 
         self.assertEqual(
             connection._saved,
@@ -201,20 +229,20 @@ def test_as_context_mgr_nested(self):
         entity2 = _Entity(_PROPERTIES)
         key = entity2.key = _Key(_DATASET)
 
-        self.assertEqual(_BATCHES.stack, [])
+        self.assertEqual(list(_BATCHES), [])
 
         with self._makeOne(dataset_id=_DATASET,
                            connection=connection) as batch1:
-            self.assertEqual(_BATCHES.stack, [batch1])
+            self.assertEqual(list(_BATCHES), [batch1])
             batch1.put(entity1)
             with self._makeOne(dataset_id=_DATASET,
                                connection=connection) as batch2:
-                self.assertEqual(_BATCHES.stack, [batch1, batch2])
+                self.assertEqual(list(_BATCHES), [batch2, batch1])
                 batch2.put(entity2)
 
-            self.assertEqual(_BATCHES.stack, [batch1])
+            self.assertEqual(list(_BATCHES), [batch1])
 
-        self.assertEqual(_BATCHES.stack, [])
+        self.assertEqual(list(_BATCHES), [])
 
         self.assertEqual(
             connection._saved,
@@ -233,18 +261,18 @@ def test_as_context_mgr_w_error(self):
         entity = _Entity(_PROPERTIES)
         key = entity.key = _Key(_DATASET)
 
-        self.assertEqual(_BATCHES.stack, [])
+        self.assertEqual(list(_BATCHES), [])
 
         try:
             with self._makeOne(dataset_id=_DATASET,
                                connection=connection) as batch:
-                self.assertEqual(_BATCHES.stack, [batch])
+                self.assertEqual(list(_BATCHES), [batch])
                 batch.put(entity)
                 raise ValueError("testing")
         except ValueError:
             pass
 
-        self.assertEqual(_BATCHES.stack, [])
+        self.assertEqual(list(_BATCHES), [])
 
         self.assertEqual(
             connection._saved,
