diff --git a/tests/test_data_posting.py b/tests/test_data_posting.py
index 9bd33473c38792d2d6b7474e2033d779bcae55c1..a53b1811bea9e1449e5e7d94ba701687234dd38d 100644
--- a/tests/test_data_posting.py
+++ b/tests/test_data_posting.py
@@ -82,3 +82,27 @@ def test_from_entries_mix_txns_and_other_directives(simple_txn):
         assert all(source[x] == post[x] for x in range(len(source) - 1))
         assert isinstance(post.account, data.Account)
         assert post.meta['note']  # Only works with PostingMeta
+
+@pytest.mark.parametrize('cost_num', [105, 110, 115])
+def test_at_cost(cost_num):
+    post = data.Posting(
+        'Income:Donations',
+        testutil.Amount(25, 'EUR'),
+        testutil.Cost(cost_num, 'JPY'),
+        None,
+        '*',
+        None,
+    )
+    assert post.at_cost() == testutil.Amount(25 * cost_num, 'JPY')
+
+def test_at_cost_no_cost():
+    amount = testutil.Amount(25, 'EUR')
+    post = data.Posting(
+        'Income:Donations',
+        amount,
+        None,
+        None,
+        '*',
+        None,
+    )
+    assert post.at_cost() == amount