add failing tests
`as_sql` never accepts a single argument: 1; such mode only existed until commit aeb0f6f which is before the first release.
Merge pull request #40 from kazuho/kazuho/issues/38

Fix issue 38: update() and delete() cannot use SQL::QueryMaker
Checking in changes prior to tagging of version 1.19.

Changelog diff is:

diff --git Changes Changes
index 62338c6..edca602 100644
--- Changes
+++ Changes
@@ -2,6 +2,11 @@ Revision history for Perl module SQL::Maker

 {{$NEXT}}

+1.19 2014-07-30T09:32:20Z
+
+    - Fix issue 38: update() and delete() cannot use SQL::QueryMaker
+      (Kazuho Oku)
+
 1.18 2014-07-25T23:52:14Z

     Handle `limit 0` correctly.
DateTime is a optional testing deps. CLose #39
Checking in changes prior to tagging of version 1.20.

Changelog diff is:

diff --git Changes Changes
index edca602..ca455e2 100644
--- Changes
+++ Changes
@@ -2,6 +2,11 @@ Revision history for Perl module SQL::Maker

 {{$NEXT}}

+1.20 2014-07-31T20:59:30Z
+
+    - DateTime is a testing deps
+      (Gelu Lupas)
+
 1.19 2014-07-30T09:32:20Z

     - Fix issue 38: update() and delete() cannot use SQL::QueryMaker
Revert "Get rid of DateTime dependency"

This reverts commit 0ef4d4d31512d801978f161005c8db6f7b8ca49c.
Merge remote-tracking branch 'upstream/master'