OAK-2363: NPE in DocumentNodeStore#retrieve for non existing checkpoint
Add null check and test case

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1646236 13f79535-47bb-0310-9956-ffa450edef68
OAK-2365: Refactor node store tests
Also run the tests against the memory node store

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1646264 13f79535-47bb-0310-9956-ffa450edef68
OAK-2365: Refactor node store tests
Move the relevant tests to spi/state and drop Kernel from the name

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1646265 13f79535-47bb-0310-9956-ffa450edef68
OAK-2365: Refactor node store tests
Refactor tests to use common functionality provided by OakBaseTest

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1646266 13f79535-47bb-0310-9956-ffa450edef68
OAK-2365: Refactor node store tests
Correct setup and teardown of node store

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1646273 13f79535-47bb-0310-9956-ffa450edef68
OAK-2056: Optimize orderings by date fields

- Compared literals when possible in case of dates
- covered the compareTo with unit test for dates

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1646274 13f79535-47bb-0310-9956-ffa450edef68
OAK-2365: Refactor node store tests
Simplify MongoMK fixture

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1646278 13f79535-47bb-0310-9956-ffa450edef68