tests

A set of system tests for the overall Casserole database.

test_driver.py is a Python test driver that:

Spawns an arbitrary number of nodes on different ports
Performs tests through sending HTTP requests and expecting certain responses.

System Tests

`TestWriteThenRead.py`

This is a standard write and read of the database.

Initialise 10 nodes
Push arbitrary data to a single node.
Read the same data from the single node, expecting matching data.

`TestMultiWriteOfDiffData.py`

This tests with multiple writes of different data to the same node. The latest write should win, eventually.

'Different data' is defined as different StudentName values.
Since the writes are sent in 1 second apart, only the latest write should be read.

`TestMultiWriteToDiffNodes.py`

This tests with multiple writes of different data to different nodes. Again, the latest write should win eventually.