Investigate sporadic test failure.

[sageserpent-open]

Test "A world (using the world efficient in-memory implementation)" should "reveal all the history of a related item up to the 'when' limit of a scope made from it" is failing sporadically.

The frequency of failure is quite low, and it may be related to the test itself, in which case I would expect to see sporadic test failures for the other world implementations too.

[sageserpent-open]

Test failure logs:

testFailureOne.txt

testFailureTwo.txt

[sageserpent-open]

Test failure two was seen in commit: f0f541f.

[sageserpent-open]

Here's another one:

testFailureThree.txt

[sageserpent-open]

... and another:

testFailureFour.txt

[sageserpent-open]

... and another from commit: 95ea3fd

testFailureFive.txt