Spike use of a mutation testing framework.

[sageserpent-open]

Evaluate Stryker4s and ScalaMu.

[sageserpent-open]

The motivation behind this is driven by the need to keep adjusting the extent to which Scalacheck hammers the various test suites, especially the world specifications. When these test were written, a lot of manual fault injection was performed to verify that they really did test effctively. However, I have become concerned that the recent repeated turning down of the dials to placate Travis may have made these tests ineffective at detecting faults, so mutation testing would be a nice blanket approach to checking this.

[sageserpent-open]

Did some experimenting with Stryker4s on 'BlobStorageImplementation' and found it quite effective. Some patching of the sources was required (eta-expansions) to get it building with Stryker4s; nevertheless that tool is worth investigating further.