Travis not able to run slow canvas test?

[mccalluc]

On Travis, PRs #148 and #149 consistently fail, but only on Travis. Something about the test which includes the creation of the large matrix causes a failure in the next test. Constructing the matrix is slow, even locally, so there might be a race condition. Or maybe something about demo_5.js changes the global environment? I don't know.

[mccalluc]

Using a much smaller matrix fixed this.