Travis build failing when af.inverse is being used

[Balavarun5]

Commit : 3f71b02

Issue

The Travis build for the PR #59 is failing for the test_advection() test function, This test_advection() function uses af.inverse()

[amanabt]

@Balavarun5
First, give the full address of the test function, dg_maxwell/tests/test_waveEqn.py::test_advection.
Second, PR #59 is for 2D advection solver only, test_advection is a part of 1D advection solver.
So, this function should not be written in this PR. Please create a different PR and work on it there.

[Balavarun5]

This test should be there regardless, It's similar to testing a primary function like 1D A-matrix, volume integral term and the surface term.

[amanabt]

I agree that we may build upon the results of this test for 2D advection solver. But that does not explain why this function should be developed in this PR. Let's not make the mistake again of creating huge PR's with many different additions and merging them at once. This only makes the PR confusing.

[Balavarun5]

A PR #63 for this issue has been created