Code coverage dropped by 1%

[ncrubin]

In PR #128 where I fixed the Taylor expansion limit and max_expansion limit logic I introduced a logic path but did not explicitly test this path. Code coverage for the wavefunction.py module thus dropped 1%

Name                                                   Stmts   Miss  Cover   Missing
------------------------------------------------------------------------------------
src/fqe/__init__.py                                        3      0   100%
src/fqe/_fqe_control.py                                  146      0   100%
src/fqe/_version.py                                        2      0   100%
src/fqe/bitstring.py                                      55      0   100%
src/fqe/cirq_utils.py                                     40      0   100%
src/fqe/fci_graph.py                                     230      0   100%
src/fqe/fci_graph_set.py                                 105      0   100%
src/fqe/fqe_data.py                                     1472      0   100%
src/fqe/fqe_data_set.py                                  482      0   100%
src/fqe/fqe_decorators.py                                190      0   100%
src/fqe/fqe_ops/__init__.py                                1      0   100%
src/fqe/fqe_ops/fqe_operator.py                           13      0   100%
src/fqe/fqe_ops/fqe_ops.py                                60      0   100%
src/fqe/fqe_ops/fqe_ops_utils.py                          50      0   100%
src/fqe/hamiltonians/__init__.py                           1      0   100%
src/fqe/hamiltonians/diagonal_coulomb.py                  38      0   100%
src/fqe/hamiltonians/diagonal_hamiltonian.py              30      0   100%
src/fqe/hamiltonians/general_hamiltonian.py               48      0   100%
src/fqe/hamiltonians/gso_hamiltonian.py                   48      0   100%
src/fqe/hamiltonians/hamiltonian.py                       34      0   100%
src/fqe/hamiltonians/hamiltonian_utils.py                 90      0   100%
src/fqe/hamiltonians/restricted_hamiltonian.py            48      0   100%
src/fqe/hamiltonians/sparse_hamiltonian.py                74      0   100%
src/fqe/hamiltonians/sso_hamiltonian.py                   54      0   100%
src/fqe/lib/__init__.py                                   10      1    90%   14
src/fqe/lib/bitstring.py                                  19      0   100%
src/fqe/lib/cirq_utils.py                                 11      0   100%
src/fqe/lib/fci_graph.py                                  63      1    98%   128
src/fqe/lib/linalg.py                                     21      0   100%
src/fqe/lib/wick.py                                       24      0   100%
src/fqe/openfermion_utils.py                             146      0   100%
src/fqe/settings.py                                        9      0   100%
src/fqe/tensor/__init__.py                                 2      0   100%
src/fqe/tensor/tensor_utils.py                            61      0   100%
src/fqe/transform.py                                      42      0   100%
src/fqe/util.py                                          227      0   100%
src/fqe/wavefunction.py                                  623      2    99%   566, 598
src/fqe/wick.py                                          341      0   100%
tests/__init__.py                                          0      0   100%

Lines 566 and 598 are the additional for-else logic I added. A small test that builds a Hamiltonian and then sets max_expansion 1 one (so that Taylor and Chebyshev) won't converge is needed to test the Runtime error that should be raised.