we need more testcases (yet again)
missing test for function std::unique_ptr<xerus::Tensor> xerus::TensorNetwork::fully_contracted_tensor() const (src/xerus/tensorNetwork.cpp:99)
missing test for function xerus::Polynomial& xerus::Polynomial::orthogonolize(const std::vector<xerus::Polynomial>&, const std::function<double(double)>&, double, double) (src/xerus/misc/simpleNumerics.cpp:182)
missing test for function xerus::TensorNetwork& xerus::TensorNetwork::operator=(xerus::TensorNetwork&&) (src/xerus/tensorNetwork.cpp:165)
also:
- specialized_sum is never called with TTOperators
- index operator / is not tested