Add CSR view tests

[KyleVaughn]

Description:

Write tests that ensure that the code written for #37 functions properly

Tasks:

• [ ] Implement tests to ensure that the following types of matrices are properly printed/written to a file
  • [ ] Trivial pre-specified/hard-coded matrix
  • [ ] Very, very large matrix that might cause formatting problems
  • [ ] Zero-element matrix
  • [ ] Single-element matrix
  • [ ] Matrix with a row containing only zeros
  • [ ] Empty matrix of valid size
  • [ ] Symmetric matrix
• [ ] Implement tests that check for the following behaviors
  • [ ] The methods work the same for both float and double types
  • [ ] The methods do not change the matrix's data
  • [ ] The methods for writing to a file check for invalid filepaths

Definition of done:

• [ ] All the above tasks are done
• [ ] Written tests follow the testing framework specified in tests/unit_test_framework.hpp
• [ ] Written tests also follows other conventions used by rest of the of the library
• [ ] Code executing these tests compiles successfully
• [ ] Tests are compatible with the specifications of #37
• [ ] Code is commented and documented in a manner that allows anyone familiar with sparse matrices to understand how it works.

[NiloyGupta-UM]

@xianyu2023umich Ready for review

[bjorngkierulf]

@xianyu2023umich I believe I'm reviewing this. Looks good.