Test cases for depts

[akarki2005]

Proposed Changes

• Added unit tests for the depts function in the backend (tested with empty db, one course and multiple courses (one test w/ same departments and one w/ unique departments))
• Updated project documentation to include instructions for running backend tests using the stack program

Type of Change

(Write an X or a brief description next to the type or types that best describe your changes.)

Type	Applies?
🚨 Breaking change (fix or feature that would cause existing functionality to change)
✨ New feature (non-breaking change that adds functionality)
🐛 Bug fix (non-breaking change that fixes an issue)
🎨 User interface change (change to user interface; provide screenshots)
♻️ Refactoring (internal change to codebase, without changing functionality)
🚦 Test update (change that only adds or modifies tests)	X
📦 Dependency update (change that updates a dependency)
🔧 Internal (change that only affects developers or continuous integration)

Checklist

(Complete each of the following items for your pull request. Indicate that you have completed an item by changing the [ ] into a [x] in the raw text, or by clicking on the checkbox in the rendered description on GitHub.)

Before opening your pull request:

• I have performed a self-review of my changes.
  • Check that all changed files included in this pull request are intentional changes.
  • Check that all changes are relevant to the purpose of this pull request, as described above.
• [N/A] I have added tests for my changes, if applicable.
  • This is required for all bug fixes and new features.
• [N/A] I have updated the project documentation, if applicable.
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[coveralls]

Pull Request Test Coverage Report for Build cc642415-8632-4d63-90e3-b61e5c116913

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.4%) to 40.785%

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Totals
Change from base Build d13f5875-3c03-4978-8cb3-ac694f66efb1:	0.4%
Covered Lines:	634
Relevant Lines:	1520

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💛 - Coveralls

[akarki2005]

Hi @david-yz-liu, I have made the requested changes to the PR. On a related note, I was wondering if refactoring the backend test structure (in the .cabal file) so that related tests can be run in isolation (with $ stack test :<test-suite-name>) is something that could be explored. Currently, all tests are in a single test suite Tests, and I think increasing modularity of the test suites (so that something like $ stack test :Controllers / $ stack test :RequirementTests / $ stack test :SvgTests works) would help to improve the developer experience for testing.