Added New Tests in Signum

[imSanko]

Describe your change:

Added new tests in Signum

• Add an algorithm?
• Fix a bug or typo in an existing algorithm?
• Add or change doctests? -- Note: Please avoid changing both code and tests in a single pull request.
• Documentation change?

Checklist:

• I have read CONTRIBUTING.md.
• This pull request is all my own work -- I have not plagiarized.
• I know that pull requests will not be merged if they fail the automated tests.
• This PR only changes one algorithm file. To ease review, please open separate PRs for separate algorithms.
• All new Python files are placed inside an existing directory.
• All filenames are in all lowercase characters with no spaces or dashes.
• All functions and variable names follow Python naming conventions.
• All function parameters and return values are annotated with Python type hints.
• All functions have doctests that pass the automated testing.
• All new algorithms include at least one URL that points to Wikipedia or another similar explanation.
• If this pull request resolves one or more open issues then the description above includes the issue number(s) with a closing keyword.

[cclauss]

Please do NOT remove tests. The original developer might have had very good reasons for creating those particular tests.

Also, please run python3 -m doctest -v maths/signum.py on your own computer so you know if your proposed changes are going to pass the build test

=================================== FAILURES ===================================
________________________ [doctest] maths.signum.signum _________________________
007 
008      Applies signum function on the number
009 
010     Custom test cases:
011     >>> signum(-20)
Expected:
    -2
Got:
    -1

Finally, please try to add tests that show how the algorithm fails with difficult or garbage input.

     >>> signum(-21)
     >>> signum(1_000_000_000)
     >>> signum(12.345)
     >>> signum("a")
     >>> signum([])

[cclauss]

Please bring back the old tests and add more.

[imSanko]

Please bring back the old tests and add more.

Does it meet the requirements or can you tell me I'll add more tests?

[cclauss]

a few more

[cclauss]

 021     >>> signum([])
UNEXPECTED EXCEPTION: TypeError("'<' not supported between instances of 'list' and 'int'")
Traceback (most recent call last):
  File "/opt/hostedtoolcache/Python/3.12.0/x64/lib/python3.12/doctest.py", line 1357, in __run
    exec(compile(example.source, filename, "single",
  File "<doctest maths.signum.signum[4]>", line 1, in <module>
  File "/home/runner/work/Python/Python/maths/signum.py", line 28, in signum
    if num < 0:
       ^^^^^^^
TypeError: '<' not supported between instances of 'list' and 'int'
/home/runner/work/Python/Python/maths/signum.py:21: UnexpectedException

[imSanko]

 021     >>> signum([])
UNEXPECTED EXCEPTION: TypeError("'<' not supported between instances of 'list' and 'int'")
Traceback (most recent call last):
  File "/opt/hostedtoolcache/Python/3.12.0/x64/lib/python3.12/doctest.py", line 1357, in __run
    exec(compile(example.source, filename, "single",
  File "<doctest maths.signum.signum[4]>", line 1, in <module>
  File "/home/runner/work/Python/Python/maths/signum.py", line 28, in signum
    if num < 0:
       ^^^^^^^
TypeError: '<' not supported between instances of 'list' and 'int'
/home/runner/work/Python/Python/maths/signum.py:21: UnexpectedException

Test cases have passed
7 tests in signum.signum
7 tests in 3 items.
7 passed and 0 failed.
Test passed.

[imSanko]

@cclauss Thanks a lot for mentoring me

[cclauss]

The trick is NOT to change the code to fix the test but to change ONLY the test to describe how the code ACTUALLY works.