Improve some PHPUnit assertions

[peter279k]

Description

• Improve PHPunit assertions.

Motivation and context

• Using the assertFalse to let expected be false.

How has this been tested?

N/A

Types of changes

• [ ] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)
• [X] Improvements

PR checklist

• [X] My change requires a change to the documentation.
• [X] I have updated the documentation accordingly.
• [X] I have read the CONTRIBUTING.md document.
• [X] I have added tests to cover my changes.

[codecov[bot]]

Codecov Report

Merging #88 (3a2c9b2) into main (0ca6ba5) will decrease coverage by 0.08%. The diff coverage is n/a.

@@             Coverage Diff              @@
##               main      #88      +/-   ##
============================================
- Coverage     96.42%   96.34%   -0.09%     
  Complexity      161      161              
============================================
  Files            14       14              
  Lines           392      383       -9     
============================================
- Hits            378      369       -9     
  Misses           14       14              

Impacted Files	Coverage Δ
src/AbstractCollection.php	96.80% <0.00%> (-0.28%)	:arrow_down:

[ramsey]

Thank you for contributing! 🎉

I committed this in bf292fb3ac4d26450cbd1118f9fa064c699486c5.