Add interpolation search tests

[jonatan5524]

Description of new feature, or changes

Fix bug in interpolation search where the division is not floored, this is what prevented the 100% coverage and also there are cases where the number were not found (covered in the new test)

adding a test to cover 100% coverage

Checklist

• [x] Your branch is up-to-date with the base branch
• [x] You've included at least one test if this is a new feature
• [x] All tests are passing

Related Issues and Discussions

making progress in #30

People to notify

@manrajgrover