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Assertions

When to use vs throwing an Exception

Only to help other devs

  • documenting your understanding of the code at a point

    • guarantees about
      • inputs (preconditions)
      • program state (invariants)
      • outputs (post-conditions)
      • like CSC494 & contracts
  • debugging a broken algo

if condition1:
    pass
else:
    assert False, (
    "This should never happen, but it does sometimes."
    "We're trying to figure out why. Email us if you hit this!")

When to not use assertions

  • data processing
  • data validation
  • error handling

  • assertions are usually disabled in prod

    • performance
  • don't cause side-effects in assertions

assert treeDepth() == 7;

Last update: 2022-09-23