Design by contract (DbC)

Posted on 09 May, 2024

• First introduced native support was in Eiffel programming language.

• Think of DbC as having if checks before and after you manipulate data inside live code. Yes they are basically assertions.

• Major components of DbC:

  • Precondition

    • Conditions that must be met before a function is executed.

    • Client obligations, supplier benefits.

  • Postcondition

    • Conditions that must be met after a function is executed.

    • Client benefits, supplier obligations.

  • Invariants

    • General rules that must be true for the entire duration of the function.

    • Conditions that must be met before and after a function is executed.

Resources

• How are TDD and DbC related?

  • TDD is external to business logic, DbC is internal.

• Code Contracts in .NET

• Design by Contract and Assertions