Semester Review Topics List

We have learned about randomness, writing consistent signatures for big-bang, writing high quality tests, and how to limit numerical values.

Recent major topics

• Randomness

  • Work with a non-random function first.
    • Non-random function has more parameters than random version.
    • Testable.
  • Random function
    • Calls non-random function with random input.
    • Not usually tested.

• Signatures / Big-Bang

  • Information flow must be consistent
  • Write signatures for everything
  • Test everything individually
  • Use check-with to catch signature errors. (See below.)

• Testing

  • Write two tests for each function.
  • Especially when you do not know how to make it work! (Fight instinct to just hack.)
  • Use different numbers for each argument in a test. (Why is this important?)

Minor Topics

Still important enough to mention.

• Numerical functions that limit or convert values:

  • min, max to limit values
  • real->int
  • round, ceiling, floor

• People coordinates

  • Changing to and from

• String functions.

  • substring: both the two and three argument versions.

Details on check-with

Example in big-bang is: (check-with posn?). More in click-circle writeup. The check-with command is first introduced in Chapter 8, book page 137, PDF page 148.