ProgramFacts.Shrink (program_facts v0.2.0)

Deterministic minimization helpers for generated failures.

shrink/2 takes a failing program and a predicate that returns true while a candidate still reproduces the failure. It tries smaller generation options and returns the smallest candidate it can find without losing the failure.

Summary

Types

predicate()

result()

step()

Functions

shrink(program, failure?)

Attempts to minimize a failing generated program.

shrink(program, failure?, opts)

Attempts to minimize a failing generated program.

Types

predicate()

@type predicate() :: (ProgramFacts.Program.t() -> boolean())

result()

@type result() :: %{
  program: ProgramFacts.Program.t(),
  options: keyword(),
  steps: [step()]
}

step()

@type step() :: %{from: map(), to: map(), accepted?: boolean(), kind: atom()}

Functions

shrink(program, failure?)

@spec shrink(ProgramFacts.Program.t(), predicate()) :: result()

Attempts to minimize a failing generated program.

failure? must return true for the original program and for each accepted candidate. The result contains the minimized program, its generation options, and a trace of attempted shrink steps.

shrink(program, failure?, opts)

@spec shrink(ProgramFacts.Program.t(), predicate(), keyword()) :: result()

Attempts to minimize a failing generated program.

failure? must return true for the original program and for each accepted candidate. The result contains the minimized program, its generation options, and a trace of attempted shrink steps.