tiny.hypothesis

Overview · API · Code relationships · Verification · Audit

Overview

Runs tests by searching for inputs that make a test fail. A function that draws its inputs and fails when the claim under test fails for them is a property. Every draw goes through the run's data object, which appends the choice with its kind, its value, and the bounds it was drawn within. The recorded list of the draws a property made is the choice sequence. Because the draws are recorded in order, a later run can feed the same sequence back into the same generator and get the same input.

The search for a smaller choice sequence that still fails is shrinking. A generator can label a range of the choice sequence, opened and closed around a part of the generator, as a span, which gives shrinking a unit to delete or simplify. Shrinking replays a candidate sequence through the property and keeps the candidate when the property still fails, within the run's shrink budget. The passes delete spans, replace a span with its simplest value, and reduce individual choices.

A property can report a finite number to say how interesting its input was as a target score, and the engine then spends a further budget mutating the best-scoring sequence to raise that score.

A failing sequence is saved to the directory called the failure database and replayed first on the next run. Limits for one run, called settings, bound a run by examples, replays, choices, input bytes, shrinks, and targeted attempts, with quick, dev, and ci presets scaling all of them together.

Definitions

Actions

Public operations.

• Strategy
• BoundedArray
• fuzzWithSettings
• target
• check
• checkNamed
• forAll
• forAllNamed
• fuzz
• checkFn
• auto
• Generator
• fixedArray
• float32
• checkValue
• checkValueAlloc
• list
• tuple
• bytes
• float64
• integer
• oneOf
• boolean
• gen_point
• gen_quaternion
• gen_unit_vec3

Types and contracts

Public types and contracts.

• ConjectureData
• Settings
• CoverageCounts
• ChoiceKind
• ChoiceNode
• Config
• DrawError
• Span
• Status
• TargetError
• TargetObservation
• FuzzInputOptions
• ReplayCursor
• Coverage
• TestResult

Namespaces

Public namespaces.

• conjecture
• coverage
• artifact
• database
• strategies
• swarm
• shrinker
• engine
• autoderive
• value
• composites
• report
• stateful

Code relationships

Direct static dependencies extracted from parsed source by semantic graph analysis.

Uses: tiny.bench, tiny.bumpalo, tiny.smg
Used by: tiny.accy, tiny.arrange, tiny.bench, tiny.bumpalo, tiny.chant, tiny.choir, tiny.closure, tiny.coz, tiny.css, tiny.deadalloc, tiny.deflate, tiny.filigree, tiny.geometry, tiny.gif, tiny.gpalloc, tiny.gui, tiny.http, tiny.linear, tiny.machine, tiny.markdown, tiny.memtrace, tiny.mprompt, tiny.pdf, tiny.peer, tiny.pluck, tiny.png, tiny.preserves, tiny.python, tiny.quic, tiny.reducer, tiny.reticulum, tiny.rig, tiny.sandbox, tiny.sdfii, tiny.simd, tiny.smt, tiny.sql, tiny.stabilizer, tiny.stun, tiny.syn, tiny.sys, tiny.tldr, tiny.trace, tiny.ui, tiny.wayland, tiny.windowing, tiny.xkb

Verification

No verification records are cataloged for this module in this build.

Audit