From atum-stack-backend
Provides guidance for property-based testing across multiple languages and smart contracts. Use when writing tests, reviewing code with serialization/validation/parsing patterns, designing features, or when property-based testing would provide stronger coverage than example-based tests.
npx claudepluginhub arnwaldn/atum-plugins-collection --plugin atum-stack-backendThis skill uses the workspace's default tool permissions.
Use this skill proactively during development when you encounter patterns where PBT provides stronger coverage than example-based tests.
Searches, retrieves, and installs Agent Skills from prompts.chat registry using MCP tools like search_skills and get_skill. Activates for finding skills, browsing catalogs, or extending Claude.
Searches prompts.chat for AI prompt templates by keyword or category, retrieves by ID with variable handling, and improves prompts via AI. Use for discovering or enhancing prompts.
Guides implementation of event-driven hooks in Claude Code plugins using prompt-based validation and bash commands for PreToolUse, Stop, and session events.
Use this skill proactively during development when you encounter patterns where PBT provides stronger coverage than example-based tests.
Invoke this skill when you detect:
encode/decode, serialize/deserialize, toJSON/fromJSON, pack/unpacknormalize, sanitize, clean, canonicalize, formatis_valid, validate, check_* (especially with normalizers)add/remove/get operationsPriority by pattern:
| Pattern | Property | Priority |
|---|---|---|
| encode/decode pair | Roundtrip | HIGH |
| Pure function | Multiple | HIGH |
| Validator | Valid after normalize | MEDIUM |
| Sorting/ordering | Idempotence + ordering | MEDIUM |
| Normalization | Idempotence | MEDIUM |
| Builder/factory | Output invariants | LOW |
| Smart contract | State invariants | HIGH |
Do NOT use this skill for:
| Property | Formula | When to Use |
|---|---|---|
| Roundtrip | decode(encode(x)) == x | Serialization, conversion pairs |
| Idempotence | f(f(x)) == f(x) | Normalization, formatting, sorting |
| Invariant | Property holds before/after | Any transformation |
| Commutativity | f(a, b) == f(b, a) | Binary/set operations |
| Associativity | f(f(a,b), c) == f(a, f(b,c)) | Combining operations |
| Identity | f(x, identity) == x | Operations with neutral element |
| Inverse | f(g(x)) == x | encrypt/decrypt, compress/decompress |
| Oracle | new_impl(x) == reference(x) | Optimization, refactoring |
| Easy to Verify | is_sorted(sort(x)) | Complex algorithms |
| No Exception | No crash on valid input | Baseline property |
Strength hierarchy (weakest to strongest): No Exception → Type Preservation → Invariant → Idempotence → Roundtrip
Based on the current task, read the appropriate section:
TASK: Writing new tests
→ Read [{baseDir}/references/generating.md]({baseDir}/references/generating.md) (test generation patterns and examples)
→ Then [{baseDir}/references/strategies.md]({baseDir}/references/strategies.md) if input generation is complex
TASK: Designing a new feature
→ Read [{baseDir}/references/design.md]({baseDir}/references/design.md) (Property-Driven Development approach)
TASK: Code is difficult to test (mixed I/O, missing inverses)
→ Read [{baseDir}/references/refactoring.md]({baseDir}/references/refactoring.md) (refactoring patterns for testability)
TASK: Reviewing existing PBT tests
→ Read [{baseDir}/references/reviewing.md]({baseDir}/references/reviewing.md) (quality checklist and anti-patterns)
TASK: Test failed, need to interpret
→ Read [{baseDir}/references/interpreting-failures.md]({baseDir}/references/interpreting-failures.md) (failure analysis and bug classification)
TASK: Need library reference
→ Read [{baseDir}/references/libraries.md]({baseDir}/references/libraries.md) (PBT libraries by language, includes smart contract tools)
When you detect a high-value pattern while writing tests, offer PBT as an option:
"I notice
encode_message/decode_messageis a serialization pair. Property-based testing with a roundtrip property would provide stronger coverage than example tests. Want me to use that approach?"
If codebase already uses a PBT library (Hypothesis, fast-check, proptest, Echidna), be more direct:
"This codebase uses Hypothesis. I'll write property-based tests for this serialization pair using a roundtrip property."
If user declines, write good example-based tests without further prompting.
Do not accept these shortcuts: