Metamorphic Test Generator

What it does

When your agent uses it

• You need to expand test suites
• Test programs without oracles
• Validate mathematical
• Algorithmic properties

Example prompts

• “/metamorphic-test-generator”

Requirements

• Python 3

Workflow steps

5 steps, taken from the first numbered list in SKILL.md.

1. 1Follow-up Test Cases - New inputs derived from original tests
2. 2Property Verification - Checks that outputs satisfy metamorphic relations
3. 3Violation Reports - Identifies property violations and anomalies
4. 4Expanded Test Suite - Original plus generated tests
5. 5Coverage Summary - Property coverage and effectiveness

What it can do on your machine

Read from SKILL.md and the folder at commit 4f38503. It shows what the files ask for, not the result of running them.

• Tool permissions

  Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

  From allowed-tools in the SKILL.md frontmatter.

• Runs code

  Ships 1 file in scripts/ (Python), which the agent can run.

  Shell commands in SKILL.md call:

  • python

  From the folder's file list and the shell code blocks in SKILL.md.

• Network

  No URLs in SKILL.md.

  From URLs in SKILL.md, links to its own repository left out.

• Credentials

  Names no API keys, tokens, secrets or passwords.

  From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Metamorphic Test Generator loads about 798 tokens when it runs, and up to ~1.8k if it reads all its reference files. Until then it costs about 166 tokens; SKILL.md has 198 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it

~166

When it runs · the whole SKILL.md, loaded when a task matches

~798

With references · SKILL.md plus every file in references/, read only if the agent opens them

~1.8k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); the scripts in this folder are not scanned.

SKILL.md

The full file from ArabelaTso/Skills-4-SE at commit 4f38503, republished under its Apache-2.0 licence (© ArabelaTso). 198 words, ~798 tokens.

name

metamorphic-test-generator

description

Generate test cases using metamorphic testing by applying transformations based on metamorphic properties. Use when you need to expand test suites, test programs without oracles, validate mathematical or algorithmic properties, or detect subtle bugs through input-output relationships. The skill takes a program, original test cases, and metamorphic properties as input, generates new test cases by applying transformations, executes tests, verifies outputs satisfy properties, reports violations and anomalies, and outputs an expanded test suite with property coverage summary. Supports multiple programming languages and property types.

# Generate metamorphic tests
python scripts/generate.py program.py --tests tests/ --properties properties.json

# Use specific metamorphic properties
python scripts/generate.py program.py --tests tests/ --properties "permutation,addition"

# Generate report
python scripts/generate.py program.py --tests tests/ --properties props.json --output report.json

{
  "original_tests": 20,
  "generated_tests": 60,
  "properties_applied": ["permutation", "addition", "inverse"],
  "violations": 3,
  "property_coverage": 95.0,
  "anomalies": ["inverse property failed for negative inputs"]
}

python scripts/generate.py <program> --tests <test_dir> --properties <properties> [--output <report.json>]

© ArabelaTso, Apache-2.0. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 6 other files (scripts, references, assets) in skills/metamorphic-test-generator of ArabelaTso/Skills-4-SE.

• SKILL.md
• README.md
• assets/example-program.py
• assets/properties-template.json
• assets/test-cases-template.json
• references/properties.md
• scripts/generate.py

Open the folder on GitHubat commit 4f38503