metamorphic-test-generator

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.

Install with Tessl CLI

npx tessl i github:ArabelaTso/Skills-4-SE --skill metamorphic-test-generator

What are skills?

Review — 75%

Does it follow best practices?

If you maintain this skill, you can automatically optimize it using the tessl CLI to improve its score:

npx tessl skill review --optimize ./path/to/skill

Learn more

Validation — 11 / 11 Passed

Validation for skill structure

SKILL.md

Review

Evals

Evaluation results

100%

52%

Expanding Test Coverage for Department Reporting Aggregator

Correct script invocation and CLI usage

Criteria

Without context

With context

generate.py used

100%

Program as first arg

100%

--tests flag used

100%

--properties flag used

100%

--output flag used

100%

report.json exists

100%

report original_tests field

100%

report generated_tests field

100%

report violations field

100%

Test case input field

100%

Without context: $0.3956 · 2m 32s · 20 turns · 25 in / 7,130 out tokens

With context: $0.5486 · 1m 46s · 25 turns · 27 in / 4,835 out tokens

65%

-11%

Validating Tier Pricing Multiplier with Metamorphic Testing

Properties JSON file with parameterized multiplication and suite output

Criteria

Without context

With context

properties.json exists

100%

Top-level properties key

100%

Object form used

100%

name key present

100%

factor key present

53%

33%

Expanded suite file exists

100%

Suite original_tests key

100%

Suite generated_tests key

100%

Report exists

100%

Multiplication in report

75%

100%

Without context: $1.0347 · 4m 6s · 47 turns · 52 in / 10,452 out tokens

With context: $0.5885 · 2m 56s · 24 turns · 7,156 in / 5,621 out tokens

100%

55%

Metamorphic Testing for an Identifier Deduplication Service

Custom MetamorphicProperty class extension

Criteria

Without context

With context

MetamorphicProperty referenced

100%

Subclass defined

100%

__init__ with super() call

100%

transform_input defined

100%

verify_output defined

100%

verify_output returns bool

100%

verify_output returns message

100%

Property registered

70%

100%

report.json exists

100%

Non-trivial transform

100%

Without context: $0.5627 · 3m 46s · 24 turns · 28 in / 8,627 out tokens

With context: $0.8650 · 4m 18s · 28 turns · 31 in / 11,941 out tokens

Evaluated: about 20 hours ago
Agent: Claude Code

Table of Contents

Expanding Test Coverage for Department Reporting Aggregator Validating Tier Pricing Multiplier with Metamorphic Testing Metamorphic Testing for an Identifier Deduplication Service

Is this your skill?

If you maintain this skill, you can claim it as your own. Once claimed, you can manage eval scenarios, bundle related skills, attach documentation or rules, and ensure cross-agent compatibility.