Advanced Features

Prism provides advanced features for comprehensive test validation and analysis.

Snapshot Testing

Capture and compare test results against saved snapshots.

Update Snapshots

Save current test results as the expected baseline:

vendor/bin/prism test --update-snapshots

Check Against Snapshots

Compare current results against saved snapshots:

vendor/bin/prism test --check-snapshots

Snapshot Output

Snapshot Comparison: my-validator

Changes Detected:
  ✓ New passing tests: 12
  ✗ New failing tests: 3
  ~ Changed tests: 7

Detailed Changes:
  + test-123: null → PASS
  - test-456: PASS → FAIL
  ~ test-789: PASS → PASS (duration: 0.12s → 0.34s)

Recommendation: Review changes before updating snapshots

Use Cases

• Regression detection: Identify unexpected behavior changes
• Refactoring safety: Ensure validator behavior unchanged
• CI validation: Verify test results match expectations

Workflow Example

# Establish baseline
vendor/bin/prism test --update-snapshots

# Make changes to validator
vim src/Validator.php

# Verify no regressions
vendor/bin/prism test --check-snapshots

Fuzzing and Test Generation

Generate random test cases to discover edge cases:

vendor/bin/prism test --fuzz 1000

Generates and runs 1000 random test cases per validator.

What Gets Generated

1. Edge Cases

   • null, true, false
   • Integer boundaries (PHP_INT_MAX, PHP_INT_MIN, 0, -1, 1)
   • Float edge cases (0.0, -0.0)
   • String edge cases (empty, whitespace, single char)
   • Large strings (1000, 10000 characters)
   • Array edge cases (empty, nested, mixed types)
   • Object structures

2. Random Data

   • Random integers (-1000 to 1000)
   • Random floats
   • Random strings (0-100 characters)
   • Random arrays (0-10 elements)
   • Random objects (0-5 properties)

Fuzzing Output

Fuzzing Test Results

Total Fuzzed Tests: 1,000
Passed: 967
Failed: 33

Found 33 failure(s) during fuzzing:

1. fuzz-234
   Description: Fuzzed test with array data
   Error: Maximum nesting depth exceeded
   Duration: 0.0234s

2. fuzz-567
   Description: Fuzzed test with string data
   Error: Invalid UTF-8 sequence
   Duration: 0.0123s

Use Cases

• Edge case discovery: Find unexpected failures
• Robustness testing: Verify validator handles random input
• Security testing: Identify potential vulnerabilities

Example Workflow

# Run fuzzing to discover issues
vendor/bin/prism test --fuzz 5000

# Fix discovered issues
vim src/Validator.php

# Re-run fuzzing to verify fixes
vendor/bin/prism test --fuzz 5000

Validator Comparison

Compare results across multiple validator implementations:

vendor/bin/prism test --compare-validators

Configuration

Define multiple validators in prism.php:

<?php

return [
    new OpisJsonSchemaValidator(),
    new JustValidateValidator(),
    new SwaggestValidator(),
];

Comparison Output

Validator Comparison Report

Validators: opis-json-schema, justvalidate, swaggest
Total Tests: 1,247
Discrepancies: 23

Found 23 test(s) with differing results:

1. draft7/strings/pattern-01
   Description: Pattern validation with anchors
   Agreement: 66.7%
   Results:
     opis-json-schema: PASS (expected: valid, got: valid)
     justvalidate: FAIL (expected: valid, got: invalid)
     swaggest: PASS (expected: valid, got: valid)

2. draft7/numbers/multipleOf-02
   Description: Multiple of with floating point
   Agreement: 33.3%
   Results:
     opis-json-schema: FAIL (expected: valid, got: invalid)
     justvalidate: FAIL (expected: valid, got: invalid)
     swaggest: PASS (expected: valid, got: valid)

Use Cases

• Spec compliance: Verify implementations agree
• Edge case identification: Find interpretation differences
• Migration validation: Compare old vs new validators

Coverage Analysis

Analyze test coverage across groups, files, and tags:

vendor/bin/prism test --coverage

Coverage Output

Test Coverage Analysis

Total Tests: 1,247
Passed: 1,198
Failed: 49
Pass Rate: 96.1%
Coverage Score: 87.3/100

Groups Coverage: 45 unique groups
  properties: 234 tests
  items: 187 tests
  required: 156 tests
  type: 143 tests
  anyOf: 98 tests
  ... and 40 more groups

Files Coverage: 78 unique files
  properties.json: 234 tests
  items.json: 187 tests
  required.json: 156 tests
  type.json: 143 tests
  anyOf.json: 98 tests
  ... and 73 more files

Tags Coverage: 12 unique tags
  required: 687 tests
  optional: 312 tests
  edge-case: 156 tests
  regression: 89 tests
  performance: 3 tests
  ... and 7 more tags

Coverage Score Calculation

Weighted formula:

• 60% pass rate
• 20% group diversity (unique test groups)
• 20% file diversity (unique test files)

Use Cases

• Completeness check: Verify comprehensive coverage
• Gap identification: Find untested areas
• Quality metrics: Track test suite health

Interactive Mode

Menu-driven test configuration and execution:

vendor/bin/prism test --interactive

Interactive Menu

Interactive Mode - Configure and run tests

Current Configuration:
  Filter: <none>
  Tag: <none>
  Parallel: 1 worker(s)
  Incremental: disabled
  Watch: disabled

Select action:
  > Run tests with current configuration
    Set name filter (regex)
    Set tag filter
    Configure parallel workers
    Toggle incremental mode
    Toggle watch mode
    Clear all filters
    Exit

Features

• Real-time configuration: Adjust settings before running
• Filter preview: See current filter configuration
• Immediate execution: Run with configured options
• Persistent session: Keep testing until exit

Use Cases

• Exploratory testing: Try different filter combinations
• Learning: Understand filter behavior interactively
• Quick iteration: Adjust and re-run easily

Multiple Output Formats

Generate test results in various formats:

JSON Output

vendor/bin/prism test --format json

JUnit XML Output

vendor/bin/prism test --format xml

See Output Formats for detailed format specifications.

Combining Advanced Features

Comprehensive CI Pipeline

vendor/bin/prism test \
    -j 8 \
    --profile \
    --coverage \
    --check-snapshots \
    --format json > results.json

Development Workflow

vendor/bin/prism test \
    --watch \
    --incremental \
    --interactive \
    --failures

Quality Assurance

vendor/bin/prism test \
    --compare-validators \
    --fuzz 1000 \
    --coverage \
    --profile

Next Steps

• See output formats for result formats
• Learn about custom assertions
• Explore filtering options