perl-testing

사용 방법

설치 명령을 복사하고 자신의 에이전트 환경에 설치하기 전에 소스 패키지를 확인하세요.
필요한 도구, 인증 정보, 지원 환경은 원본 문서에서 확인하세요.
입력과 원하는 산출물을 설명하고 출처와 결과를 대조하세요.

npx skills add https://github.com/affaan-m/ecc --skill perl-testing

시작 전 확인

설치에는 모델 구독, API 한도, 파일 접근 권한이 포함되지 않습니다.
별점 수와 설치 수는 활동 지표이며 독립적인 품질·보안 검증이 아닙니다.

원본 Skill 문서

원본 저장소의 제목, 예시, 코드, 표, 링크, 이미지를 유지해 표시합니다.

Perl Testing Patterns

Comprehensive testing strategies for Perl applications using Test2::V0, Test::More, prove, and TDD methodology.

When to Activate

Writing new Perl code (follow TDD: red, green, refactor)
Designing test suites for Perl modules or applications
Reviewing Perl test coverage
Setting up Perl testing infrastructure
Migrating tests from Test::More to Test2::V0
Debugging failing Perl tests

TDD Workflow

Always follow the RED-GREEN-REFACTOR cycle.

perl

# Step 1: RED — Write a failing test
# t/unit/calculator.t
use v5.36;
use Test2::V0;

use lib 'lib';
use Calculator;

subtest 'addition' => sub {
    my $calc = Calculator->new;
    is($calc->add(2, 3), 5, 'adds two numbers');
    is($calc->add(-1, 1), 0, 'handles negatives');
};

done_testing;

# Step 2: GREEN — Write minimal implementation
# lib/Calculator.pm
package Calculator;
use v5.36;
use Moo;

sub add($self, $a, $b) {
    return $a + $b;
}

1;

# Step 3: REFACTOR — Improve while tests stay green
# Run: prove -lv t/unit/calculator.t

Test::More Fundamentals

The standard Perl testing module — widely used, ships with core.

Basic Assertions

perl

use v5.36;
use Test::More;

# Plan upfront or use done_testing
# plan tests => 5;  # Fixed plan (optional)

# Equality
is($result, 42, 'returns correct value');
isnt($result, 0, 'not zero');

# Boolean
ok($user->is_active, 'user is active');
ok(!$user->is_banned, 'user is not banned');

# Deep comparison
is_deeply(
    $got,
    { name => 'Alice', roles => ['admin'] },
    'returns expected structure'
);

# Pattern matching
like($error, qr/not found/i, 'error mentions not found');
unlike($output, qr/password/, 'output hides password');

# Type check
isa_ok($obj, 'MyApp::User');
can_ok($obj, 'save', 'delete');

done_testing;

SKIP and TODO

perl

use v5.36;
use Test::More;

# Skip tests conditionally
SKIP: {
    skip 'No database configured', 2 unless $ENV{TEST_DB};

    my $db = connect_db();
    ok($db->ping, 'database is reachable');
    is($db->version, '15', 'correct PostgreSQL version');
}

# Mark expected failures
TODO: {
    local $TODO = 'Caching not yet implemented';
    is($cache->get('key'), 'value', 'cache returns value');
}

done_testing;

Test2::V0 Modern Framework

Test2::V0 is the modern replacement for Test::More — richer assertions, better diagnostics, and extensible.

Why Test2?

Superior deep comparison with hash/array builders
Better diagnostic output on failures
Subtests with cleaner scoping
Extensible via Test2::Tools::* plugins
Backward-compatible with Test::More tests

Deep Comparison with Builders

perl

use v5.36;
use Test2::V0;

# Hash builder — check partial structure
is(
    $user->to_hash,
    hash {
        field name  => 'Alice';
        field email => match(qr/\@example\.com$/);
        field age   => validator(sub { $_ >= 18 });
        # Ignore other fields
        etc();
    },
    'user has expected fields'
);

# Array builder
is(
    $result,
    array {
        item 'first';
        item match(qr/^second/);
        item DNE();  # Does Not Exist — verify no extra items
    },
    'result matches expected list'
);

# Bag — order-independent comparison
is(
    $tags,
    bag {
        item 'perl';
        item 'testing';
        item 'tdd';
    },
    'has all required tags regardless of order'
);

Subtests

perl

use v5.36;
use Test2::V0;

subtest 'User creation' => sub {
    my $user = User->new(name => 'Alice', email => 'alice@example.com');
    ok($user, 'user object created');
    is($user->name, 'Alice', 'name is set');
    is($user->email, 'alice@example.com', 'email is set');
};

subtest 'User validation' => sub {
    my $warnings = warns {
        User->new(name => '', email => 'bad');
    };
    ok($warnings, 'warns on invalid data');
};

done_testing;

Exception Testing with Test2

perl

use v5.36;
use Test2::V0;

# Test that code dies
like(
    dies { divide(10, 0) },
    qr/Division by zero/,
    'dies on division by zero'
);

# Test that code lives
ok(lives { divide(10, 2) }, 'division succeeds') or note($@);

# Combined pattern
subtest 'error handling' => sub {
    ok(lives { parse_config('valid.json') }, 'valid config parses');
    like(
        dies { parse_config('missing.json') },
        qr/Cannot open/,
        'missing file dies with message'
    );
};

done_testing;

Test Organization and prove

Directory Structure

text

t/
├── 00-load.t              # Verify modules compile
├── 01-basic.t             # Core functionality
├── unit/
│   ├── config.t           # Unit tests by module
│   ├── user.t
│   └── util.t
├── integration/
│   ├── database.t
│   └── api.t
├── lib/
│   └── TestHelper.pm      # Shared test utilities
└── fixtures/
    ├── config.json        # Test data files
    └── users.csv

prove Commands

bash

# Run all tests
prove -l t/

# Verbose output
prove -lv t/

# Run specific test
prove -lv t/unit/user.t

# Recursive search
prove -lr t/

# Parallel execution (8 jobs)
prove -lr -j8 t/

# Run only failing tests from last run
prove -l --state=failed t/

# Colored output with timer
prove -l --color --timer t/

# TAP output for CI
prove -l --formatter TAP::Formatter::JUnit t/ > results.xml

.proverc Configuration

text

-l
--color
--timer
-r
-j4
--state=save

Fixtures and Setup/Teardown

Subtest Isolation

perl

use v5.36;
use Test2::V0;
use File::Temp qw(tempdir);
use Path::Tiny;

subtest 'file processing' => sub {
    # Setup
    my $dir = tempdir(CLEANUP => 1);
    my $file = path($dir, 'input.txt');
    $file->spew_utf8("line1\nline2\nline3\n");

    # Test
    my $result = process_file("$file");
    is($result->{line_count}, 3, 'counts lines');

    # Teardown happens automatically (CLEANUP => 1)
};

Shared Test Helpers

Place reusable helpers in t/lib/TestHelper.pm and load with use lib 't/lib'. Export factory functions like create_test_db(), create_temp_dir(), and fixture_path() via Exporter.

Mocking

Test::MockModule

perl

use v5.36;
use Test2::V0;
use Test::MockModule;

subtest 'mock external API' => sub {
    my $mock = Test::MockModule->new('MyApp::API');

    # Good: Mock returns controlled data
    $mock->mock(fetch_user => sub ($self, $id) {
        return { id => $id, name => 'Mock User', email => 'mock@test.com' };
    });

    my $api = MyApp::API->new;
    my $user = $api->fetch_user(42);
    is($user->{name}, 'Mock User', 'returns mocked user');

    # Verify call count
    my $call_count = 0;
    $mock->mock(fetch_user => sub { $call_count++; return {} });
    $api->fetch_user(1);
    $api->fetch_user(2);
    is($call_count, 2, 'fetch_user called twice');

    # Mock is automatically restored when $mock goes out of scope
};

# Bad: Monkey-patching without restoration
# *MyApp::API::fetch_user = sub { ... };  # NEVER — leaks across tests

For lightweight mock objects, use Test::MockObject to create injectable test doubles with ->mock() and verify calls with ->called_ok().

Coverage with Devel::Cover

Running Coverage

bash

# Basic coverage report
cover -test

# Or step by step
perl -MDevel::Cover -Ilib t/unit/user.t
cover

# HTML report
cover -report html
open cover_db/coverage.html

# Specific thresholds
cover -test -report text | grep 'Total'

# CI-friendly: fail under threshold
cover -test && cover -report text -select '^lib/' \
  | perl -ne 'if (/Total.*?(\d+\.\d+)/) { exit 1 if $1 < 80 }'

Integration Testing

Use in-memory SQLite for database tests, mock HTTP::Tiny for API tests.

perl

use v5.36;
use Test2::V0;
use DBI;

subtest 'database integration' => sub {
    my $dbh = DBI->connect('dbi:SQLite:dbname=:memory:', '', '', {
        RaiseError => 1,
    });
    $dbh->do('CREATE TABLE users (id INTEGER PRIMARY KEY, name TEXT)');

    $dbh->prepare('INSERT INTO users (name) VALUES (?)')->execute('Alice');
    my $row = $dbh->selectrow_hashref('SELECT * FROM users WHERE name = ?', undef, 'Alice');
    is($row->{name}, 'Alice', 'inserted and retrieved user');
};

done_testing;

Best Practices

DO

Follow TDD: Write tests before implementation (red-green-refactor)
Use Test2::V0: Modern assertions, better diagnostics
Use subtests: Group related assertions, isolate state
Mock external dependencies: Network, database, file system
Use `prove -l`: Always include lib/ in @INC
Name tests clearly: 'user login with invalid password fails'
Test edge cases: Empty strings, undef, zero, boundary values
Aim for 80%+ coverage: Focus on business logic paths
Keep tests fast: Mock I/O, use in-memory databases

DON'T

Don't test implementation: Test behavior and output, not internals
Don't share state between subtests: Each subtest should be independent
Don't skip `done_testing`: Ensures all planned tests ran
Don't over-mock: Mock boundaries only, not the code under test
Don't use `Test::More` for new projects: Prefer Test2::V0
Don't ignore test failures: All tests must pass before merge
Don't test CPAN modules: Trust libraries to work correctly
Don't write brittle tests: Avoid over-specific string matching

Quick Reference

Task	Command / Pattern
Run all tests	`prove -lr t/`
Run one test verbose	`prove -lv t/unit/user.t`
Parallel test run	`prove -lr -j8 t/`
Coverage report	`cover -test && cover -report html`
Test equality	`is($got, $expected, 'label')`
Deep comparison	`is($got, hash { field k => 'v'; etc() }, 'label')`
Test exception	`like(dies { ... }, qr/msg/, 'label')`
Test no exception	`ok(lives { ... }, 'label')`
Mock a method	`Test::MockModule->new('Pkg')->mock(m => sub { ... })`
Skip tests	`SKIP: { skip 'reason', $count unless $cond; ... }`
TODO tests	`TODO: { local $TODO = 'reason'; ... }`

Common Pitfalls

Forgetting `done_testing`

perl

# Bad: Test file runs but doesn't verify all tests executed
use Test2::V0;
is(1, 1, 'works');
# Missing done_testing — silent bugs if test code is skipped

# Good: Always end with done_testing
use Test2::V0;
is(1, 1, 'works');
done_testing;

Missing `-l` Flag

bash

# Bad: Modules in lib/ not found
prove t/unit/user.t
# Can't locate MyApp/User.pm in @INC

# Good: Include lib/ in @INC
prove -l t/unit/user.t

Over-Mocking

Mock the dependency, not the code under test. If your test only verifies that a mock returns what you told it to, it tests nothing.

Test Pollution

Use my variables inside subtests — never our — to prevent state leaking between tests.

Remember: Tests are your safety net. Keep them fast, focused, and independent. Use Test2::V0 for new projects, prove for running, and Devel::Cover for accountability.

사용 방법

시작 전 확인

Perl Testing Patterns

When to Activate

TDD Workflow

Test::More Fundamentals

Basic Assertions

SKIP and TODO

Test2::V0 Modern Framework

Why Test2?

Deep Comparison with Builders

Subtests

Exception Testing with Test2

Test Organization and prove

Directory Structure

prove Commands

.proverc Configuration

Fixtures and Setup/Teardown

Subtest Isolation

Shared Test Helpers

Mocking

Test::MockModule

Coverage with Devel::Cover

Running Coverage

Integration Testing

Best Practices

DO

DON'T

Quick Reference

Common Pitfalls

Forgetting done_testing

Missing -l Flag

Over-Mocking

Test Pollution

관련 작업

laravel-tdd

tdd-workflow

rea-ci-tests-audit

springboot-tdd

더 많은 Skills

scientific-thinking-literature-review

docker-patterns

agentic-engineering

backend-patterns

Forgetting `done_testing`

Missing `-l` Flag