test-dependency.md

title	Test Dependency
description	Test Dependency

Test Dependency

• Overview
• Using it() function
• Returning values
• Multiple dependencies

Overview

Tests often depend on a set of preconditions or events to happen before they run, otherwise they fail.

For example, you can only assert that users can edit their accounts if first you assert that an account can be created.

Pest provides the method depends() to indicate that a Child test depends on one or more Parent tests.

Let's see how it works:

test('Parent', function () {
    expect(true)->toBeTrue();

    $this->assertTrue(true);
});

test('Child', function () {
    expect(false)->toBeFalse();
})->depends('Parent');

In the example above, the Child test depends on the Parent test.

If the Parent test passes, the Child test will be executed:

   PASS  Tests\Unit\ExampleTest
  ✓ Parent
  ✓ Child

  Tests:  2 passed

However, if the Parent test fails, the Child test will be skipped with a user-friendly message.

test('Parent', function () {
    expect(true)->toBeFalse();
});

test('Child', function () {
    expect(false)->toBeFalse();
})->depends('Parent');

The example above results in:

   FAIL  Tests\Unit\ExampleTest
  ⨯ Parent
  ! Child → This test depends on "P\Tests\Unit\ExampleTest::Parent" which does not exist.

Using it() function

The it() function automatically appends "it" to the test name.

For this reason, you must add "it " when referencing the test name in depends().

it('is the Parent', function () {
    expect(true)->toBeTrue();
});

test('Child', function () {
    expect(false)->toBeFalse();
})->depends('it is the Parent');

Results is:

   PASS  Tests\Unit\ExampleTest
  ✓ it is the Parent
  ✓ Child

  Tests:  2 passed

Returning values

Parent tests may return values which will be accessible as function arguments in the Child test.

test('Parent', function () {
    expect(true)->toBeTrue();

    return 'coming from Parent';
});

test('Child', function ($parentValue) {
    var_dump(func_get_args());

    expect($parentValue)->toBe('coming from Parent');
})->depends('Parent');

Resulting in:

array(1) {
  [0] =>
  string(18) "coming from Parent"
}

   PASS  Tests\Unit\ExampleTest
  ✓ Parent
  ✓ Child

  Tests:  2 passed

Multiple dependencies

You may also add multiple dependencies to a test.

All parent tests must pass, and the value returned by each test will be accessible via function parameters in order of dependency.

test('Test A', function () {
    expect(true)->toBeTrue();

    return 'coming from Test A';
});

test('Test B', function () {
    expect(true)->toBeTrue();

    return 'coming from Test B';
});

test('Test C', function () {
    expect(true)->toBeTrue();

    return 'coming from Test C';
});

test('Last Test', function ($testA, $testC, $testB) {
    var_dump(func_get_args());

    expect($testA)->toBe('coming from Test A');
    expect($testC)->toBe('coming from Test C');
    expect($testB)->toBe('coming from Test B');
})->depends('Test A', 'Test C', 'Test B');

Resulting in:

array(3) {
  [0] =>
  string(18) "coming from Test A"
  [1] =>
  string(18) "coming from Test C"
  [2] =>
  string(18) "coming from Test B"
}

   PASS  Tests\Unit\ExampleTest
  ✓ Test C
  ✓ Test B
  ✓ Test A
  ✓ Last Test

  Tests:  4 passed

Next section: Skipping Tests →