JSON assertions for PHPUnit

This library adds several new assertions to PHPUnit that allow you to easily and concisely verify complex data structures (often, but not necessarily, JSON documents) using JSONPath expressions and JSON schemas.

Author and copyright

Martin Helmich kontakt@martin-helmich.de
This library is MIT-licensed.

Installation

$ composer require --dev helmich/phpunit-json-assert

Compatibility

There are several release branches of this library, each of these being compatible with different releases of PHPUnit and PHP. The following table should give an easy overview:

"JSON assertion" version	PHPUnit 4	PHPUnit 5	PHPUnit 6	PHPUnit 7
v1 (branch v1), unsupported	✅	✅	🚫	🚫
v2 (branch master)	🚫	🚫	✅	✅

When you are using composer require and have already declared a dependency to phpunit/phpunit in your composer.json file, Composer should pick latest compatible version automatically.

Usage

Simply use the trait Helmich\JsonAssert\JsonAssertions in your test case. This trait offers a set of new assert* functions that you can use in your test cases:

<?php
use Helmich\JsonAssert\JsonAssertions;
use PHPUnit\Framework\TestCase;

class MyTestCase extends TestCase
{
  use JsonAssertions;

  public function testJsonDocumentIsValid()
  {
    $jsonDocument = [
      'id'          => 1000,
      'username'    => 'mhelmich',
      'given_name'  => 'Martin',
      'family_name' => 'Helmich',
      'age'         => 27,
      'hobbies'     => [
        "Heavy Metal",
        "Science Fiction",
        "Open Source Software"
      ]
    ];

    $this->assertJsonValueEquals($jsonDocument, '$.username', 'mhelmich');
    $this->assertJsonValueEquals($jsonDocument, '$.hobbies[*]', 'Open Source Software');
  }
}

Most assertions take a $jsonPath argument which may contain any kind of expression supported by the JSONPath library.

Alternatively, you can use the functional interface by including the file src/Functions.php into your test cases:

<?php
use Helmich\JsonAssert\JsonAssertions;
use PHPUnit\Framework\TestCase;

require_once('path/to/Functions.php');

class MyTestCase extends TestCase
{
  use JsonAssertions;

  public function testJsonDocumentIsValid()
  {
    $jsonDocument = [
      'id'          => 1000,
      'username'    => 'mhelmich',
      'given_name'  => 'Martin',
      'family_name' => 'Helmich',
      'age'         => 27,
      'hobbies'     => [
        "Heavy Metal",
        "Science Fiction",
        "Open Source Software"
      ]
    ];

    assertThat($jsonDocument, containsJsonValue('$.username', 'mhelmich'));
    assertThat($jsonDocument, matchesJsonConstraints([
        '$.given_name' => 'Martin',
        '$.age'        => greaterThanOrEqual(18),
        '$.hobbies'    => callback(function($a) { return count($a) > 2; })
    ]));
  }
}

Assertion reference

assertJsonValueEquals($doc, $jsonPath, $expected)

Asserts that the JSON value found in $doc at JSON path $jsonPath is equal to $expected.

assertJsonValueMatches($doc, $jsonPath, PHPUnit_Framework_Constraint $constraint)

Asserts that the JSON value found in $doc at JSON path $jsonPath matches the constraint $constraint.

Example:

$this->assertJsonValueMatches(
  $jsonDocument,
  '$.age',
  PHPUnit_Framework_Assert::greaterThanOrEqual(18)
);

assertJsonDocumentMatches($doc, $constraints)

Asserts that a variable number of JSON values match a constraint. $constraints is a key-value array in which JSON path expressions are used as keys to a constraint value.

Example:

$this->assertJsonDocumentMatches($jsonDocument, [
    '$.username' => 'mhelmich',
    '$.age'      => PHPUnit_Framework_Assert::greaterThanOrEqual(18)
]);

assertJsonDocumentMatchesSchema($doc, $schema)

Assert that a given JSON document matches a certain JSON schema.

Example:

$this->assertJsonDocumentMatchesSchema($jsonDocument, [
    'type'       => 'object',
    'required'   => ['username', 'age'],
    'properties' => [
        'username' => ['type' => 'string', 'minLength' => 3],
        'age'      => ['type' => 'number']
    ]
]);