function DrupalJSONTest::testJSON in Drupal 7

Tests converting PHP variables to JSON strings and back.

File

modules/simpletest/tests/common.test, line 2962

Tests for common.inc functionality.

Class

DrupalJSONTest

Tests converting PHP variables to JSON strings and back.

Code

function testJSON() {

  // Setup a string with the full ASCII table.
  // @todo: Add tests for non-ASCII characters and Unicode.
  $str = '';
  for ($i = 0; $i < 128; $i++) {
    $str .= chr($i);
  }

  // Characters that must be escaped.
  // We check for unescaped " separately.
  $html_unsafe = array(
    '<',
    '>',
    '\'',
    '&',
  );

  // The following are the encoded forms of: < > ' & "
  $html_unsafe_escaped = array(
    '\\u003C',
    '\\u003E',
    '\\u0027',
    '\\u0026',
    '\\u0022',
  );

  // Verify there aren't character encoding problems with the source string.
  $this
    ->assertIdentical(strlen($str), 128, 'A string with the full ASCII table has the correct length.');
  foreach ($html_unsafe as $char) {
    $this
      ->assertTrue(strpos($str, $char) > 0, format_string('A string with the full ASCII table includes @s.', array(
      '@s' => $char,
    )));
  }

  // Verify that JSON encoding produces a string with all of the characters.
  $json = drupal_json_encode($str);
  $this
    ->assertTrue(strlen($json) > strlen($str), 'A JSON encoded string is larger than the source string.');

  // The first and last characters should be ", and no others.
  $this
    ->assertTrue($json[0] == '"', 'A JSON encoded string begins with ".');
  $this
    ->assertTrue($json[strlen($json) - 1] == '"', 'A JSON encoded string ends with ".');
  $this
    ->assertTrue(substr_count($json, '"') == 2, 'A JSON encoded string contains exactly two ".');

  // Verify that encoding/decoding is reversible.
  $json_decoded = drupal_json_decode($json);
  $this
    ->assertIdentical($str, $json_decoded, 'Encoding a string to JSON and decoding back results in the original string.');

  // Verify reversibility for structured data. Also verify that necessary
  // characters are escaped.
  $source = array(
    TRUE,
    FALSE,
    0,
    1,
    '0',
    '1',
    $str,
    array(
      'key1' => $str,
      'key2' => array(
        'nested' => TRUE,
      ),
    ),
  );
  $json = drupal_json_encode($source);
  foreach ($html_unsafe as $char) {
    $this
      ->assertTrue(strpos($json, $char) === FALSE, format_string('A JSON encoded string does not contain @s.', array(
      '@s' => $char,
    )));
  }

  // Verify that JSON encoding escapes the HTML unsafe characters
  foreach ($html_unsafe_escaped as $char) {
    $this
      ->assertTrue(strpos($json, $char) > 0, format_string('A JSON encoded string contains @s.', array(
      '@s' => $char,
    )));
  }
  $json_decoded = drupal_json_decode($json);
  $this
    ->assertNotIdentical($source, $json, 'An array encoded in JSON is not identical to the source.');
  $this
    ->assertIdentical($source, $json_decoded, 'Encoding structured data to JSON and decoding back results in the original data.');
}