class DrupalJSONTest

class DrupalJSONTest extends DrupalUnitTestCase {
    public static function getInfo() {
        return array(
            'name' => 'JSON',
            'description' => 'Perform unit tests on the drupal_json_encode() and drupal_json_decode() functions.',
            'group' => 'System',
        );
    }
    
    /**
     * Tests converting PHP variables to JSON strings and back.
     */
    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.');
    }

}