class JsonTest

class JsonTest extends TestCase {
    
    /**
     * A test string with the full ASCII table.
     *
     * @var string
     */
    protected $string;
    
    /**
     * An array of unsafe html characters which has to be encoded.
     *
     * @var array
     */
    protected $htmlUnsafe;
    
    /**
     * An array of unsafe html characters which are already escaped.
     *
     * @var array
     */
    protected $htmlUnsafeEscaped;
    
    /**
     * {@inheritdoc}
     */
    protected function setUp() : void {
        parent::setUp();
        // Setup a string with the full ASCII table.
        // @todo: Add tests for non-ASCII characters and Unicode.
        $this->string = '';
        for ($i = 1; $i < 128; $i++) {
            $this->string .= chr($i);
        }
        // Characters that must be escaped.
        // We check for unescaped " separately.
        $this->htmlUnsafe = [
            '<',
            '>',
            '\'',
            '&',
        ];
        // The following are the encoded forms of: < > ' & "
        $this->htmlUnsafeEscaped = [
            '\\u003C',
            '\\u003E',
            '\\u0027',
            '\\u0026',
            '\\u0022',
        ];
    }
    
    /**
     * Tests encoding for every ASCII character.
     */
    public function testEncodingAscii() {
        // Verify there aren't character encoding problems with the source string.
        $this->assertSame(127, strlen($this->string), 'A string with the full ASCII table has the correct length.');
        foreach ($this->htmlUnsafe as $char) {
            $this->assertStringContainsString($char, $this->string, sprintf('A string with the full ASCII table includes %s.', $char));
        }
    }
    
    /**
     * Tests encoding length.
     */
    public function testEncodingLength() {
        // Verify that JSON encoding produces a string with all of the characters.
        $json = Json::encode($this->string);
        // Verify that a JSON-encoded string is larger than the source string.
        $this->assertGreaterThan(strlen($this->string), strlen($json));
    }
    
    /**
     * Tests end and start of the encoded string.
     */
    public function testEncodingStartEnd() {
        $json = Json::encode($this->string);
        // The first and last characters should be ", and no others.
        $this->assertStringStartsWith('"', $json, 'A JSON encoded string begins with ".');
        $this->assertStringEndsWith('"', $json, 'A JSON encoded string ends with ".');
        $this->assertSame(2, substr_count($json, '"'), 'A JSON encoded string contains exactly two ".');
    }
    
    /**
     * Tests converting PHP variables to JSON strings and back.
     */
    public function testReversibility() {
        $json = Json::encode($this->string);
        // Verify that encoding/decoding is reversible.
        $json_decoded = Json::decode($json);
        $this->assertSame($this->string, $json_decoded, 'Encoding a string to JSON and decoding back results in the original string.');
    }
    
    /**
     * Tests the reversibility of structured data.
     */
    public function testStructuredReversibility() {
        // Verify reversibility for structured data. Also verify that necessary
        // characters are escaped.
        $source = [
            TRUE,
            FALSE,
            0,
            1,
            '0',
            '1',
            $this->string,
            [
                'key1' => $this->string,
                'key2' => [
                    'nested' => TRUE,
                ],
            ],
        ];
        $json = Json::encode($source);
        foreach ($this->htmlUnsafe as $char) {
            $this->assertStringNotContainsString($char, $json, sprintf('A JSON encoded string does not contain %s.', $char));
        }
        // Verify that JSON encoding escapes the HTML unsafe characters
        foreach ($this->htmlUnsafeEscaped as $char) {
            $this->assertStringContainsString($char, $json, sprintf('A JSON encoded string contains %s.', $char));
        }
        $json_decoded = Json::decode($json);
        $this->assertNotSame($source, $json, 'An array encoded in JSON is identical to the source.');
        $this->assertSame($source, $json_decoded, 'Encoding structured data to JSON and decoding back not results in the original data.');
    }

}