trait ExpectDeprecationTrait

trait ExpectDeprecationTrait {
    
    /**
     * Sets up the test error handler.
     *
     * This method is run before each test's ::setUp() method, and when the
     * DeprecationHandler is active, resets the extension to be able to collect
     * the test's deprecations, and sets TestErrorHandler as the current error
     * handler.
     *
     * @see \Drupal\TestTools\ErrorHandler\TestErrorHandler
     */
    public function setUpErrorHandler() : void {
        if (!DeprecationHandler::isEnabled()) {
            return;
        }
        DeprecationHandler::reset();
        set_error_handler(new TestErrorHandler(Error::currentErrorHandler(), $this));
    }
    
    /**
     * Tears down the test error handler.
     *
     * This method is run after each test's ::tearDown() method, and checks if
     * collected deprecations match the expectations; it also resets the error
     * handler to the one set prior of the change made by ::setUpErrorHandler().
     */
    public function tearDownErrorHandler() : void {
        if (!DeprecationHandler::isEnabled()) {
            return;
        }
        // We expect that the current error handler is the one set by
        // ::setUpErrorHandler() prior to the start of the test execution. If not,
        // the error handler was changed during the test execution but not properly
        // restored during ::tearDown().
        $handler = Error::currentErrorHandler();
        if (!$handler instanceof TestErrorHandler) {
            throw new \RuntimeException(sprintf('%s registered its own error handler (%s) without restoring the previous one before or during tear down. This can cause unpredictable test results. Ensure the test cleans up after itself.', $this->name(), self::getCallableName($handler)));
        }
        restore_error_handler();
        // Checks if collected deprecations match the expectations.
        if (DeprecationHandler::getExpectedDeprecations()) {
            $prefix = "@expectedDeprecation:\n";
            $expDep = $prefix . '%A  ' . implode("\n%A  ", DeprecationHandler::getExpectedDeprecations()) . "\n%A";
            $actDep = $prefix . '  ' . implode("\n  ", DeprecationHandler::getCollectedDeprecations()) . "\n";
            $this->assertStringMatchesFormat($expDep, $actDep);
        }
    }
    
    /**
     * Adds an expected deprecation.
     *
     * @param string $message
     *   The expected deprecation message.
     */
    public function expectDeprecation(string $message) : void {
        if (!DeprecationHandler::isDeprecationTest($this)) {
            throw new \RuntimeException('expectDeprecation() can only be called from tests marked with #[IgnoreDeprecations] or \'@group legacy\'');
        }
        if (!DeprecationHandler::isEnabled()) {
            return;
        }
        DeprecationHandler::expectDeprecation($message);
    }
    
    /**
     * Returns a callable as a string suitable for inclusion in a message.
     *
     * @param callable $callable
     *   The callable.
     *
     * @return string
     *   The string suitable for inclusion in a message.
     *
     * @see https://stackoverflow.com/questions/34324576/print-name-or-definition-of-callable-in-php
     */
    private static function getCallableName(callable $callable) : string {
        switch (TRUE) {
            case is_string($callable) && strpos($callable, '::'):
                return '[static] ' . $callable;
            case is_string($callable):
                return '[function] ' . $callable;
            case is_array($callable) && is_object($callable[0]):
                return '[method] ' . get_class($callable[0]) . '->' . $callable[1];
            case is_array($callable):
                return '[static] ' . $callable[0] . '::' . $callable[1];
            case $callable instanceof \Closure:
                return '[closure]';
            case is_object($callable):
                return '[invokable] ' . get_class($callable);
            default:
                return '[unknown]';
        }
    }

}