Convert text between popular capitalization standards

TextCaseConverter.php

<?php
class TextCaseConverter
{
	const SNAKE_CASE = 1; //snake_case
	const SPINAL_CASE = 2; //spinal-case
	const TRAIN_CASE = 3; //Train-Case
	const UPPER_CAMEL_CASE = 5; //CamelCase
	const LOWER_CAMEL_CASE = 6; //camelCase
	const CAMEL_CASE = self::UPPER_CAMEL_CASE; //CamelCase
	const BLANK_CASE = 7; //blank case

	public static function convert($text, $from, $to)
	{
		switch ($from)
		{
			case self::LOWER_CAMEL_CASE:
			case self::UPPER_CAMEL_CASE:
				$trans = preg_split('/(^[^A-Z]+|[A-Z][^A-Z]+)/', $text, -1, PREG_SPLIT_NO_EMPTY | PREG_SPLIT_DELIM_CAPTURE);
				break;

			case self::SNAKE_CASE:
				$trans = explode('_', $text);
				break;

			case self::TRAIN_CASE:
			case self::SPINAL_CASE:
				$trans = explode('-', $text);
				break;

			case self::BLANK_CASE:
				$trans = preg_split('/\s+/', $text);
				break;

			default:
				throw new Exception('Unknown conversion source: ' . $from);
		}

		$trans = array_map('trim', $trans);
		$trans = array_filter($trans);

		switch ($to)
		{
			case self::SNAKE_CASE:
				return join('_', array_map('strtolower', $trans));

			case self::SPINAL_CASE:
				return join('-', array_map('strtolower', $trans));

			case self::TRAIN_CASE:
				return join('-', array_map('ucfirst', array_map('strtolower', $trans)));

			case self::UPPER_CAMEL_CASE:
				return join('', array_map('ucfirst', array_map('strtolower', $trans)));

			case self::LOWER_CAMEL_CASE:
				return lcfirst(join('', array_map('ucfirst', array_map('strtolower', $trans))));

			case self::BLANK_CASE:
				return join(' ', array_map('strtolower', $trans));

			default:
				throw new Exception('Unknown conversion target: ' . $to);
		}
	}
}

TextCaseConverter_test.php

<?php
include_once 'TextCaseConverter.php';

$tests =
[
	['TestTest', 'test test', TextCaseConverter::BLANK_CASE, TextCaseConverter::CAMEL_CASE],
	['TestTest', 'test test', TextCaseConverter::BLANK_CASE, TextCaseConverter::UPPER_CAMEL_CASE],
	['testTest', 'test test', TextCaseConverter::BLANK_CASE, TextCaseConverter::LOWER_CAMEL_CASE],
	['test_test', 'test test', TextCaseConverter::BLANK_CASE, TextCaseConverter::SNAKE_CASE],
	['test-test', 'test test', TextCaseConverter::BLANK_CASE, TextCaseConverter::SPINAL_CASE],
	['Test-Test', 'test test', TextCaseConverter::BLANK_CASE, TextCaseConverter::TRAIN_CASE],
	['test test', 'test test', TextCaseConverter::BLANK_CASE, TextCaseConverter::BLANK_CASE],

	['TestTest', 'TEST TEST', TextCaseConverter::BLANK_CASE, TextCaseConverter::CAMEL_CASE],
	['TestTest', 'TEST TEST', TextCaseConverter::BLANK_CASE, TextCaseConverter::UPPER_CAMEL_CASE],
	['testTest', 'TEST TEST', TextCaseConverter::BLANK_CASE, TextCaseConverter::LOWER_CAMEL_CASE],
	['test_test', 'TEST TEST', TextCaseConverter::BLANK_CASE, TextCaseConverter::SNAKE_CASE],
	['test-test', 'TEST TEST', TextCaseConverter::BLANK_CASE, TextCaseConverter::SPINAL_CASE],
	['Test-Test', 'TEST TEST', TextCaseConverter::BLANK_CASE, TextCaseConverter::TRAIN_CASE],
	['test test', 'TEST TEST', TextCaseConverter::BLANK_CASE, TextCaseConverter::BLANK_CASE],

	['test test test', 'TestTESTTest', TextCaseConverter::CAMEL_CASE, TextCaseConverter::BLANK_CASE],
	['test test test', 'testTESTTest', TextCaseConverter::CAMEL_CASE, TextCaseConverter::BLANK_CASE],
	['test test', 'test_test', TextCaseConverter::SNAKE_CASE, TextCaseConverter::BLANK_CASE],
	['test test', 'test-test', TextCaseConverter::SPINAL_CASE, TextCaseConverter::BLANK_CASE],
	['test test', 'test-test', TextCaseConverter::TRAIN_CASE, TextCaseConverter::BLANK_CASE],
	['test test', 'test test', TextCaseConverter::BLANK_CASE, TextCaseConverter::BLANK_CASE],
	['test test', "test\t\ttest", TextCaseConverter::BLANK_CASE, TextCaseConverter::BLANK_CASE],

	['test', '__test__', TextCaseConverter::SNAKE_CASE, TextCaseConverter::BLANK_CASE],
	['test', '--test--', TextCaseConverter::SPINAL_CASE, TextCaseConverter::BLANK_CASE],
	['test', '--test--', TextCaseConverter::TRAIN_CASE, TextCaseConverter::BLANK_CASE],
	['test', " test \t", TextCaseConverter::BLANK_CASE, TextCaseConverter::BLANK_CASE],
	['not really camel case', 'Not Really CamelCase', TextCaseConverter::CAMEL_CASE, TextCaseConverter::BLANK_CASE],
];

foreach ($tests as $testCase)
{
	list ($expectedOutput, $input, $from, $to) = $testCase;
	$output = TextCaseConverter::convert($input, $from, $to);
	if ($output != $expectedOutput)
	{
		echo 'convert(' . $input . ', ' . $from . ', ' . $to . ') == "' . $output . '" != "' . $expectedOutput . '"' . PHP_EOL;
		exit(1);
	}
}

echo 'ok' . PHP_EOL;
exit(0);