Move Encoding class away from the Language namespace

Language\Encoding::__mbMimeEncode -> Convert\MimeEncode::__mbMimeEncode
Langauge\Encoding::checkConvertEncoding -> Check\Encoding::checkConvertEncoding
Langauge\Encoding::setErrorChar -> Check\Encoding::setErrorChar
Langauge\Encoding::getErrorChar -> Encoding::getErrorChar
Langauge\Encoding::convertEncoding -> Convert\Encoding::convertEncoding

Also fixed encoding check that not only a code point but a string can
also be used as a parameter.

Update phpunit tests and split them out for each class

Normal test page is still combined for all classes but updated to
correctly use each class

4dev/tests/CoreLibsConvertEncodingTest.php

@@ -0,0 +1,102 @@
+<?php
+
+declare(strict_types=1);
+
+namespace tests;
+
+use PHPUnit\Framework\TestCase;
+
+/**
+ * Test class for Convert\Encoding
+ * @coversDefaultClass \CoreLibs\Convert\Encoding
+ * @testdox \CoreLibs\Convert\Encoding method tests
+ */
+final class CoreLibsConvertEncodingTest extends TestCase
+{
+	/**
+	 * Undocumented function
+	 *
+	 * @return array
+	 */
+	public function convertEncodingProvider(): array
+	{
+		return [
+			// 0: original string
+			// 1: target encoding
+			// 2: optional source encoding
+			// 3: auto check (not used)
+			// 4: expected string
+			// 5: expected string encoding
+			'simple from UTF-8 to SJIS' => [
+				'input string',
+				'SJIS',
+				null,
+				null,
+				'input string',
+				'SJIS'
+			],
+			'kanji from UTF-8 to SJIS' => [
+				'日本語',
+				'SJIS',
+				null,
+				null,
+				'日本語',
+				'SJIS'
+			],
+			'kanji from UTF-8 to SJIS with source' => [
+				'日本語',
+				'SJIS',
+				'UTF-8',
+				null,
+				'日本語',
+				'SJIS'
+			],
+		];
+	}
+
+	/**
+	 * Undocumented function
+	 *
+	 * @covers ::convertEncoding
+	 * @dataProvider convertEncodingProvider
+	 * @testdox convert encoding $target_encoding, source: $source_encoding, auto: $auto_check [$_dataName]
+	 *
+	 * @param  string $input
+	 * @param  string $target_encoding
+	 * @param  string $source_encoding
+	 * @param  bool   $auto_check
+	 * @param  string $expected
+	 * @param  string $expected_encoding
+	 * @return void
+	 */
+	public function testConvertEncoding(
+		string $input,
+		string $target_encoding,
+		?string $source_encoding,
+		?bool $auto_check,
+		string $expected,
+		string $expected_encoding
+	): void {
+		if ($source_encoding === null and $auto_check === null) {
+			$string = \CoreLibs\Convert\Encoding::convertEncoding($input, $target_encoding);
+		} elseif ($auto_check === null) {
+			$string = \CoreLibs\Convert\Encoding::convertEncoding($input, $target_encoding, $source_encoding);
+		} else {
+			$string = \CoreLibs\Convert\Encoding::convertEncoding(
+				$input,
+				$target_encoding,
+				$source_encoding,
+				$auto_check
+			);
+		}
+		// because we can't store encoding in here anyway
+		$target = mb_convert_encoding($expected, $expected_encoding, 'UTF-8');
+		// print "IN: $input, $target_encoding\n";
+		$this->assertEquals(
+			$target,
+			$string
+		);
+	}
+}
+
+// __END__