Resolves #4. Add fixer to replace ::className() method usages with ::class keyword.

tests/Fixer/LanguageConstruct/RemoveClassNameMethodUsagesFixerTest.php

@@ -0,0 +1,67 @@
+<?php
+declare(strict_types=1);
+
+namespace Ely\CS\Test\Fixer\Operator;
+
+use Ely\CS\Fixer\LanguageConstruct\RemoveClassNameMethodUsagesFixer;
+use PhpCsFixer\Tests\Test\AbstractFixerTestCase;
+
+/**
+ * @covers \Ely\CS\Fixer\LanguageConstruct\RemoveClassNameMethodUsagesFixer
+ */
+class RemoveClassNameMethodUsagesFixerTest extends AbstractFixerTestCase {
+
+    /**
+     * @param string      $expected
+     * @param null|string $input
+     *
+     * @dataProvider provideFixCases
+     */
+    public function testFix($expected, $input = null) {
+        $this->doTest($expected, $input);
+    }
+
+    public function provideFixCases() {
+        return [
+            [
+                '<?php echo className();',
+            ],
+            [
+                '<?php
+use Foo\Bar\Baz;
+
+$exceptionString = Baz::classname();
+',
+            ],
+            [
+                '<?php
+use Foo\Bar\Baz;
+
+$className = Baz::class;
+',
+                '<?php
+use Foo\Bar\Baz;
+
+$className = Baz::className();
+',
+            ],
+            [
+                '<?php
+use Foo\Bar\Baz;
+
+$exceptionString = "The class should be instance of " . Baz::class . " and nothing else";
+',
+                '<?php
+use Foo\Bar\Baz;
+
+$exceptionString = "The class should be instance of " . Baz::className() . " and nothing else";
+',
+            ],
+        ];
+    }
+
+    protected function createFixer() {
+        return new RemoveClassNameMethodUsagesFixer();
+    }
+
+}