Add basic unit test

Author: dmolineus

tests/RectorPluginTest.php

@@ -0,0 +1,50 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Phpcq\PluginRectorTest;
+
+use Phpcq\PluginApi\Version10\Configuration\PluginConfigurationBuilderInterface;
+use Phpcq\PluginApi\Version10\Configuration\PluginConfigurationInterface;
+use Phpcq\PluginApi\Version10\DiagnosticsPluginInterface;
+use Phpcq\PluginApi\Version10\EnvironmentInterface;
+use PHPUnit\Framework\TestCase;
+
+/** @covers src/rector.php */
+final class RectorPluginTest extends TestCase
+{
+    private function instantiate(): DiagnosticsPluginInterface
+    {
+        return include dirname(__DIR__) . '/src/rector.php';
+    }
+
+    public function testPluginDescribesConfig(): void
+    {
+        $configOptionsBuilder = $this->getMockForAbstractClass(
+            PluginConfigurationBuilderInterface::class
+        );
+
+        $configOptionsBuilder->expects(self::once())
+            ->method('describeStringOption')
+            ->with('config', 'Path to config file');
+
+        $configOptionsBuilder->expects(self::once())
+            ->method('describeBoolOption')
+            ->with('dry-run', 'Only see the diff of changes, do not save them to files.');
+
+        $this->instantiate()->describeConfiguration($configOptionsBuilder);
+
+        // We assume it worked out as the plugin did execute correctly.
+        $this->addToAssertionCount(1);
+    }
+    public function testPluginCreatesDiagnosticTasks(): void
+    {
+        $config = $this->getMockForAbstractClass(PluginConfigurationInterface::class);
+        $environment = $this->getMockForAbstractClass(EnvironmentInterface::class);
+
+        $this->instantiate()->createDiagnosticTasks($config, $environment);
+
+        // We assume it worked out as the plugin did execute correctly.
+        $this->addToAssertionCount(1);
+    }
+}