Fixes #232: Drupal 9.0.x Symfony and PHPunit deprecation errors.

src/Event/MigratePrepareRowEvent.php

@@ -5,7 +5,7 @@ namespace Drupal\migrate_plus\Event;
 use Drupal\migrate\Plugin\MigrateSourceInterface;
 use Drupal\migrate\Plugin\MigrationInterface;
 use Drupal\migrate\Row;
-use Symfony\Component\EventDispatcher\Event;
+use Symfony\Contracts\EventDispatcher\Event;
 
 /**
  * Wraps a prepare-row event for event listeners.

tests/src/Kernel/Plugin/migrate_plus/data_parser/SimpleXmlTest.php

@@ -131,7 +131,7 @@ class SimpleXmlTest extends KernelTestBase {
     $url = $this->path . '/tests/data/simple_xml_broken_missing_tag.xml';
     $this->configuration['urls'][0] = $url;
     $this->expectException(MigrateException::class);
-    $this->expectExceptionMessageRegExp('/^Fatal Error 73/');
+    $this->expectExceptionMessageMatches('/^Fatal Error 73/');
     $parser = $this->pluginManager->createInstance('simple_xml', $this->configuration);
     $parser->next();
   }
@@ -146,7 +146,7 @@ class SimpleXmlTest extends KernelTestBase {
     $this->configuration['urls'][0] = $url;
 
     $this->expectException(MigrateException::class);
-    $this->expectExceptionMessageRegExp('/^Fatal Error 76/');
+    $this->expectExceptionMessageMatches('/^Fatal Error 76/');
 
     $parser = $this->pluginManager->createInstance('simple_xml', $this->configuration);
     $parser->next();
@@ -162,7 +162,7 @@ class SimpleXmlTest extends KernelTestBase {
     $this->configuration['urls'][0] = $url;
 
     $this->expectException(MigrateException::class);
-    $this->expectExceptionMessageRegExp('/^Fatal Error 46/');
+    $this->expectExceptionMessageMatches('/^Fatal Error 46/');
     $parser = $this->pluginManager->createInstance('simple_xml', $this->configuration);
     $parser->next();
   }

tests/src/Unit/DataParserPluginBaseTest.php

@@ -74,7 +74,7 @@ class DataParserPluginBaseTest extends MigrateTestCase {
 
     return $this->getMockBuilder(DataParserPluginBaseMock::class)
       ->setConstructorArgs([$configuration, $plugin_id, $plugin_definition])
-      ->setMethods(['openSourceUrl'])
+      ->onlyMethods(['openSourceUrl'])
       ->getMockForAbstractClass();
   }