only in patch2:
unchanged:
--- /dev/null
+++ b/core/modules/link/tests/src/Unit/Plugin/migrate/cckfield/LinkCckTest.php
@@ -0,0 +1,59 @@
+<?php
+
+namespace Drupal\Tests\link\Unit\Plugin\migrate\cckfield;
+
+use Drupal\migrate\Plugin\MigrationInterface;
+use Drupal\Tests\UnitTestCase;
+use Drupal\link\Plugin\migrate\cckfield\LinkField;
+use Prophecy\Argument;
+
+/**
+ * @coversDefaultClass \Drupal\link\Plugin\migrate\cckfield\LinkField
+ * @group link
+ */
+class LinkCckTest extends UnitTestCase {
+
+  /**
+   * @var \Drupal\migrate_drupal\Plugin\MigrateCckFieldInterface
+   */
+  protected $plugin;
+
+  /**
+   * @var \Drupal\migrate\Plugin\MigrationInterface
+   */
+  protected $migration;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp() {
+    $this->plugin = new LinkField([], 'link', []);
+
+    $migration = $this->prophesize(MigrationInterface::class);
+
+    // The plugin's processCckFieldValues() method will call
+    // mergeProcessOfProperty() and return nothing. So, in order to examine the
+    // process pipeline created by the plugin, we need to ensure that
+    // getProcess() always returns the last input to mergeProcessOfProperty().
+    $migration->mergeProcessOfProperty(Argument::type('string'), Argument::type('array'))
+      ->will(function($arguments) use ($migration) {
+        $migration->getProcess()->willReturn($arguments[1]);
+      });
+
+    $this->migration = $migration->reveal();
+  }
+
+  /**
+   * @covers ::processCckFieldValues
+   */
+  public function testProcessCckFieldValues() {
+    $this->plugin->processCckFieldValues($this->migration, 'somefieldname', []);
+
+    $expected = [
+      'plugin' => 'd6_cck_link',
+      'source' => 'somefieldname',
+    ];
+    $this->assertSame($expected, $this->migration->getProcess());
+  }
+
+}
only in patch2:
unchanged:
--- /dev/null
+++ b/core/modules/link/tests/src/Unit/Plugin/migrate/cckfield/d7/LinkCckTest.php
@@ -0,0 +1,65 @@
+<?php
+
+namespace Drupal\Tests\link\Unit\Plugin\migrate\cckfield\d7;
+
+use Drupal\migrate\Plugin\MigrationInterface;
+use Drupal\Tests\UnitTestCase;
+use Drupal\link\Plugin\migrate\cckfield\LinkField;
+use Prophecy\Argument;
+
+/**
+ * @coversDefaultClass \Drupal\link\Plugin\migrate\cckfield\d7\LinkField
+ * @group link
+ */
+class LinkCckTest extends UnitTestCase {
+
+  /**
+   * @var \Drupal\migrate_drupal\Plugin\MigrateCckFieldInterface
+   */
+  protected $plugin;
+
+  /**
+   * @var \Drupal\migrate\Plugin\MigrationInterface
+   */
+  protected $migration;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp() {
+    $this->plugin = new LinkField([], 'link', []);
+
+    $migration = $this->prophesize(MigrationInterface::class);
+
+    // The plugin's processFieldInstance() method will call
+    // mergeProcessOfProperty() and return nothing. So, in order to examine the
+    // process pipeline created by the plugin, we need to ensure that
+    // getProcess() always returns the last input to mergeProcessOfProperty().
+    $migration->mergeProcessOfProperty(Argument::type('string'), Argument::type('array'))
+      ->will(function($arguments) use ($migration) {
+        $migration->getProcess()->willReturn($arguments[1]);
+      });
+
+    $this->migration = $migration->reveal();
+  }
+
+  /**
+   * @covers ::processFieldInstance
+   */
+  public function testProcessFieldInstance() {
+      $this->plugin->processFieldInstance($this->migration);
+
+    $expected = [
+      'plugin' => 'static_map',
+      'source' => 'instance_settings/title',
+      'bypass' => TRUE,
+      'map' => [
+        'disabled' => DRUPAL_DISABLED,
+        'optional' => DRUPAL_OPTIONAL,
+        'required' => DRUPAL_REQUIRED,
+      ],
+    ];
+    $this->assertSame($expected, $this->migration->getProcess());
+  }
+
+}
only in patch2:
unchanged:
--- /dev/null
+++ b/core/modules/link/tests/src/Unit/Plugin/migrate/field/d6/LinkFieldTest.php
@@ -0,0 +1,59 @@
+<?php
+
+namespace Drupal\Tests\link\Unit\Plugin\migrate\field\d6;
+
+use Drupal\migrate\Plugin\MigrationInterface;
+use Drupal\Tests\UnitTestCase;
+use Drupal\link\Plugin\migrate\field\d6\LinkField;
+use Prophecy\Argument;
+
+/**
+ * @coversDefaultClass \Drupal\link\Plugin\migrate\field\d6\LinkField
+ * @group link
+ */
+class LinkFieldTest extends UnitTestCase {
+
+  /**
+   * @var \Drupal\migrate_drupal\Plugin\MigrateFieldInterface
+   */
+  protected $plugin;
+
+  /**
+   * @var \Drupal\migrate\Plugin\MigrationInterface
+   */
+  protected $migration;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp() {
+    $this->plugin = new LinkField([], 'link', []);
+
+    $migration = $this->prophesize(MigrationInterface::class);
+
+    // The plugin's processFieldValues() method will call
+    // mergeProcessOfProperty() and return nothing. So, in order to examine the
+    // process pipeline created by the plugin, we need to ensure that
+    // getProcess() always returns the last input to mergeProcessOfProperty().
+    $migration->mergeProcessOfProperty(Argument::type('string'), Argument::type('array'))
+      ->will(function($arguments) use ($migration) {
+        $migration->getProcess()->willReturn($arguments[1]);
+      });
+
+    $this->migration = $migration->reveal();
+  }
+
+  /**
+   * @covers ::processFieldValues
+   */
+  public function testProcessFieldValues() {
+    $this->plugin->processFieldValues($this->migration, 'somefieldname', []);
+
+    $expected = [
+      'plugin' => 'd6_field_link',
+      'source' => 'somefieldname',
+    ];
+    $this->assertSame($expected, $this->migration->getProcess());
+  }
+
+}
only in patch2:
unchanged:
--- /dev/null
+++ b/core/modules/link/tests/src/Unit/Plugin/migrate/field/d7/LinkFieldTest.php
@@ -0,0 +1,65 @@
+<?php
+
+namespace Drupal\Tests\link\Unit\Plugin\migrate\field\d7;
+
+use Drupal\migrate\Plugin\MigrationInterface;
+use Drupal\Tests\UnitTestCase;
+use Drupal\link\Plugin\migrate\field\d7\LinkField;
+use Prophecy\Argument;
+
+/**
+ * @coversDefaultClass \Drupal\link\Plugin\migrate\field\d7\LinkField
+ * @group link
+ */
+class LinkFieldTest extends UnitTestCase {
+
+  /**
+   * @var \Drupal\migrate_drupal\Plugin\MigrateFieldInterface
+   */
+  protected $plugin;
+
+  /**
+   * @var \Drupal\migrate\Plugin\MigrationInterface
+   */
+  protected $migration;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp() {
+    $this->plugin = new LinkField([], 'link', []);
+
+    $migration = $this->prophesize(MigrationInterface::class);
+
+    // The plugin's ProcessFieldInstance() method will call
+    // mergeProcessOfProperty() and return nothing. So, in order to examine the
+    // process pipeline created by the plugin, we need to ensure that
+    // getProcess() always returns the last input to mergeProcessOfProperty().
+    $migration->mergeProcessOfProperty(Argument::type('string'), Argument::type('array'))
+      ->will(function($arguments) use ($migration) {
+        $migration->getProcess()->willReturn($arguments[1]);
+      });
+
+    $this->migration = $migration->reveal();
+  }
+
+  /**
+   * @covers ::processFieldInstance
+   */
+  public function testProcessFieldInstance() {
+    $this->plugin->processFieldInstance($this->migration);
+
+    $expected = [
+      'plugin' => 'static_map',
+      'source' => 'instance_settings/title',
+      'bypass' => TRUE,
+      'map' => [
+        'disabled' => DRUPAL_DISABLED,
+        'optional' => DRUPAL_OPTIONAL,
+        'required' => DRUPAL_REQUIRED,
+      ],
+    ];
+    $this->assertSame($expected, $this->migration->getProcess());
+  }
+
+}