diff --git a/core/modules/simpletest/src/Tests/SimpleTestBrowserTest.php b/core/modules/simpletest/src/Tests/SimpleTestBrowserTest.php
index d45c5bb12c..cf0e0d1612 100644
--- a/core/modules/simpletest/src/Tests/SimpleTestBrowserTest.php
+++ b/core/modules/simpletest/src/Tests/SimpleTestBrowserTest.php
@@ -4,7 +4,6 @@
 
 use Drupal\Core\Url;
 use Drupal\simpletest\WebTestBase;
-use Drupal\Tests\simpletest\Functional\ThroughUITest;
 
 /**
  * Tests the WebTestBase internal browser.
@@ -117,35 +116,4 @@ public function testUserAgentValidation() {
     $this->assertResponse(403, 'Requesting https.php with a normal User-Agent fails.');
   }
 
-  /**
-   * Tests that PHPUnit and KernelTestBase tests work through the UI.
-   *
-   * @todo Move this to a BrowserTestBase test.
-   */
-  public function testTestingThroughUI() {
-    $this->drupalGet('admin/config/development/testing');
-    $this->assertTrue(strpos($this->drupalSettings['simpleTest']['images'][0], 'core/misc/menu-collapsed.png') > 0, 'drupalSettings contains a link to core/misc/menu-collapsed.png.');
-    // We can not test WebTestBase tests here since they require a valid .htkey
-    // to be created. However this scenario is covered by the testception of
-    // \Drupal\simpletest\Tests\SimpleTestTest.
-
-    $tests = [
-      // A KernelTestBase test.
-      'Drupal\KernelTests\KernelTestBaseTest',
-      // A PHPUnit unit test.
-      'Drupal\Tests\action\Unit\Menu\ActionLocalTasksTest',
-      // A PHPUnit functional test.
-      ThroughUITest::class,
-    ];
-
-    foreach ($tests as $test) {
-      $this->drupalGet('admin/config/development/testing');
-      $edit = [
-        "tests[$test]" => TRUE,
-      ];
-      $this->drupalPostForm(NULL, $edit, t('Run tests'));
-      $this->assertText('0 fails, 0 exceptions');
-    }
-  }
-
 }
diff --git a/core/modules/simpletest/src/Tests/UiPhpUnitOutputTest.php b/core/modules/simpletest/src/Tests/UiPhpUnitOutputTest.php
index 6d99ab5860..e032cef941 100644
--- a/core/modules/simpletest/src/Tests/UiPhpUnitOutputTest.php
+++ b/core/modules/simpletest/src/Tests/UiPhpUnitOutputTest.php
@@ -11,8 +11,6 @@
  * @group simpletest
  *
  * @see \Drupal\Tests\Listeners\SimpletestUiPrinter
- *
- * @todo Convert to BrowserTestBase test.
  */
 class UiPhpUnitOutputTest extends WebTestBase {
 
diff --git a/core/modules/simpletest/tests/src/Functional/SimpletestUiTest.php b/core/modules/simpletest/tests/src/Functional/SimpletestUiTest.php
new file mode 100644
index 0000000000..43fdd2b2fc
--- /dev/null
+++ b/core/modules/simpletest/tests/src/Functional/SimpletestUiTest.php
@@ -0,0 +1,64 @@
+<?php
+
+namespace Drupal\Tests\simpletest\Functional;
+
+use Drupal\Core\Url;
+use Drupal\KernelTests\KernelTestBaseTest;
+use Drupal\Tests\action\Unit\Menu\ActionLocalTasksTest;
+use Drupal\Tests\BrowserTestBase;
+
+/**
+ * Test various aspects of testing through the UI form.
+ *
+ * @group simpletest
+ */
+class SimpletestUiTest extends BrowserTestBase {
+
+  /**
+   * Modules to enable.
+   *
+   * @var string[]
+   */
+  public static $modules = ['simpletest'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp() {
+    parent::setUp();
+    $this->drupalLogin($this->createUser(['administer unit tests']));
+  }
+
+  /**
+   * Tests that unit, kernel, and functional tests work through the UI.
+   */
+  public function testTestingThroughUI() {
+    $url = Url::fromRoute('simpletest.test_form');
+    $assertion = $this->assertSession();
+
+    $this->drupalGet($url);
+    $settings = $this->getDrupalSettings();
+    $this->assertTrue(strpos($settings['simpleTest']['images'][0], 'core/misc/menu-collapsed.png') > 0, 'drupalSettings contains a link to core/misc/menu-collapsed.png.');
+
+    // We can not test WebTestBase tests here since they require a valid .htkey
+    // to be created. However this scenario is covered by the testception of
+    // \Drupal\simpletest\Tests\SimpleTestTest.
+    $tests = [
+      // A KernelTestBase test.
+      KernelTestBaseTest::class,
+      // A PHPUnit unit test.
+      ActionLocalTasksTest::class,
+      // A PHPUnit functional test.
+      ThroughUITest::class,
+    ];
+
+    foreach ($tests as $test) {
+      $edit = [
+        "tests[$test]" => TRUE,
+      ];
+      $this->drupalPostForm($url, $edit, t('Run tests'));
+      $assertion->pageTextContains('0 fails, 0 exceptions');
+    }
+  }
+
+}
diff --git a/core/modules/simpletest/tests/src/Unit/SimpletestUiPrinterTest.php b/core/modules/simpletest/tests/src/Unit/SimpletestUiPrinterTest.php
new file mode 100644
index 0000000000..03aeda66f0
--- /dev/null
+++ b/core/modules/simpletest/tests/src/Unit/SimpletestUiPrinterTest.php
@@ -0,0 +1,34 @@
+<?php
+
+namespace Drupal\Tests\simpletest\Unit;
+
+use Drupal\Tests\Listeners\SimpletestUiPrinter;
+use Drupal\Tests\UnitTestCase;
+
+/**
+ * @group simpletest
+ */
+class SimpletestUiPrinterTest extends UnitTestCase {
+
+
+  public function provideBuffer() {
+    return [
+      ['&amp;&quot;&#039;&lt;&gt;', '&"\'<>'],
+      ['<a href="http:////www.example.com" target="_blank" title="http:////www.example.com">http:////www.example.com</a>', 'http:////www.example.com'],
+      ['this is some text <a href="http://www.example.com/" target="_blank" title="http://www.example.com/">http://www.example.com/</a> with a link in it.', 'this is some text http://www.example.com/ with a link in it.'],
+      ["HTML output was generated<br />\n", "HTML output was generated\n"],
+    ];
+  }
+
+  /**
+   * @dataProvider provideBuffer
+   */
+  public function testWrite($expected, $buffer) {
+    $printer = new SimpletestUiPrinter();
+    // Set up our expectation.
+    $this->expectOutputString($expected);
+    // Write the buffer.
+    $printer->write($buffer);
+  }
+
+}
diff --git a/core/tests/Drupal/Tests/Listeners/Legacy/HtmlOutputPrinter.php b/core/tests/Drupal/Tests/Listeners/Legacy/HtmlOutputPrinter.php
index 7c1f45e38f..53bb0e2347 100644
--- a/core/tests/Drupal/Tests/Listeners/Legacy/HtmlOutputPrinter.php
+++ b/core/tests/Drupal/Tests/Listeners/Legacy/HtmlOutputPrinter.php
@@ -15,7 +15,7 @@ class HtmlOutputPrinter extends \PHPUnit_TextUI_ResultPrinter {
   /**
    * {@inheritdoc}
    */
-  public function __construct($out, $verbose, $colors, $debug, $numberOfColumns) {
+  public function __construct($out = null, $verbose = false, $colors = self::COLOR_DEFAULT, $debug = false, $numberOfColumns = 80) {
     parent::__construct($out, $verbose, $colors, $debug, $numberOfColumns);
 
     $this->setUpHtmlOutput();