diff --git a/core/modules/taxonomy/src/Tests/TaxonomyTestTrait.php b/core/modules/taxonomy/src/Tests/TaxonomyTestTrait.php
index 744ab1b..1bac6c1 100644
--- a/core/modules/taxonomy/src/Tests/TaxonomyTestTrait.php
+++ b/core/modules/taxonomy/src/Tests/TaxonomyTestTrait.php
@@ -9,6 +9,9 @@
 
 /**
  * Provides common helper methods for Taxonomy module tests.
+ *
+ * @deprecated Scheduled for removal in Drupal 9.0.0.
+ *   Use \Drupal\Tests\taxonomy\Functional\TaxonomyTestTrait instead.
  */
 trait TaxonomyTestTrait {
 
diff --git a/core/modules/taxonomy/src/Tests/RssTest.php b/core/modules/taxonomy/tests/src/Functional/RssTest.php
similarity index 98%
rename from core/modules/taxonomy/src/Tests/RssTest.php
rename to core/modules/taxonomy/tests/src/Functional/RssTest.php
index 81a397d..be0d59d 100644
--- a/core/modules/taxonomy/src/Tests/RssTest.php
+++ b/core/modules/taxonomy/tests/src/Functional/RssTest.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Drupal\taxonomy\Tests;
+namespace Drupal\Tests\taxonomy\Functional;
 
 use Drupal\Core\Field\FieldStorageDefinitionInterface;
 use Drupal\views\Views;
diff --git a/core/modules/taxonomy/src/Tests/TaxonomyImageTest.php b/core/modules/taxonomy/tests/src/Functional/TaxonomyImageTest.php
similarity index 98%
rename from core/modules/taxonomy/src/Tests/TaxonomyImageTest.php
rename to core/modules/taxonomy/tests/src/Functional/TaxonomyImageTest.php
index 7d2ee2b..68e7adc 100644
--- a/core/modules/taxonomy/src/Tests/TaxonomyImageTest.php
+++ b/core/modules/taxonomy/tests/src/Functional/TaxonomyImageTest.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Drupal\taxonomy\Tests;
+namespace Drupal\Tests\taxonomy\Functional;
 
 use Drupal\field\Entity\FieldConfig;
 use Drupal\user\RoleInterface;
diff --git a/core/modules/taxonomy/src/Tests/TaxonomyQueryAlterTest.php b/core/modules/taxonomy/tests/src/Functional/TaxonomyQueryAlterTest.php
similarity index 97%
rename from core/modules/taxonomy/src/Tests/TaxonomyQueryAlterTest.php
rename to core/modules/taxonomy/tests/src/Functional/TaxonomyQueryAlterTest.php
index e5e787b..85310e9 100644
--- a/core/modules/taxonomy/src/Tests/TaxonomyQueryAlterTest.php
+++ b/core/modules/taxonomy/tests/src/Functional/TaxonomyQueryAlterTest.php
@@ -1,15 +1,15 @@
 <?php
 
-namespace Drupal\taxonomy\Tests;
+namespace Drupal\Tests\taxonomy\Functional;
 
-use Drupal\simpletest\WebTestBase;
+use Drupal\Tests\BrowserTestBase;
 
 /**
  * Tests that appropriate query tags are added.
  *
  * @group taxonomy
  */
-class TaxonomyQueryAlterTest extends WebTestBase {
+class TaxonomyQueryAlterTest extends BrowserTestBase {
 
   use TaxonomyTestTrait;
 
diff --git a/core/modules/taxonomy/src/Tests/TaxonomyTermIndentationTest.php b/core/modules/taxonomy/tests/src/Functional/TaxonomyTermIndentationTest.php
similarity index 98%
rename from core/modules/taxonomy/src/Tests/TaxonomyTermIndentationTest.php
rename to core/modules/taxonomy/tests/src/Functional/TaxonomyTermIndentationTest.php
index fbf8515..9bb6f9c 100644
--- a/core/modules/taxonomy/src/Tests/TaxonomyTermIndentationTest.php
+++ b/core/modules/taxonomy/tests/src/Functional/TaxonomyTermIndentationTest.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Drupal\taxonomy\Tests;
+namespace Drupal\Tests\taxonomy\Functional;
 
 /**
  * Ensure that the term indentation works properly.
diff --git a/core/modules/taxonomy/src/Tests/TaxonomyTermPagerTest.php b/core/modules/taxonomy/tests/src/Functional/TaxonomyTermPagerTest.php
similarity index 97%
rename from core/modules/taxonomy/src/Tests/TaxonomyTermPagerTest.php
rename to core/modules/taxonomy/tests/src/Functional/TaxonomyTermPagerTest.php
index f693988..66782f3 100644
--- a/core/modules/taxonomy/src/Tests/TaxonomyTermPagerTest.php
+++ b/core/modules/taxonomy/tests/src/Functional/TaxonomyTermPagerTest.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Drupal\taxonomy\Tests;
+namespace Drupal\Tests\taxonomy\Functional;
 
 /**
  * Ensures that the term pager works properly.
diff --git a/core/modules/taxonomy/tests/src/Functional/TaxonomyTestTrait.php b/core/modules/taxonomy/tests/src/Functional/TaxonomyTestTrait.php
new file mode 100644
index 0000000..db445e9
--- /dev/null
+++ b/core/modules/taxonomy/tests/src/Functional/TaxonomyTestTrait.php
@@ -0,0 +1,60 @@
+<?php
+
+namespace Drupal\Tests\taxonomy\Functional;
+
+use Drupal\Component\Utility\Unicode;
+use Drupal\Core\Language\LanguageInterface;
+use Drupal\taxonomy\Entity\Vocabulary;
+use Drupal\taxonomy\Entity\Term;
+
+/**
+ * Provides common helper methods for Taxonomy module tests.
+ */
+trait TaxonomyTestTrait {
+
+  /**
+   * Returns a new vocabulary with random properties.
+   */
+  public function createVocabulary() {
+    // Create a vocabulary.
+    $vocabulary = Vocabulary::create([
+      'name' => $this->randomMachineName(),
+      'description' => $this->randomMachineName(),
+      'vid' => Unicode::strtolower($this->randomMachineName()),
+      'langcode' => LanguageInterface::LANGCODE_NOT_SPECIFIED,
+      'weight' => mt_rand(0, 10),
+    ]);
+    $vocabulary->save();
+    return $vocabulary;
+  }
+
+  /**
+   * Returns a new term with random properties in vocabulary $vid.
+   *
+   * @param \Drupal\taxonomy\Entity\Vocabulary $vocabulary
+   *   The vocabulary object.
+   * @param array $values
+   *   (optional) An array of values to set, keyed by property name. If the
+   *   entity type has bundles, the bundle key has to be specified.
+   *
+   * @return \Drupal\taxonomy\Entity\Term
+   *   The new taxonomy term object.
+   */
+  public function createTerm(Vocabulary $vocabulary, $values = []) {
+    $filter_formats = filter_formats();
+    $format = array_pop($filter_formats);
+    $term = Term::create($values + [
+      'name' => $this->randomMachineName(),
+      'description' => [
+        'value' => $this->randomMachineName(),
+        // Use the first available text format.
+        'format' => $format->id(),
+      ],
+      'vid' => $vocabulary->id(),
+      'langcode' => LanguageInterface::LANGCODE_NOT_SPECIFIED,
+    ]);
+    $term->save();
+    return $term;
+  }
+
+}
diff --git a/core/modules/taxonomy/src/Tests/TaxonomyTranslationTestTrait.php b/core/modules/taxonomy/tests/src/Functional/TaxonomyTranslationTestTrait.php
similarity index 98%
rename from core/modules/taxonomy/src/Tests/TaxonomyTranslationTestTrait.php
rename to core/modules/taxonomy/tests/src/Functional/TaxonomyTranslationTestTrait.php
index 3607fc6..fc3cea7 100644
--- a/core/modules/taxonomy/src/Tests/TaxonomyTranslationTestTrait.php
+++ b/core/modules/taxonomy/tests/src/Functional/TaxonomyTranslationTestTrait.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Drupal\taxonomy\Tests;
+namespace Drupal\Tests\taxonomy\Functional;
 
 use Drupal\Core\Field\FieldStorageDefinitionInterface;
 use Drupal\field\Tests\EntityReference\EntityReferenceTestTrait;
diff --git a/core/modules/taxonomy/src/Tests/TermAutocompleteTest.php b/core/modules/taxonomy/tests/src/Functional/TermAutocompleteTest.php
similarity index 99%
rename from core/modules/taxonomy/src/Tests/TermAutocompleteTest.php
rename to core/modules/taxonomy/tests/src/Functional/TermAutocompleteTest.php
index 7ff519d..d90041b 100644
--- a/core/modules/taxonomy/src/Tests/TermAutocompleteTest.php
+++ b/core/modules/taxonomy/tests/src/Functional/TermAutocompleteTest.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Drupal\taxonomy\Tests;
+namespace Drupal\Tests\taxonomy\Functional;
 
 use Drupal\Component\Utility\Unicode;
 use Drupal\Core\Entity\Entity\EntityFormDisplay;
diff --git a/core/modules/taxonomy/src/Tests/TermTest.php b/core/modules/taxonomy/tests/src/Functional/TermTest.php
similarity index 99%
rename from core/modules/taxonomy/src/Tests/TermTest.php
rename to core/modules/taxonomy/tests/src/Functional/TermTest.php
index 42f92b1..e24a93a 100644
--- a/core/modules/taxonomy/src/Tests/TermTest.php
+++ b/core/modules/taxonomy/tests/src/Functional/TermTest.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Drupal\taxonomy\Tests;
+namespace Drupal\Tests\taxonomy\Functional;
 
 use Drupal\Component\Utility\Tags;
 use Drupal\Component\Utility\Unicode;
diff --git a/core/modules/taxonomy/src/Tests/TermTranslationTest.php b/core/modules/taxonomy/tests/src/Functional/TermTranslationTest.php
similarity index 98%
rename from core/modules/taxonomy/src/Tests/TermTranslationTest.php
rename to core/modules/taxonomy/tests/src/Functional/TermTranslationTest.php
index ccb16f6..8401b76 100644
--- a/core/modules/taxonomy/src/Tests/TermTranslationTest.php
+++ b/core/modules/taxonomy/tests/src/Functional/TermTranslationTest.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Drupal\taxonomy\Tests;
+namespace Drupal\Tests\taxonomy\Functional;
 
 use Drupal\Core\Url;
 use Drupal\system\Tests\Menu\AssertBreadcrumbTrait;
diff --git a/core/modules/taxonomy/src/Tests/TermTranslationUITest.php b/core/modules/taxonomy/tests/src/Functional/TermTranslationUITest.php
similarity index 99%
rename from core/modules/taxonomy/src/Tests/TermTranslationUITest.php
rename to core/modules/taxonomy/tests/src/Functional/TermTranslationUITest.php
index 43edc15..59da8c5 100644
--- a/core/modules/taxonomy/src/Tests/TermTranslationUITest.php
+++ b/core/modules/taxonomy/tests/src/Functional/TermTranslationUITest.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Drupal\taxonomy\Tests;
+namespace Drupal\Tests\taxonomy\Functional;
 
 use Drupal\content_translation\Tests\ContentTranslationUITestBase;
 use Drupal\Core\Language\LanguageInterface;
diff --git a/core/modules/taxonomy/src/Tests/ThemeTest.php b/core/modules/taxonomy/tests/src/Functional/ThemeTest.php
similarity index 97%
rename from core/modules/taxonomy/src/Tests/ThemeTest.php
rename to core/modules/taxonomy/tests/src/Functional/ThemeTest.php
index 8995c80..43ed72c 100644
--- a/core/modules/taxonomy/src/Tests/ThemeTest.php
+++ b/core/modules/taxonomy/tests/src/Functional/ThemeTest.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Drupal\taxonomy\Tests;
+namespace Drupal\Tests\taxonomy\Functional;
 
 /**
  * Verifies that various taxonomy pages use the expected theme.
diff --git a/core/modules/taxonomy/src/Tests/VocabularyUiTest.php b/core/modules/taxonomy/tests/src/Functional/VocabularyUiTest.php
similarity index 99%
rename from core/modules/taxonomy/src/Tests/VocabularyUiTest.php
rename to core/modules/taxonomy/tests/src/Functional/VocabularyUiTest.php
index 89c7a67..5417f2a 100644
--- a/core/modules/taxonomy/src/Tests/VocabularyUiTest.php
+++ b/core/modules/taxonomy/tests/src/Functional/VocabularyUiTest.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Drupal\taxonomy\Tests;
+namespace Drupal\Tests\taxonomy\Functional;
 use Drupal\Component\Utility\Unicode;
 
 use Drupal\Core\Url;