diff --git a/core/modules/aggregator/tests/src/Functional/DeleteFeedTest.php b/core/modules/aggregator/tests/src/Functional/DeleteFeedTest.php
index 557720658d..9ab4960100 100644
--- a/core/modules/aggregator/tests/src/Functional/DeleteFeedTest.php
+++ b/core/modules/aggregator/tests/src/Functional/DeleteFeedTest.php
@@ -43,8 +43,12 @@ public function testDeleteFeed() {
     $this->assertResponse(404, 'Deleted feed source does not exist.');
 
     // Check database for feed.
-    $result = db_query("SELECT COUNT(*) FROM {aggregator_feed} WHERE title = :title AND url = :url", [':title' => $feed1->label(), ':url' => $feed1->getUrl()])->fetchField();
-    $this->assertFalse($result, 'Feed not found in database');
+    $result = \Drupal::entityQuery('aggregator_feed')
+      ->condition('title', $feed1->label())
+      ->condition('url', $feed1->getUrl())
+      ->count()
+      ->execute();
+    $this->assertEquals(0, $result, 'Feed not found in database');
   }
 
 }
diff --git a/core/modules/aggregator/tests/src/Functional/ImportOpmlTest.php b/core/modules/aggregator/tests/src/Functional/ImportOpmlTest.php
index e9037175ed..98b974a4c1 100644
--- a/core/modules/aggregator/tests/src/Functional/ImportOpmlTest.php
+++ b/core/modules/aggregator/tests/src/Functional/ImportOpmlTest.php
@@ -46,7 +46,8 @@ public function openImportForm() {
    * Submits form filled with invalid fields.
    */
   public function validateImportFormFields() {
-    $before = db_query('SELECT COUNT(*) FROM {aggregator_feed}')->fetchField();
+    $count_query = \Drupal::entityQuery('aggregator_feed')->count();
+    $before = $count_query->execute();
 
     $edit = [];
     $this->drupalPostForm('admin/config/services/aggregator/add/opml', $edit, t('Import'));
@@ -64,7 +65,7 @@ public function validateImportFormFields() {
     $this->drupalPostForm('admin/config/services/aggregator/add/opml', $edit, t('Import'));
     $this->assertText(t('The URL invalidUrl://empty is not valid.'), 'Error if the URL is invalid.');
 
-    $after = db_query('SELECT COUNT(*) FROM {aggregator_feed}')->fetchField();
+    $after = $count_query->execute();
     $this->assertEqual($before, $after, 'No feeds were added during the three last form submissions.');
   }
 
@@ -73,7 +74,8 @@ public function validateImportFormFields() {
    */
   protected function submitImportForm() {
     $connection = Database::getConnection();
-    $before = db_query('SELECT COUNT(*) FROM {aggregator_feed}')->fetchField();
+    $count_query = \Drupal::entityQuery('aggregator_feed')->count();
+    $before = $count_query->execute();
 
     $form['files[upload]'] = $this->getInvalidOpml();
     $this->drupalPostForm('admin/config/services/aggregator/add/opml', $form, t('Import'));
@@ -83,7 +85,7 @@ protected function submitImportForm() {
     $this->drupalPostForm('admin/config/services/aggregator/add/opml', $edit, t('Import'));
     $this->assertText(t('No new feed has been added.'), 'Attempting to load empty OPML from remote URL.');
 
-    $after = db_query('SELECT COUNT(*) FROM {aggregator_feed}')->fetchField();
+    $after = $count_query->execute();
     $this->assertEqual($before, $after, 'No feeds were added during the two last form submissions.');
 
     $connection->delete('aggregator_feed')->execute();
@@ -99,7 +101,7 @@ protected function submitImportForm() {
     $this->assertRaw(t('A feed with the URL %url already exists.', ['%url' => $feeds[0]['url[0][value]']]), 'Verifying that a duplicate URL was identified');
     $this->assertRaw(t('A feed named %title already exists.', ['%title' => $feeds[1]['title[0][value]']]), 'Verifying that a duplicate title was identified');
 
-    $after = db_query('SELECT COUNT(*) FROM {aggregator_feed}')->fetchField();
+    $after = $count_query->execute();
     $this->assertEqual($after, 2, 'Verifying that two distinct feeds were added.');
 
     $feeds_from_db = db_query("SELECT title, url, refresh FROM {aggregator_feed}");
diff --git a/core/modules/taxonomy/tests/src/Functional/TermIndexTest.php b/core/modules/taxonomy/tests/src/Functional/TermIndexTest.php
index 83ab04d5e1..2474e61247 100644
--- a/core/modules/taxonomy/tests/src/Functional/TermIndexTest.php
+++ b/core/modules/taxonomy/tests/src/Functional/TermIndexTest.php
@@ -88,9 +88,11 @@ protected function setUp() {
    */
   public function testTaxonomyIndex() {
     $node_storage = $this->container->get('entity.manager')->getStorage('node');
-    // Create terms in the vocabulary.
+    // Create terms in the vocabulary, and prepare count queries.
     $term_1 = $this->createTerm($this->vocabulary);
     $term_2 = $this->createTerm($this->vocabulary);
+    $count_query_1 = \Drupal::entityQuery('taxonomy_index')->condition('nid', $node->id())->condition('tid', $term_1->id())->count();
+    $count_query_2 = \Drupal::entityQuery('taxonomy_index')->condition('nid', $node->id())->condition('tid', $term_2->id())->count();
 
     // Post an article.
     $edit = [];
@@ -102,10 +104,7 @@ public function testTaxonomyIndex() {
 
     // Check that the term is indexed, and only once.
     $node = $this->drupalGetNodeByTitle($edit['title[0][value]']);
-    $index_count = db_query('SELECT COUNT(*) FROM {taxonomy_index} WHERE nid = :nid AND tid = :tid', [
-      ':nid' => $node->id(),
-      ':tid' => $term_1->id(),
-    ])->fetchField();
+    $index_count = $count_query_1->execute();
     $this->assertEqual(1, $index_count, 'Term 1 is indexed once.');
 
     // Update the article to change one term.
@@ -113,15 +112,9 @@ public function testTaxonomyIndex() {
     $this->drupalPostForm('node/' . $node->id() . '/edit', $edit, t('Save'));
 
     // Check that both terms are indexed.
-    $index_count = db_query('SELECT COUNT(*) FROM {taxonomy_index} WHERE nid = :nid AND tid = :tid', [
-      ':nid' => $node->id(),
-      ':tid' => $term_1->id(),
-    ])->fetchField();
+    $index_count = $count_query_1->execute();
     $this->assertEqual(1, $index_count, 'Term 1 is indexed.');
-    $index_count = db_query('SELECT COUNT(*) FROM {taxonomy_index} WHERE nid = :nid AND tid = :tid', [
-      ':nid' => $node->id(),
-      ':tid' => $term_2->id(),
-    ])->fetchField();
+    $index_count = $count_query_2->execute();
     $this->assertEqual(1, $index_count, 'Term 2 is indexed.');
 
     // Update the article to change another term.
@@ -129,15 +122,9 @@ public function testTaxonomyIndex() {
     $this->drupalPostForm('node/' . $node->id() . '/edit', $edit, t('Save'));
 
     // Check that only one term is indexed.
-    $index_count = db_query('SELECT COUNT(*) FROM {taxonomy_index} WHERE nid = :nid AND tid = :tid', [
-      ':nid' => $node->id(),
-      ':tid' => $term_1->id(),
-    ])->fetchField();
+    $index_count = $count_query_1->execute();
     $this->assertEqual(0, $index_count, 'Term 1 is not indexed.');
-    $index_count = db_query('SELECT COUNT(*) FROM {taxonomy_index} WHERE nid = :nid AND tid = :tid', [
-      ':nid' => $node->id(),
-      ':tid' => $term_2->id(),
-    ])->fetchField();
+    $index_count = $count_query_2->execute();
     $this->assertEqual(1, $index_count, 'Term 2 is indexed once.');
 
     // Redo the above tests without interface.
@@ -149,15 +136,9 @@ public function testTaxonomyIndex() {
     $node->save();
 
     // Check that the index was not changed.
-    $index_count = db_query('SELECT COUNT(*) FROM {taxonomy_index} WHERE nid = :nid AND tid = :tid', [
-      ':nid' => $node->id(),
-      ':tid' => $term_1->id(),
-    ])->fetchField();
+    $index_count = $count_query_1->execute();
     $this->assertEqual(0, $index_count, 'Term 1 is not indexed.');
-    $index_count = db_query('SELECT COUNT(*) FROM {taxonomy_index} WHERE nid = :nid AND tid = :tid', [
-      ':nid' => $node->id(),
-      ':tid' => $term_2->id(),
-    ])->fetchField();
+    $index_count = $count_query_2->execute();
     $this->assertEqual(1, $index_count, 'Term 2 is indexed once.');
 
     // Update the article to change one term.
@@ -165,15 +146,9 @@ public function testTaxonomyIndex() {
     $node->save();
 
     // Check that both terms are indexed.
-    $index_count = db_query('SELECT COUNT(*) FROM {taxonomy_index} WHERE nid = :nid AND tid = :tid', [
-      ':nid' => $node->id(),
-      ':tid' => $term_1->id(),
-    ])->fetchField();
+    $index_count = $count_query_1->execute();
     $this->assertEqual(1, $index_count, 'Term 1 is indexed.');
-    $index_count = db_query('SELECT COUNT(*) FROM {taxonomy_index} WHERE nid = :nid AND tid = :tid', [
-      ':nid' => $node->id(),
-      ':tid' => $term_2->id(),
-    ])->fetchField();
+    $index_count = $count_query_2->execute();
     $this->assertEqual(1, $index_count, 'Term 2 is indexed.');
 
     // Update the article to change another term.
@@ -181,15 +156,9 @@ public function testTaxonomyIndex() {
     $node->save();
 
     // Check that only one term is indexed.
-    $index_count = db_query('SELECT COUNT(*) FROM {taxonomy_index} WHERE nid = :nid AND tid = :tid', [
-      ':nid' => $node->id(),
-      ':tid' => $term_1->id(),
-    ])->fetchField();
+    $index_count = $count_query_1->execute();
     $this->assertEqual(1, $index_count, 'Term 1 is indexed once.');
-    $index_count = db_query('SELECT COUNT(*) FROM {taxonomy_index} WHERE nid = :nid AND tid = :tid', [
-      ':nid' => $node->id(),
-      ':tid' => $term_2->id(),
-    ])->fetchField();
+    $index_count = $count_query_2->execute();
     $this->assertEqual(0, $index_count, 'Term 2 is not indexed.');
   }