diff --git a/modules/opencase_defaults/tests/src/Functional/LoadTest.php b/modules/opencase_defaults/tests/src/Functional/LoadTest.php
deleted file mode 100644
index d76f7a3..0000000
--- a/modules/opencase_defaults/tests/src/Functional/LoadTest.php
+++ /dev/null
@@ -1,46 +0,0 @@
-<?php
-
-namespace Drupal\Tests\opencase_defaults\Functional;
-
-use Drupal\Core\Url;
-use Drupal\Tests\BrowserTestBase;
-
-/**
- * Simple test to ensure that main page loads with module enabled.
- *
- * @group opencase_defaults
- */
-class LoadTest extends BrowserTestBase {
-
-  /**
-   * Modules to enable.
-   *
-   * @var array
-   */
-  public static $modules = ['opencase_defaults'];
-
-  /**
-   * A user with permission to administer site configuration.
-   *
-   * @var \Drupal\user\UserInterface
-   */
-  protected $user;
-
-  /**
-   * {@inheritdoc}
-   */
-  protected function setUp() {
-    parent::setUp();
-    $this->user = $this->drupalCreateUser(['administer site configuration']);
-    $this->drupalLogin($this->user);
-  }
-
-  /**
-   * Tests that the home page loads with a 200 response.
-   */
-  public function testLoad() {
-    $this->drupalGet(Url::fromRoute('<front>'));
-    $this->assertSession()->statusCodeEquals(200);
-  }
-
-}
diff --git a/modules/opencase_entities/tests/src/Functional/LoadTest.php b/modules/opencase_entities/tests/src/Functional/LoadTest.php
deleted file mode 100644
index 2669263..0000000
--- a/modules/opencase_entities/tests/src/Functional/LoadTest.php
+++ /dev/null
@@ -1,46 +0,0 @@
-<?php
-
-namespace Drupal\Tests\opencase_entities\Functional;
-
-use Drupal\Core\Url;
-use Drupal\Tests\BrowserTestBase;
-
-/**
- * Simple test to ensure that main page loads with module enabled.
- *
- * @group opencase_entities
- */
-class LoadTest extends BrowserTestBase {
-
-  /**
-   * Modules to enable.
-   *
-   * @var array
-   */
-  public static $modules = ['opencase_entities'];
-
-  /**
-   * A user with permission to administer site configuration.
-   *
-   * @var \Drupal\user\UserInterface
-   */
-  protected $user;
-
-  /**
-   * {@inheritdoc}
-   */
-  protected function setUp() {
-    parent::setUp();
-    $this->user = $this->drupalCreateUser(['administer site configuration']);
-    $this->drupalLogin($this->user);
-  }
-
-  /**
-   * Tests that the home page loads with a 200 response.
-   */
-  public function testLoad() {
-    $this->drupalGet(Url::fromRoute('<front>'));
-    $this->assertSession()->statusCodeEquals(200);
-  }
-
-}
diff --git a/src/TimeBasedFieldUpdater.php b/src/TimeBasedFieldUpdater.php
index 2195946..731ac37 100644
--- a/src/TimeBasedFieldUpdater.php
+++ b/src/TimeBasedFieldUpdater.php
@@ -2,23 +2,27 @@
 
 namespace Drupal\opencase;
 use Drupal;
+use Drupal\Core\Entity\EntityTypeManagerInterface;
 
 final class TimeBasedFieldUpdater {
+
+    private EntityTypeManagerInterface $entityTypeManager;
     private string $date_field;
     private string $entity_type;
     private array $conditions;
     private string $date_format;
 
-    final public function __construct($entity_type, $date_field, $conditions = [], $date_format = 'Y-m-d')
-    {
+    final public function __construct(EntityTypeManagerInterface $entityTypeManager, string $entity_type, string $date_field, array $conditions = [], string $date_format = 'Y-m-d')
+    {   
+        $this->entityTypeManager = $entityTypeManager;
         $this->date_field = $date_field;
         $this->conditions = $conditions;
         $this->date_format = $date_format;
         $this->entity_type = $entity_type;
     }
 
-    final public function update($time_elapsed, $old_values, $new_values): void {
-        $query = Drupal::entityQuery($this->entity_type);
+    final public function update(string $time_elapsed, array $old_values, array $new_values): void {
+        $query = $this->entityTypeManager->getStorage($this->entity_type)->getQuery();
         foreach($this->conditions as $cond_field=>$cond_value) {
             $query->condition($cond_field, $cond_value);
         }
@@ -27,9 +31,9 @@ final class TimeBasedFieldUpdater {
         }
         $query->condition($this->date_field, date($this->date_format, strtotime('-'.$time_elapsed)), "<");
         foreach($query->execute() as $id) {
-            $entity = Drupal::entityTypeManager()->getStorage($this->entity_type)->load($id);
+            $entity = $this->entityTypeManager->getStorage($this->entity_type)->load($id);
             foreach($new_values as $new_field=>$new_value) {
-                $entity->set($new_field, $new_value); 
+                $entity->$new_field = $new_value; 
             }
             $entity->save();
         }      
diff --git a/tests/src/Functional/LoadTest.php b/tests/src/Functional/LoadTest.php
deleted file mode 100644
index 87ac8af..0000000
--- a/tests/src/Functional/LoadTest.php
+++ /dev/null
@@ -1,46 +0,0 @@
-<?php
-
-namespace Drupal\Tests\opencase\Functional;
-
-use Drupal\Core\Url;
-use Drupal\Tests\BrowserTestBase;
-
-/**
- * Simple test to ensure that main page loads with module enabled.
- *
- * @group opencase
- */
-class LoadTest extends BrowserTestBase {
-
-  /**
-   * Modules to enable.
-   *
-   * @var array
-   */
-  public static $modules = ['opencase'];
-
-  /**
-   * A user with permission to administer site configuration.
-   *
-   * @var \Drupal\user\UserInterface
-   */
-  protected $user;
-
-  /**
-   * {@inheritdoc}
-   */
-  protected function setUp() {
-    parent::setUp();
-    $this->user = $this->drupalCreateUser(['administer site configuration']);
-    $this->drupalLogin($this->user);
-  }
-
-  /**
-   * Tests that the home page loads with a 200 response.
-   */
-  public function testLoad() {
-    $this->drupalGet(Url::fromRoute('<front>'));
-    $this->assertSession()->statusCodeEquals(200);
-  }
-
-}
diff --git a/tests/src/Unit/TimeBasedFieldUpdaterTest.php b/tests/src/Unit/TimeBasedFieldUpdaterTest.php
new file mode 100644
index 0000000..19d6c92
--- /dev/null
+++ b/tests/src/Unit/TimeBasedFieldUpdaterTest.php
@@ -0,0 +1,35 @@
+<?php declare(strict_types = 1);
+
+namespace Drupal\Tests\opencase\Unit;
+
+use Drupal\Tests\UnitTestCase;
+use Drupal\opencase\TimeBasedFieldUpdater;
+
+class TimeBasedFieldUpdaterTest extends UnitTestCase{
+
+    function setUp():void {
+        $this->entityTypeManager = $this->getMockBuilder('\\Drupal\\Core\\Entity\\EntityTypeManager')->disableOriginalConstructor()->getMock();
+        $this->storage = $this->getMockBuilder('\\Drupal\\Core\\Entity\\EntityStorageInterface')->getMock();
+        $this->query = $this->getMockBuilder('\\Drupal\\Core\\Entity\\Query\\QueryInterface')->getMock();
+        $this->entityTypeManager->method('getStorage')->willReturn($this->storage);
+        $this->storage->method('getQuery')->willReturn($this->query);
+    }
+    function testFieldIsUpdatedOnEntityReturnedByQuery():void {
+        $this->query->method('execute')->willReturn([1]);
+        $this->entity = $this->getMockBuilder('\\Drupal\\Core\\Entity\\EntityBase')->disableOriginalConstructor()->getMock();
+        $this->storage->expects($this->once())->method('load')->with(1)->willReturn($this->entity); 
+        $updater = new TimeBasedFieldUpdater($this->entityTypeManager, 'dummy_entity', 'dummy_date_field');
+        $updater->update('3 months', ['dummy_status_field' => 3], ['dummy_status_field' => 4]);
+        $this->assertEquals($this->entity->dummy_status_field, 4);
+    }
+    function testFieldIsUpdatedOnAllEntitiesReturnedByQuery():void {
+        $this->query->method('execute')->willReturn([1, 2]);
+        $this->entity = $this->getMockBuilder('\\Drupal\\Core\\Entity\\EntityBase')->disableOriginalConstructor()->getMock();
+        $this->entity2 = $this->getMockBuilder('\\Drupal\\Core\\Entity\\EntityBase')->disableOriginalConstructor()->getMock();
+        $this->storage->method('load')->willReturnMap([[1, $this->entity], [2, $this-> entity2]]); 
+        $updater = new TimeBasedFieldUpdater($this->entityTypeManager, 'dummy_entity', 'dummy_date_field');
+        $updater->update('3 months', ['dummy_status_field' => 3], ['dummy_status_field' => 4]);
+        $this->assertEquals($this->entity->dummy_status_field, 4);  
+        $this->assertEquals($this->entity2->dummy_status_field, 4);     
+    }
+}
\ No newline at end of file