diff --git a/core/modules/workflows/tests/src/Unit/WorkflowTest.php b/core/modules/workflows/tests/src/Unit/WorkflowTest.php
index b055fabcbde64b84bb0db1a6a43dc2871cb865c0..89ee31f6baae23849e9347d144e3036d8825e7a5 100644
--- a/core/modules/workflows/tests/src/Unit/WorkflowTest.php
+++ b/core/modules/workflows/tests/src/Unit/WorkflowTest.php
@@ -610,6 +610,22 @@ public function testSetTransitionFromStatesMissingState() {
     $workflow->setTransitionFromStates('create_new_draft', ['draft', 'published', 'archived']);
   }
 
+  /**
+   * @covers ::setTransitionFromStates
+   */
+  public function testSetTransitionFromStatesAlreadyExists() {
+    $this->setExpectedException(\InvalidArgumentException::class, "The 'create_new_draft' transition already allows 'draft' to 'draft' transitions in workflow 'test'");
+    $workflow = new Workflow(['id' => 'test', 'type' => 'test_type'], 'workflow');
+    $workflow
+      ->addState('draft', 'Draft')
+      ->addState('archived', 'Archived')
+      ->addState('needs_review', 'Needs Review')
+      ->addTransition('create_new_draft', 'Create new draft', ['draft'], 'draft')
+      ->addTransition('needs_review', 'Needs review', ['needs_review'], 'draft');
+
+    $workflow->setTransitionFromStates('needs_review', ['draft']);
+  }
+
   /**
    * @covers ::deleteTransition
    */