diff --git a/tests/Doctrine/Tests/ORM/ORMInvalidArgumentExceptionTest.php b/tests/Doctrine/Tests/ORM/ORMInvalidArgumentExceptionTest.php
index b4d269078..dea8d4f77 100644
--- a/tests/Doctrine/Tests/ORM/ORMInvalidArgumentExceptionTest.php
+++ b/tests/Doctrine/Tests/ORM/ORMInvalidArgumentExceptionTest.php
@@ -58,4 +58,95 @@ class ORMInvalidArgumentExceptionTest extends TestCase
             [new \stdClass(), 'Entity name must be a string, object given'],
         ];
     }
+
+    /**
+     * @dataProvider newEntitiesFoundThroughRelationshipsErrorMessages
+     */
+    public function testNewEntitiesFoundThroughRelationships(array $newEntities, string $expectedMessage) : void
+    {
+        $exception = ORMInvalidArgumentException::newEntitiesFoundThroughRelationships($newEntities);
+
+        self::assertInstanceOf(ORMInvalidArgumentException::class, $exception);
+        self::assertSame($expectedMessage, $exception->getMessage());
+    }
+
+    public function newEntitiesFoundThroughRelationshipsErrorMessages() : array
+    {
+        $stringEntity3 = uniqid('entity3', true);
+        $entity1       = new \stdClass();
+        $entity2       = new \stdClass();
+        $entity3       = $this->getMockBuilder(\stdClass::class)->setMethods(['__toString'])->getMock();
+        $association1  = [
+            'sourceEntity' => 'foo1',
+            'fieldName'    => 'bar1',
+            'targetEntity' => 'baz1',
+        ];
+        $association2  = [
+            'sourceEntity' => 'foo2',
+            'fieldName'    => 'bar2',
+            'targetEntity' => 'baz2',
+        ];
+        $association3  = [
+            'sourceEntity' => 'foo3',
+            'fieldName'    => 'bar3',
+            'targetEntity' => 'baz3',
+        ];
+
+        $entity3->expects(self::any())->method('__toString')->willReturn($stringEntity3);
+
+        return [
+            'one entity found' => [
+                [
+                    [
+                        $association1,
+                        $entity1,
+                    ],
+                ],
+                'A new entity was found through the relationship \'foo1#bar1\' that was not configured to cascade '
+                . 'persist operations for entity: stdClass@' . spl_object_hash($entity1)
+                . '. To solve this issue: Either explicitly call EntityManager#persist() on this unknown entity '
+                . 'or configure cascade persist this association in the mapping for example '
+                . '@ManyToOne(..,cascade={"persist"}). If you cannot find out which entity causes the problem '
+                . 'implement \'baz1#__toString()\' to get a clue.',
+            ],
+            'two entities found' => [
+                [
+                    [
+                        $association1,
+                        $entity1,
+                    ],
+                    [
+                        $association2,
+                        $entity2,
+                    ],
+                ],
+                'Multiple non-persisted new entities were found through the given association graph:' . "\n\n"
+                . ' * A new entity was found through the relationship \'foo1#bar1\' that was not configured to '
+                . 'cascade persist operations for entity: stdClass@' . spl_object_hash($entity1) . '. '
+                . 'To solve this issue: Either explicitly call EntityManager#persist() on this unknown entity '
+                . 'or configure cascade persist this association in the mapping for example '
+                . '@ManyToOne(..,cascade={"persist"}). If you cannot find out which entity causes the problem '
+                . 'implement \'baz1#__toString()\' to get a clue.' . "\n"
+                . ' * A new entity was found through the relationship \'foo2#bar2\' that was not configured to '
+                . 'cascade persist operations for entity: stdClass@' . spl_object_hash($entity2) . '. To solve '
+                . 'this issue: Either explicitly call EntityManager#persist() on this unknown entity or '
+                . 'configure cascade persist this association in the mapping for example '
+                . '@ManyToOne(..,cascade={"persist"}). If you cannot find out which entity causes the problem '
+                . 'implement \'baz2#__toString()\' to get a clue.'
+            ],
+            'two entities found, one is stringable' => [
+                [
+                    [
+                        $association3,
+                        $entity3,
+                    ],
+                ],
+                'A new entity was found through the relationship \'foo3#bar3\' that was not configured to cascade '
+                . 'persist operations for entity: ' . $stringEntity3
+                . '. To solve this issue: Either explicitly call EntityManager#persist() on this unknown entity '
+                . 'or configure cascade persist this association in the mapping for example '
+                . '@ManyToOne(..,cascade={"persist"}).',
+            ],
+        ];
+    }
 }