Simplify statements that throw exceptions

tests/Model/CachingIteratorTest.php

@@ -16,9 +16,10 @@ class CachingIteratorTest extends TestCase
     {
         $iterator = $this->getTraversable([1, 2, 3]);
         $this->assertSame([1, 2, 3], iterator_to_array($iterator));
+
         $this->expectException(Exception::class);
         $this->expectExceptionMessage('Cannot traverse an already closed generator');
-        $this->assertSame([1, 2, 3], iterator_to_array($iterator));
+        iterator_to_array($iterator);
     }
 
     public function testConstructorRewinds()

tests/Operation/CreateIndexesFunctionalTest.php

@@ -122,8 +122,9 @@ class CreateIndexesFunctionalTest extends FunctionalTestCase
         ];
 
         $operation = new CreateIndexes($this->getDatabaseName(), $this->getCollectionName(), $indexes);
+
         $this->expectException(RuntimeException::class);
-        $createdIndexNames = $operation->execute($this->getPrimaryServer());
+        $operation->execute($this->getPrimaryServer());
     }
 
     public function testDefaultWriteConcernIsOmitted()