Suppress risky test warnings in DocumentationExamplesTest

Author: jmikola

tests/DocumentationExamplesTest.php

@@ -1232,6 +1232,8 @@ public function testTransactions_intro_example_1()
     {
         $this->skipIfTransactionsAreNotSupported();
 
+        $this->assertNotNull('This test intentionally performs no assertions');
+
         $client = new Client(static::getUri());
 
         /* The WC is required: https://docs.mongodb.com/manual/core/transactions/#transactions-and-locks */
@@ -1392,6 +1394,8 @@ public function testTransactions_retry_example_3()
     {
         $this->skipIfTransactionsAreNotSupported();
 
+        $this->assertNotNull('This test intentionally performs no assertions');
+
         $client = new Client(static::getUri());
 
         /* The WC is required: https://docs.mongodb.com/manual/core/transactions/#transactions-and-locks */
@@ -1420,6 +1424,8 @@ function testCausalConsistency()
             $this->markTestSkipped('Secondary is not available');
         }
 
+        $this->assertNotNull('This test intentionally performs no assertions');
+
         // Prep
         $client = new Client(static::getUri());
         $items = $client->selectDatabase(