Improve functional test for Find with maxAwaitTimeMS

This inserts an additional document so that we can assert that the first rewind and next calls do not block, while the last next does issue a getMore and block.

tests/Operation/FindFunctionalTest.php

@@ -148,22 +148,45 @@ class FindFunctionalTest extends FunctionalTestCase
         // Insert documents into the capped collection.
         $bulkWrite = new BulkWrite(['ordered' => true]);
         $bulkWrite->insert(['_id' => 1]);
+        $bulkWrite->insert(['_id' => 2]);
         $result = $this->manager->executeBulkWrite($this->getNamespace(), $bulkWrite);
 
         $operation = new Find($databaseName, $cappedCollectionName, [], ['cursorType' => Find::TAILABLE_AWAIT, 'maxAwaitTimeMS' => $maxAwaitTimeMS]);
         $cursor = $operation->execute($this->getPrimaryServer());
         $it = new \IteratorIterator($cursor);
 
-        /* Make sure we await results for at least maxAwaitTimeMS, since no new
-         * documents should be inserted to wake up the server's query thread.
-         * Also ensure that we don't wait too long (server default is one
-         * second). */
+        /* The initial query includes the one and only document in its result
+         * batch, so we should not expect a delay. */
+        $startTime = microtime(true);
         $it->rewind();
+        $duration = microtime(true) - $startTime;
+        $this->assertLessThan($maxAwaitTimeMS * 0.001, $duration);
+
+        $this->assertTrue($it->valid());
+        $this->assertSameDocument(['_id' => 1], $it->current());
+
+        /* Advancing again takes us to the last document of the result batch,
+         * but still should not issue a getMore */
+        $startTime = microtime(true);
         $it->next();
+        $duration = microtime(true) - $startTime;
+        $this->assertLessThan($maxAwaitTimeMS * 0.001, $duration);
+
+        $this->assertTrue($it->valid());
+        $this->assertSameDocument(['_id' => 2], $it->current());
+
+        /* Now that we've reached the end of the initial result batch, advancing
+         * again will issue a getMore. Expect to wait at least maxAwaitTimeMS,
+         * since no new documents should be inserted to wake up the server's
+         * query thread. Also ensure we don't wait too long (server default is
+         * one second). */
         $startTime = microtime(true);
         $it->next();
-        $this->assertGreaterThanOrEqual($maxAwaitTimeMS * 0.001, microtime(true) - $startTime);
-        $this->assertLessThan(0.5, microtime(true) - $startTime);
+        $duration = microtime(true) - $startTime;
+        $this->assertGreaterThanOrEqual($maxAwaitTimeMS * 0.001, $duration);
+        $this->assertLessThan(0.5, $duration);
+
+        $this->assertFalse($it->valid());
     }
 
     /**