Use approximate pivot for maxAwaitTimeMS assertions

Since maxAwaitTimeMS is not a hard limit (the server may reply sooner), this will help avoid fragile test failures.

tests/Operation/FindFunctionalTest.php

@@ -154,7 +154,12 @@ class FindFunctionalTest extends FunctionalTestCase
             $this->markTestSkipped('maxAwaitTimeMS option is not supported');
         }
 
-        $maxAwaitTimeMS = 10;
+        $maxAwaitTimeMS = 100;
+
+        /* Calculate an approximate pivot to use for time assertions. We will
+         * assert that the duration of blocking responses is greater than this
+         * value, and vice versa. */
+        $pivot = ($maxAwaitTimeMS * 0.001) * 0.9;
 
         // Create a capped collection.
         $databaseName = $this->getDatabaseName();
@@ -183,7 +188,7 @@ class FindFunctionalTest extends FunctionalTestCase
         $startTime = microtime(true);
         $it->rewind();
         $duration = microtime(true) - $startTime;
-        $this->assertLessThan($maxAwaitTimeMS * 0.001, $duration);
+        $this->assertLessThan($pivot, $duration);
 
         $this->assertTrue($it->valid());
         $this->assertSameDocument(['_id' => 1], $it->current());
@@ -193,7 +198,7 @@ class FindFunctionalTest extends FunctionalTestCase
         $startTime = microtime(true);
         $it->next();
         $duration = microtime(true) - $startTime;
-        $this->assertLessThan($maxAwaitTimeMS * 0.001, $duration);
+        $this->assertLessThan($pivot, $duration);
 
         $this->assertTrue($it->valid());
         $this->assertSameDocument(['_id' => 2], $it->current());
@@ -206,7 +211,7 @@ class FindFunctionalTest extends FunctionalTestCase
         $startTime = microtime(true);
         $it->next();
         $duration = microtime(true) - $startTime;
-        $this->assertGreaterThanOrEqual($maxAwaitTimeMS * 0.001, $duration);
+        $this->assertGreaterThan($pivot, $duration);
         $this->assertLessThan(0.5, $duration);
 
         $this->assertFalse($it->valid());

tests/Operation/WatchFunctionalTest.php

@@ -380,6 +380,11 @@ class WatchFunctionalTest extends FunctionalTestCase
          * ensure we see the write. */
         $maxAwaitTimeMS = 100;
 
+        /* Calculate an approximate pivot to use for time assertions. We will
+         * assert that the duration of blocking responses is greater than this
+         * value, and vice versa. */
+        $pivot = ($maxAwaitTimeMS * 0.001) * 0.9;
+
         $operation = new Watch($this->manager, $this->getDatabaseName(), $this->getCollectionName(), [], ['maxAwaitTimeMS' => $maxAwaitTimeMS]);
         $changeStream = $operation->execute($this->getPrimaryServer());
 
@@ -391,7 +396,7 @@ class WatchFunctionalTest extends FunctionalTestCase
         $startTime = microtime(true);
         $changeStream->rewind();
         $duration = microtime(true) - $startTime;
-        $this->assertGreaterThanOrEqual($maxAwaitTimeMS * 0.001, $duration);
+        $this->assertGreaterThan($pivot, $duration);
         $this->assertLessThan(0.5, $duration);
 
         $this->assertFalse($changeStream->valid());
@@ -401,7 +406,7 @@ class WatchFunctionalTest extends FunctionalTestCase
         $startTime = microtime(true);
         $changeStream->next();
         $duration = microtime(true) - $startTime;
-        $this->assertGreaterThanOrEqual($maxAwaitTimeMS * 0.001, $duration);
+        $this->assertGreaterThan($pivot, $duration);
         $this->assertLessThan(0.5, $duration);
 
         $this->assertFalse($changeStream->valid());
@@ -413,7 +418,7 @@ class WatchFunctionalTest extends FunctionalTestCase
         $startTime = microtime(true);
         $changeStream->next();
         $duration = microtime(true) - $startTime;
-        $this->assertLessThan($maxAwaitTimeMS * 0.001, $duration);
+        $this->assertLessThan($pivot, $duration);
         $this->assertTrue($changeStream->valid());
     }