1 files changed, 4 insertions, 6 deletions
diff --git a/jstests/libs/chunk_manipulation_util.js b/jstests/libs/chunk_manipulation_util.js
index 60037a46c04..b1e4d5a90e1 100644
--- a/jstests/libs/chunk_manipulation_util.js
+++ b/jstests/libs/chunk_manipulation_util.js
@@ -197,10 +197,8 @@ function configureMigrateFailPoint( shardConnection, stepNumber, mode ) {
 // Wait for moveChunk to reach a step (1 through 6).
 //
 function waitForMigrateStep( shardConnection, stepNumber ) {
-    var migrateThreadPrefix = 'migrateThread-';
-    var searchStringPrefix = 'step ' + stepNumber;
-
-    var admin = shardConnection.getDB('admin');
+    var searchString = 'step ' + stepNumber,
+        admin = shardConnection.getDB( 'admin' );
 
     assert( stepNumber >= 1);
     assert( stepNumber <= 5 );
@@ -216,8 +214,8 @@ function waitForMigrateStep( shardConnection, stepNumber ) {
         var in_progress = admin.currentOp(true).inprog;
         for ( var i = 0; i < in_progress.length; ++i ) {
             var op = in_progress[i];
-            if (op.desc && op.desc.startsWith(migrateThreadPrefix)) {
-                return op.msg.startsWith(searchStringPrefix);
+            if ( op.desc && op.desc === 'migrateThread' ) {
+                return op.msg.startsWith( searchString );
             }
         }