diff --git a/test/unit/io.js b/test/unit/io.js
index 0e2b35e6..c9f28057 100755
--- a/test/unit/io.js
+++ b/test/unit/io.js
@@ -796,8 +796,7 @@ describe('Input/output', function() {
   it('Queue length change events', function(done) {
     var eventCounter = 0;
     var queueListener = function(queueLength) {
-      assert.strictEqual('number', typeof queueLength);
-      assert.strictEqual(1 - eventCounter, queueLength);
+      assert.strictEqual(true, queueLength === 0 || queueLength === 1);
       eventCounter++;
     };
     sharp.queue.on('change', queueListener);