test: replace indexOf with includes

Start the transition to Array.prototype.includes() and
String.prototype.includes().  This commit refactors most of the
comparisons of Array.prototype.indexOf() and String.prototype.indexOf()
return values with -1 to the former methods in tests.

PR-URL: https://github.com/nodejs/node/pull/12604
Refs: https://github.com/nodejs/node/issues/12586
Reviewed-By: Alexey Orlenko <eaglexrlnk@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Gibson Fahnestock <gibfahn@gmail.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/test/parallel/test-stream-big-packet.js b/test/parallel/test-stream-big-packet.js
index 2ec69cf2cb..aeddfb2052 100644
--- a/test/parallel/test-stream-big-packet.js
+++ b/test/parallel/test-stream-big-packet.js
@@ -43,7 +43,7 @@ util.inherits(TestStream, stream.Transform);
 TestStream.prototype._transform = function(chunk, encoding, done) {
   if (!passed) {
     // Char 'a' only exists in the last write
-    passed = chunk.toString().indexOf('a') >= 0;
+    passed = chunk.toString().includes('a');
   }
   done();
 };