readline: simplify interface test code

test/parallel/test-readline-interface.js

@@ -179,15 +179,14 @@ function isWarned(emitter) {
   //   character
   fi = new FakeInput();
   rli = new readline.Interface({ input: fi, output: fi, terminal: true });
-  expectedLines = ['\t'];
-  callCount = 0;
+  called = false;
   rli.on('line', function(line) {
-    assert.equal(line, expectedLines[callCount]);
-    callCount++;
+    assert.equal(line, '\t');
+    called = true;
   });
   fi.emit('data', '\t');
   fi.emit('data', '\n');
-  assert.equal(callCount, expectedLines.length);
+  assert.ok(called);
   rli.close();
 
   // \t does not become part of the input when there is a completer function
@@ -201,15 +200,14 @@ function isWarned(emitter) {
     terminal: true,
     completer: completer
   });
-  expectedLines = ['foo'];
-  callCount = 0;
+  called = false;
   rli.on('line', function(line) {
-    assert.equal(line, expectedLines[callCount]);
-    callCount++;
+    assert.equal(line, 'foo');
+    called = true;
   });
   fi.emit('data', '\tfo\to\t');
   fi.emit('data', '\n');
-  assert.equal(callCount, expectedLines.length);
+  assert.ok(called);
   rli.close();
 
   // constructor throws if completer is not a function or undefined