test: add block scoping to test-readline-interface

Use block-scoping in test-readline-interface to avoid side effects and
make tests more modular. (Some contain race conditions and will need to
be moved to the sequential directory if they can't be refactored to
avoid the race condition.)

PR-URL: https://github.com/nodejs/node/pull/14615
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Yuta Hiroto <hello@about-hiroppy.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

1 files changed, 402 insertions, 318 deletions

diff --git a/test/parallel/test-readline-interface.js b/test/parallel/test-readline-interface.js
index e73481d429..5d9f12cd55 100644
--- a/test/parallel/test-readline-interface.js
+++ b/test/parallel/test-readline-interface.js
@@ -87,177 +87,222 @@ function isWarned(emitter) {
 }
 
 [ true, false ].forEach(function(terminal) {
-  let fi;
-  let rli;
-  let called;
-
   // disable history
-  fi = new FakeInput();
-  rli = new readline.Interface({ input: fi, output: fi, terminal: terminal,
-                                 historySize: 0 });
-  assert.strictEqual(rli.historySize, 0);
+  {
+    const fi = new FakeInput();
+    const rli = new readline.Interface(
+      { input: fi, output: fi, terminal: terminal, historySize: 0 }
+    );
+    assert.strictEqual(rli.historySize, 0);
 
-  fi.emit('data', 'asdf\n');
-  assert.deepStrictEqual(rli.history, terminal ? [] : undefined);
-  rli.close();
+    fi.emit('data', 'asdf\n');
+    assert.deepStrictEqual(rli.history, terminal ? [] : undefined);
+    rli.close();
+  }
 
   // default history size 30
-  fi = new FakeInput();
-  rli = new readline.Interface({ input: fi, output: fi, terminal: terminal });
-  assert.strictEqual(rli.historySize, 30);
+  {
+    const fi = new FakeInput();
+    const rli = new readline.Interface(
+      { input: fi, output: fi, terminal: terminal }
+    );
+    assert.strictEqual(rli.historySize, 30);
 
-  fi.emit('data', 'asdf\n');
-  assert.deepStrictEqual(rli.history, terminal ? ['asdf'] : undefined);
-  rli.close();
+    fi.emit('data', 'asdf\n');
+    assert.deepStrictEqual(rli.history, terminal ? ['asdf'] : undefined);
+    rli.close();
+  }
 
   // sending a full line
-  fi = new FakeInput();
-  rli = new readline.Interface({ input: fi, output: fi, terminal: terminal });
-  called = false;
-  rli.on('line', function(line) {
-    called = true;
-    assert.strictEqual(line, 'asdf');
-  });
-  fi.emit('data', 'asdf\n');
-  assert.ok(called);
+  {
+    const fi = new FakeInput();
+    const rli = new readline.Interface(
+      { input: fi, output: fi, terminal: terminal }
+    );
+    let called = false;
+    rli.on('line', function(line) {
+      called = true;
+      assert.strictEqual(line, 'asdf');
+    });
+    fi.emit('data', 'asdf\n');
+    assert.ok(called);
+  }
 
   // sending a blank line
-  fi = new FakeInput();
-  rli = new readline.Interface({ input: fi, output: fi, terminal: terminal });
-  called = false;
-  rli.on('line', function(line) {
-    called = true;
-    assert.strictEqual(line, '');
-  });
-  fi.emit('data', '\n');
-  assert.ok(called);
+  {
+    const fi = new FakeInput();
+    const rli = new readline.Interface(
+      { input: fi, output: fi, terminal: terminal }
+    );
+    let called = false;
+    rli.on('line', function(line) {
+      called = true;
+      assert.strictEqual(line, '');
+    });
+    fi.emit('data', '\n');
+    assert.ok(called);
+  }
 
   // sending a single character with no newline
-  fi = new FakeInput();
-  rli = new readline.Interface(fi, {});
-  called = false;
-  rli.on('line', function(line) {
-    called = true;
-  });
-  fi.emit('data', 'a');
-  assert.ok(!called);
-  rli.close();
+  {
+    const fi = new FakeInput();
+    const rli = new readline.Interface(fi, {});
+    let called = false;
+    rli.on('line', function(line) {
+      called = true;
+    });
+    fi.emit('data', 'a');
+    assert.ok(!called);
+    rli.close();
+  }
 
   // sending a single character with no newline and then a newline
-  fi = new FakeInput();
-  rli = new readline.Interface({ input: fi, output: fi, terminal: terminal });
-  called = false;
-  rli.on('line', function(line) {
-    called = true;
-    assert.strictEqual(line, 'a');
-  });
-  fi.emit('data', 'a');
-  assert.ok(!called);
-  fi.emit('data', '\n');
-  assert.ok(called);
-  rli.close();
+  {
+    const fi = new FakeInput();
+    const rli = new readline.Interface(
+      { input: fi, output: fi, terminal: terminal }
+    );
+    let called = false;
+    rli.on('line', function(line) {
+      called = true;
+      assert.strictEqual(line, 'a');
+    });
+    fi.emit('data', 'a');
+    assert.ok(!called);
+    fi.emit('data', '\n');
+    assert.ok(called);
+    rli.close();
+  }
 
   // sending multiple newlines at once
-  fi = new FakeInput();
-  rli = new readline.Interface({ input: fi, output: fi, terminal: terminal });
-  let expectedLines = ['foo', 'bar', 'baz'];
-  let callCount = 0;
-  rli.on('line', function(line) {
-    assert.strictEqual(line, expectedLines[callCount]);
-    callCount++;
-  });
-  fi.emit('data', `${expectedLines.join('\n')}\n`);
-  assert.strictEqual(callCount, expectedLines.length);
-  rli.close();
+  {
+    const fi = new FakeInput();
+    const rli = new readline.Interface(
+      { input: fi, output: fi, terminal: terminal }
+    );
+    const expectedLines = ['foo', 'bar', 'baz'];
+    let callCount = 0;
+    rli.on('line', function(line) {
+      assert.strictEqual(line, expectedLines[callCount]);
+      callCount++;
+    });
+    fi.emit('data', `${expectedLines.join('\n')}\n`);
+    assert.strictEqual(callCount, expectedLines.length);
+    rli.close();
+  }
 
   // sending multiple newlines at once that does not end with a new line
-  fi = new FakeInput();
-  rli = new readline.Interface({ input: fi, output: fi, terminal: terminal });
-  expectedLines = ['foo', 'bar', 'baz', 'bat'];
-  callCount = 0;
-  rli.on('line', function(line) {
-    assert.strictEqual(line, expectedLines[callCount]);
-    callCount++;
-  });
-  fi.emit('data', expectedLines.join('\n'));
-  assert.strictEqual(callCount, expectedLines.length - 1);
-  rli.close();
+  {
+    const fi = new FakeInput();
+    const rli = new readline.Interface(
+      { input: fi, output: fi, terminal: terminal }
+    );
+    const expectedLines = ['foo', 'bar', 'baz', 'bat'];
+    let callCount = 0;
+    rli.on('line', function(line) {
+      assert.strictEqual(line, expectedLines[callCount]);
+      callCount++;
+    });
+    fi.emit('data', expectedLines.join('\n'));
+    assert.strictEqual(callCount, expectedLines.length - 1);
+    rli.close();
+  }
 
   // sending multiple newlines at once that does not end with a new(empty)
   // line and a `end` event
-  fi = new FakeInput();
-  rli = new readline.Interface({ input: fi, output: fi, terminal: terminal });
-  expectedLines = ['foo', 'bar', 'baz', ''];
-  callCount = 0;
-  rli.on('line', function(line) {
-    assert.strictEqual(line, expectedLines[callCount]);
-    callCount++;
-  });
-  rli.on('close', function() {
-    callCount++;
-  });
-  fi.emit('data', expectedLines.join('\n'));
-  fi.emit('end');
-  assert.strictEqual(callCount, expectedLines.length);
-  rli.close();
+  {
+    const fi = new FakeInput();
+    const rli = new readline.Interface(
+      { input: fi, output: fi, terminal: terminal }
+    );
+    const expectedLines = ['foo', 'bar', 'baz', ''];
+    let callCount = 0;
+    rli.on('line', function(line) {
+      assert.strictEqual(line, expectedLines[callCount]);
+      callCount++;
+    });
+    rli.on('close', function() {
+      callCount++;
+    });
+    fi.emit('data', expectedLines.join('\n'));
+    fi.emit('end');
+    assert.strictEqual(callCount, expectedLines.length);
+    rli.close();
+  }
 
   // sending multiple newlines at once that does not end with a new line
   // and a `end` event(last line is)
 
   // \r\n should emit one line event, not two
-  fi = new FakeInput();
-  rli = new readline.Interface({ input: fi, output: fi, terminal: terminal });
-  expectedLines = ['foo', 'bar', 'baz', 'bat'];
-  callCount = 0;
-  rli.on('line', function(line) {
-    assert.strictEqual(line, expectedLines[callCount]);
-    callCount++;
-  });
-  fi.emit('data', expectedLines.join('\r\n'));
-  assert.strictEqual(callCount, expectedLines.length - 1);
-  rli.close();
+  {
+    const fi = new FakeInput();
+    const rli = new readline.Interface(
+      { input: fi, output: fi, terminal: terminal }
+    );
+    const expectedLines = ['foo', 'bar', 'baz', 'bat'];
+    let callCount = 0;
+    rli.on('line', function(line) {
+      assert.strictEqual(line, expectedLines[callCount]);
+      callCount++;
+    });
+    fi.emit('data', expectedLines.join('\r\n'));
+    assert.strictEqual(callCount, expectedLines.length - 1);
+    rli.close();
+  }
 
   // \r\n should emit one line event when split across multiple writes.
-  fi = new FakeInput();
-  rli = new readline.Interface({ input: fi, output: fi, terminal: terminal });
-  expectedLines = ['foo', 'bar', 'baz', 'bat'];
-  callCount = 0;
-  rli.on('line', function(line) {
-    assert.strictEqual(line, expectedLines[callCount]);
-    callCount++;
-  });
-  expectedLines.forEach(function(line) {
-    fi.emit('data', `${line}\r`);
-    fi.emit('data', '\n');
-  });
-  assert.strictEqual(callCount, expectedLines.length);
-  rli.close();
+  {
+    const fi = new FakeInput();
+    const rli = new readline.Interface(
+      { input: fi, output: fi, terminal: terminal }
+    );
+    const expectedLines = ['foo', 'bar', 'baz', 'bat'];
+    let callCount = 0;
+    rli.on('line', function(line) {
+      assert.strictEqual(line, expectedLines[callCount]);
+      callCount++;
+    });
+    expectedLines.forEach(function(line) {
+      fi.emit('data', `${line}\r`);
+      fi.emit('data', '\n');
+    });
+    assert.strictEqual(callCount, expectedLines.length);
+    rli.close();
+  }
 
   // \r should behave like \n when alone
-  fi = new FakeInput();
-  rli = new readline.Interface({ input: fi, output: fi, terminal: true });
-  expectedLines = ['foo', 'bar', 'baz', 'bat'];
-  callCount = 0;
-  rli.on('line', function(line) {
-    assert.strictEqual(line, expectedLines[callCount]);
-    callCount++;
-  });
-  fi.emit('data', expectedLines.join('\r'));
-  assert.strictEqual(callCount, expectedLines.length - 1);
-  rli.close();
+  {
+    const fi = new FakeInput();
+    const rli = new readline.Interface(
+      { input: fi, output: fi, terminal: true }
+    );
+    const expectedLines = ['foo', 'bar', 'baz', 'bat'];
+    let callCount = 0;
+    rli.on('line', function(line) {
+      assert.strictEqual(line, expectedLines[callCount]);
+      callCount++;
+    });
+    fi.emit('data', expectedLines.join('\r'));
+    assert.strictEqual(callCount, expectedLines.length - 1);
+    rli.close();
+  }
 
   // \r at start of input should output blank line
-  fi = new FakeInput();
-  rli = new readline.Interface({ input: fi, output: fi, terminal: true });
-  expectedLines = ['', 'foo' ];
-  callCount = 0;
-  rli.on('line', function(line) {
-    assert.strictEqual(line, expectedLines[callCount]);
-    callCount++;
-  });
-  fi.emit('data', '\rfoo\r');
-  assert.strictEqual(callCount, expectedLines.length);
-  rli.close();
+  {
+    const fi = new FakeInput();
+    const rli = new readline.Interface(
+      { input: fi, output: fi, terminal: true }
+    );
+    const expectedLines = ['', 'foo' ];
+    let callCount = 0;
+    rli.on('line', function(line) {
+      assert.strictEqual(line, expectedLines[callCount]);
+      callCount++;
+    });
+    fi.emit('data', '\rfoo\r');
+    assert.strictEqual(callCount, expectedLines.length);
+    rli.close();
+  }
 
   // Emit two line events when the delay
   // between \r and \n exceeds crlfDelay
@@ -331,185 +376,217 @@ function isWarned(emitter) {
 
   // \t when there is no completer function should behave like an ordinary
   // character
-  fi = new FakeInput();
-  rli = new readline.Interface({ input: fi, output: fi, terminal: true });
-  called = false;
-  rli.on('line', function(line) {
-    assert.strictEqual(line, '\t');
-    assert.strictEqual(called, false);
-    called = true;
-  });
-  fi.emit('data', '\t');
-  fi.emit('data', '\n');
-  assert.ok(called);
-  rli.close();
+  {
+    const fi = new FakeInput();
+    const rli = new readline.Interface(
+      { input: fi, output: fi, terminal: true }
+    );
+    let called = false;
+    rli.on('line', function(line) {
+      assert.strictEqual(line, '\t');
+      assert.strictEqual(called, false);
+      called = true;
+    });
+    fi.emit('data', '\t');
+    fi.emit('data', '\n');
+    assert.ok(called);
+    rli.close();
+  }
 
   // \t does not become part of the input when there is a completer function
-  fi = new FakeInput();
-  const completer = (line) => [[], line];
-  rli = new readline.Interface({
-    input: fi,
-    output: fi,
-    terminal: true,
-    completer: completer
-  });
-  called = false;
-  rli.on('line', function(line) {
-    assert.strictEqual(line, 'foo');
-    assert.strictEqual(called, false);
-    called = true;
-  });
-  for (const character of '\tfo\to\t') {
-    fi.emit('data', character);
+  {
+    const fi = new FakeInput();
+    const completer = (line) => [[], line];
+    const rli = new readline.Interface({
+      input: fi,
+      output: fi,
+      terminal: true,
+      completer: completer
+    });
+    let called = false;
+    rli.on('line', function(line) {
+      assert.strictEqual(line, 'foo');
+      assert.strictEqual(called, false);
+      called = true;
+    });
+    for (const character of '\tfo\to\t') {
+      fi.emit('data', character);
+    }
+    fi.emit('data', '\n');
+    assert.ok(called);
+    rli.close();
   }
-  fi.emit('data', '\n');
-  assert.ok(called);
-  rli.close();
 
   // constructor throws if completer is not a function or undefined
-  fi = new FakeInput();
-  assert.throws(function() {
-    readline.createInterface({
-      input: fi,
-      completer: 'string is not valid'
-    });
-  }, common.expectsError({
-    type: TypeError,
-    code: 'ERR_INVALID_OPT_VALUE'
-  }));
+  {
+    const fi = new FakeInput();
+    assert.throws(function() {
+      readline.createInterface({
+        input: fi,
+        completer: 'string is not valid'
+      });
+    }, common.expectsError({
+      type: TypeError,
+      code: 'ERR_INVALID_OPT_VALUE'
+    }));
+  }
 
   // duplicate lines are removed from history when
   // `options.removeHistoryDuplicates` is `true`
-  fi = new FakeInput();
-  rli = new readline.Interface({
-    input: fi,
-    output: fi,
-    terminal: true,
-    removeHistoryDuplicates: true
-  });
-  expectedLines = ['foo', 'bar', 'baz', 'bar', 'bat', 'bat'];
-  callCount = 0;
-  rli.on('line', function(line) {
-    assert.strictEqual(line, expectedLines[callCount]);
-    callCount++;
-  });
-  fi.emit('data', `${expectedLines.join('\n')}\n`);
-  assert.strictEqual(callCount, expectedLines.length);
-  fi.emit('keypress', '.', { name: 'up' }); // 'bat'
-  assert.strictEqual(rli.line, expectedLines[--callCount]);
-  fi.emit('keypress', '.', { name: 'up' }); // 'bar'
-  assert.notStrictEqual(rli.line, expectedLines[--callCount]);
-  assert.strictEqual(rli.line, expectedLines[--callCount]);
-  fi.emit('keypress', '.', { name: 'up' }); // 'baz'
-  assert.strictEqual(rli.line, expectedLines[--callCount]);
-  fi.emit('keypress', '.', { name: 'up' }); // 'foo'
-  assert.notStrictEqual(rli.line, expectedLines[--callCount]);
-  assert.strictEqual(rli.line, expectedLines[--callCount]);
-  assert.strictEqual(callCount, 0);
-  rli.close();
+  {
+    const fi = new FakeInput();
+    const rli = new readline.Interface({
+      input: fi,
+      output: fi,
+      terminal: true,
+      removeHistoryDuplicates: true
+    });
+    const expectedLines = ['foo', 'bar', 'baz', 'bar', 'bat', 'bat'];
+    let callCount = 0;
+    rli.on('line', function(line) {
+      assert.strictEqual(line, expectedLines[callCount]);
+      callCount++;
+    });
+    fi.emit('data', `${expectedLines.join('\n')}\n`);
+    assert.strictEqual(callCount, expectedLines.length);
+    fi.emit('keypress', '.', { name: 'up' }); // 'bat'
+    assert.strictEqual(rli.line, expectedLines[--callCount]);
+    fi.emit('keypress', '.', { name: 'up' }); // 'bar'
+    assert.notStrictEqual(rli.line, expectedLines[--callCount]);
+    assert.strictEqual(rli.line, expectedLines[--callCount]);
+    fi.emit('keypress', '.', { name: 'up' }); // 'baz'
+    assert.strictEqual(rli.line, expectedLines[--callCount]);
+    fi.emit('keypress', '.', { name: 'up' }); // 'foo'
+    assert.notStrictEqual(rli.line, expectedLines[--callCount]);
+    assert.strictEqual(rli.line, expectedLines[--callCount]);
+    assert.strictEqual(callCount, 0);
+    rli.close();
+  }
 
   // duplicate lines are not removed from history when
   // `options.removeHistoryDuplicates` is `false`
-  fi = new FakeInput();
-  rli = new readline.Interface({
-    input: fi,
-    output: fi,
-    terminal: true,
-    removeHistoryDuplicates: false
-  });
-  expectedLines = ['foo', 'bar', 'baz', 'bar', 'bat', 'bat'];
-  callCount = 0;
-  rli.on('line', function(line) {
-    assert.strictEqual(line, expectedLines[callCount]);
-    callCount++;
-  });
-  fi.emit('data', `${expectedLines.join('\n')}\n`);
-  assert.strictEqual(callCount, expectedLines.length);
-  fi.emit('keypress', '.', { name: 'up' }); // 'bat'
-  assert.strictEqual(rli.line, expectedLines[--callCount]);
-  fi.emit('keypress', '.', { name: 'up' }); // 'bar'
-  assert.notStrictEqual(rli.line, expectedLines[--callCount]);
-  assert.strictEqual(rli.line, expectedLines[--callCount]);
-  fi.emit('keypress', '.', { name: 'up' }); // 'baz'
-  assert.strictEqual(rli.line, expectedLines[--callCount]);
-  fi.emit('keypress', '.', { name: 'up' }); // 'bar'
-  assert.strictEqual(rli.line, expectedLines[--callCount]);
-  fi.emit('keypress', '.', { name: 'up' }); // 'foo'
-  assert.strictEqual(rli.line, expectedLines[--callCount]);
-  assert.strictEqual(callCount, 0);
-  rli.close();
+  {
+    const fi = new FakeInput();
+    const rli = new readline.Interface({
+      input: fi,
+      output: fi,
+      terminal: true,
+      removeHistoryDuplicates: false
+    });
+    const expectedLines = ['foo', 'bar', 'baz', 'bar', 'bat', 'bat'];
+    let callCount = 0;
+    rli.on('line', function(line) {
+      assert.strictEqual(line, expectedLines[callCount]);
+      callCount++;
+    });
+    fi.emit('data', `${expectedLines.join('\n')}\n`);
+    assert.strictEqual(callCount, expectedLines.length);
+    fi.emit('keypress', '.', { name: 'up' }); // 'bat'
+    assert.strictEqual(rli.line, expectedLines[--callCount]);
+    fi.emit('keypress', '.', { name: 'up' }); // 'bar'
+    assert.notStrictEqual(rli.line, expectedLines[--callCount]);
+    assert.strictEqual(rli.line, expectedLines[--callCount]);
+    fi.emit('keypress', '.', { name: 'up' }); // 'baz'
+    assert.strictEqual(rli.line, expectedLines[--callCount]);
+    fi.emit('keypress', '.', { name: 'up' }); // 'bar'
+    assert.strictEqual(rli.line, expectedLines[--callCount]);
+    fi.emit('keypress', '.', { name: 'up' }); // 'foo'
+    assert.strictEqual(rli.line, expectedLines[--callCount]);
+    assert.strictEqual(callCount, 0);
+    rli.close();
+  }
 
   // sending a multi-byte utf8 char over multiple writes
-  const buf = Buffer.from('☮', 'utf8');
-  fi = new FakeInput();
-  rli = new readline.Interface({ input: fi, output: fi, terminal: terminal });
-  callCount = 0;
-  rli.on('line', function(line) {
-    callCount++;
-    assert.strictEqual(line, buf.toString('utf8'));
-  });
-  [].forEach.call(buf, function(i) {
-    fi.emit('data', Buffer.from([i]));
-  });
-  assert.strictEqual(callCount, 0);
-  fi.emit('data', '\n');
-  assert.strictEqual(callCount, 1);
-  rli.close();
+  {
+    const buf = Buffer.from('☮', 'utf8');
+    const fi = new FakeInput();
+    const rli = new readline.Interface(
+      { input: fi, output: fi, terminal: terminal }
+    );
+    let callCount = 0;
+    rli.on('line', function(line) {
+      callCount++;
+      assert.strictEqual(line, buf.toString('utf8'));
+    });
+    [].forEach.call(buf, function(i) {
+      fi.emit('data', Buffer.from([i]));
+    });
+    assert.strictEqual(callCount, 0);
+    fi.emit('data', '\n');
+    assert.strictEqual(callCount, 1);
+    rli.close();
+  }
 
   // Regression test for repl freeze, #1968:
   // check that nothing fails if 'keypress' event throws.
-  fi = new FakeInput();
-  rli = new readline.Interface({ input: fi, output: fi, terminal: true });
-  const keys = [];
-  fi.on('keypress', function(key) {
-    keys.push(key);
-    if (key === 'X') {
-      throw new Error('bad thing happened');
-    }
-  });
-  try {
-    fi.emit('data', 'fooX');
-  } catch (e) { }
-  fi.emit('data', 'bar');
-  assert.strictEqual(keys.join(''), 'fooXbar');
-  rli.close();
+  {
+    const fi = new FakeInput();
+    const rli = new readline.Interface(
+      { input: fi, output: fi, terminal: true }
+    );
+    const keys = [];
+    fi.on('keypress', function(key) {
+      keys.push(key);
+      if (key === 'X') {
+        throw new Error('bad thing happened');
+      }
+    });
+    try {
+      fi.emit('data', 'fooX');
+    } catch (e) { }
+    fi.emit('data', 'bar');
+    assert.strictEqual(keys.join(''), 'fooXbar');
+    rli.close();
+  }
 
   // calling readline without `new`
-  fi = new FakeInput();
-  rli = readline.Interface({ input: fi, output: fi, terminal: terminal });
-  called = false;
-  rli.on('line', function(line) {
-    called = true;
-    assert.strictEqual(line, 'asdf');
-  });
-  fi.emit('data', 'asdf\n');
-  assert.ok(called);
-  rli.close();
+  {
+    const fi = new FakeInput();
+    const rli = readline.Interface(
+      { input: fi, output: fi, terminal: terminal }
+    );
+    let called = false;
+    rli.on('line', function(line) {
+      called = true;
+      assert.strictEqual(line, 'asdf');
+    });
+    fi.emit('data', 'asdf\n');
+    assert.ok(called);
+    rli.close();
+  }
 
   if (terminal) {
     // question
-    fi = new FakeInput();
-    rli = new readline.Interface({ input: fi, output: fi, terminal: terminal });
-    expectedLines = ['foo'];
-    rli.question(expectedLines[0], function() {
+    {
+      const fi = new FakeInput();
+      const rli = new readline.Interface(
+        { input: fi, output: fi, terminal: terminal }
+      );
+      const expectedLines = ['foo'];
+      rli.question(expectedLines[0], function() {
+        rli.close();
+      });
+      const cursorPos = rli._getCursorPos();
+      assert.strictEqual(cursorPos.rows, 0);
+      assert.strictEqual(cursorPos.cols, expectedLines[0].length);
       rli.close();
-    });
-    let cursorPos = rli._getCursorPos();
-    assert.strictEqual(cursorPos.rows, 0);
-    assert.strictEqual(cursorPos.cols, expectedLines[0].length);
-    rli.close();
+    }
 
     // sending a multi-line question
-    fi = new FakeInput();
-    rli = new readline.Interface({ input: fi, output: fi, terminal: terminal });
-    expectedLines = ['foo', 'bar'];
-    rli.question(expectedLines.join('\n'), function() {
+    {
+      const fi = new FakeInput();
+      const rli = new readline.Interface(
+        { input: fi, output: fi, terminal: terminal }
+      );
+      const expectedLines = ['foo', 'bar'];
+      rli.question(expectedLines.join('\n'), function() {
+        rli.close();
+      });
+      const cursorPos = rli._getCursorPos();
+      assert.strictEqual(cursorPos.rows, expectedLines.length - 1);
+      assert.strictEqual(cursorPos.cols, expectedLines.slice(-1)[0].length);
       rli.close();
-    });
-    cursorPos = rli._getCursorPos();
-    assert.strictEqual(cursorPos.rows, expectedLines.length - 1);
-    assert.strictEqual(cursorPos.cols, expectedLines.slice(-1)[0].length);
-    rli.close();
+    }
   }
 
   // isFullWidthCodePoint() should return false for non-numeric values
@@ -559,7 +636,10 @@ function isWarned(emitter) {
     .getStringWidth('\u001b[31m\u001b[39m'), 0);
   assert.strictEqual(internalReadline.getStringWidth('> '), 2);
 
-  assert.deepStrictEqual(fi.listeners(terminal ? 'keypress' : 'data'), []);
+  {
+    const fi = new FakeInput();
+    assert.deepStrictEqual(fi.listeners(terminal ? 'keypress' : 'data'), []);
+  }
 
   // check EventEmitter memory leak
   for (let i = 0; i < 12; i++) {
@@ -573,35 +653,39 @@ function isWarned(emitter) {
   }
 
   // can create a new readline Interface with a null output arugument
-  fi = new FakeInput();
-  rli = new readline.Interface({ input: fi, output: null, terminal: terminal });
+  {
+    const fi = new FakeInput();
+    const rli = new readline.Interface(
+      { input: fi, output: null, terminal: terminal }
+    );
 
-  called = false;
-  rli.on('line', function(line) {
-    called = true;
-    assert.strictEqual(line, 'asdf');
-  });
-  fi.emit('data', 'asdf\n');
-  assert.ok(called);
+    let called = false;
+    rli.on('line', function(line) {
+      called = true;
+      assert.strictEqual(line, 'asdf');
+    });
+    fi.emit('data', 'asdf\n');
+    assert.ok(called);
 
-  assert.doesNotThrow(function() {
-    rli.setPrompt('ddd> ');
-  });
+    assert.doesNotThrow(function() {
+      rli.setPrompt('ddd> ');
+    });
 
-  assert.doesNotThrow(function() {
-    rli.prompt();
-  });
+    assert.doesNotThrow(function() {
+      rli.prompt();
+    });
 
-  assert.doesNotThrow(function() {
-    rli.write('really shouldnt be seeing this');
-  });
+    assert.doesNotThrow(function() {
+      rli.write('really shouldnt be seeing this');
+    });
 
-  assert.doesNotThrow(function() {
-    rli.question('What do you think of node.js? ', function(answer) {
-      console.log('Thank you for your valuable feedback:', answer);
-      rli.close();
+    assert.doesNotThrow(function() {
+      rli.question('What do you think of node.js? ', function(answer) {
+        console.log('Thank you for your valuable feedback:', answer);
+        rli.close();
+      });
     });
-  });
+  }
 
   {
     const expected = terminal ?