test: expand test coverage of readline

PR-URL: https://github.com/nodejs/node/pull/12755
Reviewed-By: Anna Henningsen <anna@addaleax.net>

test/parallel/test-readline-csi.js

@@ -0,0 +1,90 @@
+// Flags: --expose-internals
+'use strict';
+
+const common = require('../common');
+const assert = require('assert');
+const readline = require('readline');
+const { Writable } = require('stream');
+const { CSI } = require('internal/readline');
+
+{
+  assert(CSI);
+  assert.strictEqual(CSI.kClearToBeginning, '\x1b[1K');
+  assert.strictEqual(CSI.kClearToEnd, '\x1b[0K');
+  assert.strictEqual(CSI.kClearLine, '\x1b[2K');
+  assert.strictEqual(CSI.kClearScreenDown, '\x1b[0J');
+  assert.strictEqual(CSI`1${2}3`, '\x1b[123');
+}
+
+class TestWritable extends Writable {
+  constructor() {
+    super();
+    this.data = '';
+  }
+  _write(chunk, encoding, callback) {
+    this.data += chunk.toString();
+    callback();
+  }
+}
+
+const writable = new TestWritable();
+
+readline.clearScreenDown(writable);
+assert.deepStrictEqual(writable.data, CSI.kClearScreenDown);
+
+writable.data = '';
+readline.clearLine(writable, -1);
+assert.deepStrictEqual(writable.data, CSI.kClearToBeginning);
+
+writable.data = '';
+readline.clearLine(writable, 1);
+assert.deepStrictEqual(writable.data, CSI.kClearToEnd);
+
+writable.data = '';
+readline.clearLine(writable, 0);
+assert.deepStrictEqual(writable.data, CSI.kClearLine);
+
+// Nothing is written when moveCursor 0, 0
+[
+  [0, 0, ''],
+  [1, 0, '\x1b[1C'],
+  [-1, 0, '\x1b[1D'],
+  [0, 1, '\x1b[1B'],
+  [0, -1, '\x1b[1A'],
+  [1, 1, '\x1b[1C\x1b[1B'],
+  [-1, 1, '\x1b[1D\x1b[1B'],
+  [-1, -1, '\x1b[1D\x1b[1A'],
+  [1, -1, '\x1b[1C\x1b[1A'],
+].forEach((set) => {
+  writable.data = '';
+  readline.moveCursor(writable, set[0], set[1]);
+  assert.deepStrictEqual(writable.data, set[2]);
+});
+
+assert.doesNotThrow(() => readline.cursorTo(null));
+assert.doesNotThrow(() => readline.cursorTo());
+
+writable.data = '';
+assert.doesNotThrow(() => readline.cursorTo(writable, 'a'));
+assert.strictEqual(writable.data, '');
+
+writable.data = '';
+assert.doesNotThrow(() => readline.cursorTo(writable, 'a', 'b'));
+assert.strictEqual(writable.data, '');
+
+writable.data = '';
+assert.throws(
+  () => readline.cursorTo(writable, 'a', 1),
+  common.expectsError({
+    type: Error,
+    message: /^Can't set cursor row without also setting it's column$/
+  }));
+assert.strictEqual(writable.data, '');
+
+writable.data = '';
+assert.doesNotThrow(() => readline.cursorTo(writable, 1, 'a'));
+assert.strictEqual(writable.data, '\x1b[2G');
+
+writable.data = '';
+assert.doesNotThrow(() => readline.cursorTo(writable, 1, 2));
+assert.strictEqual(writable.data, '\x1b[3;2H');