Initial landing of Screen, Terminal, and VT100 classes.

chrome/browser/resources/hterm/js/vt100_tests.js

+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+/**
+ * @fileoverview VT100 test suite.
+ *
+ * This is more of an integration test suite for the VT100 and Terminal classes,
+ * as each test typically sends strings into the VT100 parser and then reads
+ * the terminal to verify that everyone did the right thing.
+ */
+
+hterm.VT100.Tests = new TestManager.Suite('hterm.VT100.Tests');
+
+hterm.VT100.Tests.prototype.setup = function(cx) {
+  this.setDefaults(cx,
+      { visibleColumnCount: 15,
+        visibleRowCount: 6,
+        fontSize: 15,
+        lineHeight: 17,
+        charWidth: 9,
+        scrollbarWidth: 16,
+      });
+};
+
+/**
+ * Clear out the current document and create a new hterm.Terminal object for
+ * testing.
+ *
+ * Called before each test case in this suite.
+ */
+hterm.VT100.Tests.prototype.preamble = function(result, cx) {
+  var document = cx.window.document;
+
+  document.body.innerHTML = '';
+
+  var div = document.createElement('div');
+  div.style.position = 'absolute';
+  div.style.height = this.lineHeight * this.visibleRowCount + 'px';
+  div.style.width = this.charWidth * this.visibleColumnCount +
+      this.scrollbarWidth + 'px';
+  document.body.appendChild(div);
+
+  cx.window.terminal = this.terminal = new hterm.Terminal(
+      this.fontSize, this.lineHeight);
+
+  this.terminal.decorate(div);
+};
+
+/**
+ * Ensure that blink is off after the test so we don't have runaway timeouts.
+ *
+ * Called after each test case in this suite.
+ */
+hterm.VT100.Tests.prototype.postamble = function(result, cx) {
+  this.terminal.setCursorBlink(false);
+};
+
+/**
+ * Overridden addTest method.
+ *
+ * Every test in this suite needs to wait for the terminal initialization to
+ * complete asynchronously.  Rather than stick a bunch of biolerplate into each
+ * test case, we use this overridden addText method to add a proxy around the
+ * actual test.
+ */
+hterm.VT100.Tests.addTest = function(name, callback) {
+  function testProxy(result, cx) {
+    setTimeout(function() {
+        this.terminal.setCursorPosition(0, 0);
+        this.terminal.setCursorVisible(true);
+        callback.apply(this, [result, cx]);
+      }, 0);
+
+    result.requestTime(200);
+  }
+
+  TestManager.Suite.addTest.apply(this, [name, testProxy]);
+};
+
+/**
+ * Basic sanity test to make sure that when we insert plain text it appears
+ * on the screen and scrolls into the scrollback buffer correctly.
+ */
+hterm.VT100.Tests.addTest('sanity', function(result, cx) {
+    this.terminal.interpret('0\n1\n2\n3\n4\n5\n6\n7\n8\n9\n10\n11\n12');
+
+    var text = this.terminal.getRowsText(0, 13);
+    result.assertEQ(text, '0\n1\n2\n3\n4\n5\n6\n7\n8\n9\n10\n11\n12');
+
+    result.assertEQ(this.terminal.scrollbackRows_.length, 7);
+
+    result.pass();
+  });
+
+/**
+ * Basic cursor positioning tests.
+ *
+ * TODO(rginda): Test the VT52 variants too.
+ */
+hterm.VT100.Tests.addTest('cursor-relative', function(result, cx) {
+    this.terminal.interpret('line 1\nline 2\nline 3');
+    this.terminal.interpret('\x1b[A\x1b[Dtwo' +
+                            '\x1b[3D' +
+                            '\x1b[Aone' +
+                            '\x1b[4D' +
+                            '\x1b[2B' +
+                            '\x1b[Cthree');
+    var text = this.terminal.getRowsText(0, 3);
+    result.assertEQ(text, 'line one\nline two\nline three');
+    result.pass();
+  });
+
+/**
+ * Test absolute cursor positioning.
+ */
+hterm.VT100.Tests.addTest('cursor-absolute', function(result, cx) {
+    this.terminal.interpret('line 1\nline 2\nline 3');
+
+    this.terminal.interpret('\x1b[1Gline three' +
+                            '\x1b[2;6Htwo' +
+                            '\x1b[1;5f one');
+
+    var text = this.terminal.getRowsText(0, 3);
+    result.assertEQ(text, 'line one\nline two\nline three');
+
+    result.pass();
+  });
+
+/**
+ * Test line positioning.
+ */
+hterm.VT100.Tests.addTest('line-position', function(result, cx) {
+    this.terminal.interpret('line 1\nline 2\nline 3');
+
+    this.terminal.interpret('\x1b[Fline two' +
+                            '\x1b[Fline one' +
+                            '\x1b[E\x1b[Eline three');
+
+    var text = this.terminal.getRowsText(0, 3);
+    result.assertEQ(text, 'line one\nline two\nline three');
+    result.pass();
+  });
+
+/**
+ * Test that a partial sequence is buffered until the entire sequence is
+ * received.
+ */
+hterm.VT100.Tests.addTest('partial-sequence', function(result, cx) {
+    this.terminal.interpret('line 1\nline 2\nline three');
+
+    this.terminal.interpret('\x1b');
+    this.terminal.interpret('[');
+    this.terminal.interpret('5');
+    this.terminal.interpret('D');
+    this.terminal.interpret('\x1b[');
+    this.terminal.interpret('Atwo\x1b[3');
+    this.terminal.interpret('D\x1b[Aone');
+
+    var text = this.terminal.getRowsText(0, 3);
+    result.assertEQ(text, 'line one\nline two\nline three');
+    result.pass();
+  });
+
+/**
+ * Test that two ESC characters in a row are handled properly.
+ */
+hterm.VT100.Tests.addTest('double-sequence', function(result, cx) {
+    this.terminal.interpret('line one\nline two\nline 3');
+
+    this.terminal.interpret('\x1b[\x1b[Dthree');
+
+    var text = this.terminal.getRowsText(0, 3);
+    result.assertEQ(text, 'line one\nline two\nline three');
+    result.pass();
+  });
+
+/**
+ * Test the erase left command.
+ */
+hterm.VT100.Tests.addTest('erase-left', function(result, cx) {
+    this.terminal.interpret('line one\noooooooo\nline three');
+    this.terminal.interpret('\x1b[5D\x1b[A' +
+                            '\x1b[1Ktw');
+
+    var text = this.terminal.getRowsText(0, 3);
+    result.assertEQ(text,
+                    'line one\n' +
+                    '     two\n' +
+                    'line three');
+    result.pass();
+  });
+
+/**
+ * Test the erase right command.
+ */
+hterm.VT100.Tests.addTest('erase-right', function(result, cx) {
+    this.terminal.interpret('line one\nline XXXX\nline three');
+    this.terminal.interpret('\x1b[5D\x1b[A' +
+                            '\x1b[0Ktwo');
+
+    var text = this.terminal.getRowsText(0, 3);
+    result.assertEQ(text,
+                    'line one\n' +
+                    'line two\n' +
+                    'line three');
+    result.pass();
+  });
+
+/**
+ * Test the erase line command.
+ */
+hterm.VT100.Tests.addTest('erase-line', function(result, cx) {
+    this.terminal.interpret('line one\nline twoo\nline three');
+    this.terminal.interpret('\x1b[5D\x1b[A' +
+                            '\x1b[2Ktwo');
+
+    var text = this.terminal.getRowsText(0, 3);
+    result.assertEQ(text,
+                    'line one\n' +
+                    '     two\n' +
+                    'line three');
+    result.pass();
+  });
+
+/**
+ * Test the erase above command.
+ */
+hterm.VT100.Tests.addTest('erase-above', function(result, cx) {
+    this.terminal.interpret('line one\noooooooo\nline three');
+    this.terminal.interpret('\x1b[5D\x1b[A' +
+                            '\x1b[1Jtw');
+
+    var text = this.terminal.getRowsText(0, 3);
+    result.assertEQ(text,
+                    '\n' +
+                    '     two\n' +
+                    'line three');
+    result.pass();
+  });
+
+/**
+ * Test the erase all command.
+ */
+hterm.VT100.Tests.addTest('erase-all', function(result, cx) {
+    this.terminal.interpret('line one\nline XXXX\nline three');
+    this.terminal.interpret('\x1b[5D\x1b[A' +
+                            '\x1b[2Jtwo');
+
+    var text = this.terminal.getRowsText(0, 3);
+    result.assertEQ(text,
+                    '\n' +
+                    '     two\n' +
+                    '');
+    result.pass();
+  });
+
+/**
+ * Test the erase below command.
+ */
+hterm.VT100.Tests.addTest('erase-below', function(result, cx) {
+    this.terminal.interpret('line one\nline XXXX\nline three');
+    this.terminal.interpret('\x1b[5D\x1b[A' +
+                            '\x1b[0Jtwo');
+
+    var text = this.terminal.getRowsText(0, 3);
+    result.assertEQ(text,
+                    'line one\n' +
+                    'line two\n' +
+                    '');
+    result.pass();
+  });
+
+/**
+ * Test the erase character command.
+ */
+hterm.VT100.Tests.addTest('erase-char', function(result, cx) {
+    this.terminal.interpret('line one\nline XXXX\nline three');
+    this.terminal.interpret('\x1b[5D\x1b[A' +
+                            '\x1b[4Xtwo');
+
+    var text = this.terminal.getRowsText(0, 3);
+    result.assertEQ(text,
+                    'line one\n' +
+                    'line two\n' +
+                    'line three');
+    result.pass();
+  });
+
+/**
+ * Test the insert line command.
+ */
+hterm.VT100.Tests.addTest('insert-line', function(result, cx) {
+    this.terminal.interpret('line two\nline three');
+    this.terminal.interpret('\x1b[5D\x1b[2A\x1b[L' +
+                            'line one');
+
+    var text = this.terminal.getRowsText(0, 3);
+    result.assertEQ(text,
+                    'line one\n' +
+                    'line two\n' +
+                    'line three');
+    result.pass();
+  });
+
+/**
+ * Test the insert line command with an argument.
+ */
+hterm.VT100.Tests.addTest('insert-lines', function(result, cx) {
+    this.terminal.interpret('line three\n\n');
+    this.terminal.interpret('\x1b[5D\x1b[2A\x1b[2L' +
+                            'line one\nline two');
+
+    var text = this.terminal.getRowsText(0, 3);
+    result.assertEQ(text,
+                    'line one\n' +
+                    'line two\n' +
+                    'line three');
+    result.pass();
+  });
+
+/**
+ * Test that the insert line command handles overflow properly.
+ */
+hterm.VT100.Tests.addTest('insert-toomany-lines', function(result, cx) {
+    this.terminal.interpret('XXXXX');
+    this.terminal.interpret('\x1b[6L' +
+                            'line one\nline two\nline three');
+
+    var text = this.terminal.getRowsText(0, 5);
+    result.assertEQ(text,
+                    'line one\n' +
+                    'line two\n' +
+                    'line three\n' +
+                    '\n' +
+                    '');
+    result.pass();
+  });
+
+/**
+ * Test the delete line command.
+ */
+hterm.VT100.Tests.addTest('delete-line', function(result, cx) {
+    this.terminal.interpret('line one\nline two\n' +
+                            'XXXXXXXX\n' +
+                            'line XXXXX');
+    this.terminal.interpret('\x1b[5D\x1b[A\x1b[Mthree');
+
+    var text = this.terminal.getRowsText(0, 3);
+    result.assertEQ(text,
+                    'line one\n' +
+                    'line two\n' +
+                    'line three');
+    result.pass();
+  });
+
+/**
+ * Test the delete line command with an argument.
+ */
+hterm.VT100.Tests.addTest('delete-lines', function(result, cx) {
+    this.terminal.interpret('line one\nline two\n' +
+                            'XXXXXXXX\nXXXXXXXX\n' +
+                            'line XXXXX');
+    this.terminal.interpret('\x1b[5D\x1b[2A\x1b[2Mthree');
+
+    var text = this.terminal.getRowsText(0, 3);
+    result.assertEQ(text,
+                    'line one\n' +
+                    'line two\n' +
+                    'line three');
+    result.pass();
+  });
+
+/**
+ * Test the insert space command.
+ */
+hterm.VT100.Tests.addTest('insert-space', function(result, cx) {
+    this.terminal.interpret('line one\nlinetwo\nline three');
+    this.terminal.interpret('\x1b[6D\x1b[A\x1b[@');
+
+    var text = this.terminal.getRowsText(0, 3);
+    result.assertEQ(text,
+                    'line one\n' +
+                    'line two\n' +
+                    'line three');
+    result.pass();
+  });
+
+/**
+ * Test the insert space command with an argument.
+ */
+hterm.VT100.Tests.addTest('insert-spaces', function(result, cx) {
+    this.terminal.interpret('line one\nlinetwo\nline three');
+    this.terminal.interpret('\x1b[6D\x1b[A\x1b[3@');
+
+    var text = this.terminal.getRowsText(0, 3);
+    result.assertEQ(text,
+                    'line one\n' +
+                    'line   two\n' +
+                    'line three');
+    result.pass();
+  });
+
+/**
+ * Test the delete characters command.
+ */
+hterm.VT100.Tests.addTest('delete-chars', function(result, cx) {
+    this.terminal.interpret('line one\nline XXXX\nline three');
+    this.terminal.interpret('\x1b[5D\x1b[A\x1b[4Ptwo');
+
+    var text = this.terminal.getRowsText(0, 3);
+    result.assertEQ(text,
+                    'line one\n' +
+                    'line two\n' +
+                    'line three');
+    result.pass();
+  });
+
+/**
+ * Test that the delete characters command handles overflow properly.
+ */
+hterm.VT100.Tests.addTest('delete-toomany', function(result, cx) {
+    this.terminal.interpret('line one\nline XXXX\nline three');
+    this.terminal.interpret('\x1b[5D\x1b[A\x1b[20Ptwo');
+
+    var text = this.terminal.getRowsText(0, 3);
+    result.assertEQ(text,
+                    'line one\n' +
+                    'line two\n' +
+                    'line three');
+    result.pass();
+  });
+
+/**
+ * Test the scroll up command.
+ */
+hterm.VT100.Tests.addTest('scroll-up', function(result, cx) {
+    this.terminal.interpret('\n\nline one\nline two\nline XXXXX');
+    this.terminal.interpret('\x1b[5D\x1b[2A\x1b[2Sthree');
+
+    var text = this.terminal.getRowsText(0, 3);
+    result.assertEQ(text,
+                    'line one\n' +
+                    'line two\n' +
+                    'line three');
+    result.pass();
+  });
+
+/**
+ * Test the scroll down command.
+ */
+hterm.VT100.Tests.addTest('scroll-down', function(result, cx) {
+    this.terminal.interpret('line one\nline two\nline XXXXX\n');
+    this.terminal.interpret('     \x1b[Tthree');
+
+    var text = this.terminal.getRowsText(0, 5);
+    result.assertEQ(text,
+                    '\n' +
+                    'line one\n' +
+                    'line two\n' +
+                    'line three\n' +
+                    '     ');
+    result.pass();
+  });
+
+/**
+ * Test the absolute line positioning command.
+ */
+hterm.VT100.Tests.addTest('line-position-absolute', function(result, cx) {
+    this.terminal.interpret('line XXX\nline YYY\nline ZZZZZ\n');
+    this.terminal.interpret('     \x1b[3dthree\x1b[5D');
+    this.terminal.interpret('\x1b[2dtwo\x1b[3D');
+    this.terminal.interpret('\x1b[1done');
+
+    var text = this.terminal.getRowsText(0, 3);
+    result.assertEQ(text,
+                    'line one\n' +
+                    'line two\n' +
+                    'line three');
+    result.pass();
+  });
+
+/**
+ * Test the device attributes command.
+ */
+hterm.VT100.Tests.addTest('device-attributes', function(result, cx) {
+    this.terminal.interpret('\x1b[c');
+    result.assertEQ(this.terminal.vt100_.getAndClearPendingResponse(),
+                    '\x1b[?1;2c');
+    result.pass();
+  });
+
+/**
+ * TODO(rginda): Test the clear tabstops on this line command.
+ */
+hterm.VT100.Tests.disableTest('clear-line-tabstops', function(result, cx) {
+    '[0g';
+  });
+
+/**
+ * TODO(rginda): Test the clear all tabstops command.
+ */
+hterm.VT100.Tests.disableTest('clear-all-tabstops', function(result, cx) {
+    '[3g';
+  });
+
+/**
+ * TODO(rginda): Test text attributes.
+ */
+hterm.VT100.Tests.disableTest('color-change', function(result, cx) {
+    '[Xm';
+  });
+
+/**
+ * Test the status report command.
+ */
+hterm.VT100.Tests.addTest('status-report', function(result, cx) {
+    this.terminal.interpret('\x1b[5n');
+    result.assertEQ(this.terminal.vt100_.getAndClearPendingResponse(),
+                    '\x1b0n');
+
+    this.terminal.interpret('line one\nline two\nline three');
+    // Reposition the cursor and ask for a position report.
+    this.terminal.interpret('\x1b[5D\x1b[A\x1b[6n');
+    result.assertEQ(this.terminal.vt100_.getAndClearPendingResponse(),
+                    '\x1b[2;6R');
+
+    var text = this.terminal.getRowsText(0, 3);
+    result.assertEQ(text,
+                    'line one\n' +
+                    'line two\n' +
+                    'line three');
+
+    result.pass();
+  });
+
+/**
+ * Test that various mode commands correctly change the state of the terminal.
+ *
+ * Most of these should have more in-depth testing below.
+ */
+hterm.VT100.Tests.addTest('mode-bits', function(result, cx) {
+    this.terminal.interpret('\x1b[?1h');
+    result.assertEQ(this.terminal.vt100_.getApplicationCursor(), true);
+
+    this.terminal.interpret('\x1b[?1l');
+    result.assertEQ(this.terminal.vt100_.getApplicationCursor(), false);
+
+    var fg = this.terminal.foregroundColor;
+    var bg = this.terminal.backgroundColor;
+
+    this.terminal.interpret('\x1b[?5h');
+    result.assertEQ(this.terminal.scrollPort_.getForegroundColor(), bg);
+    result.assertEQ(this.terminal.scrollPort_.getBackgroundColor(), fg);
+
+    this.terminal.interpret('\x1b[?5l');
+    result.assertEQ(this.terminal.scrollPort_.getForegroundColor(), fg);
+    result.assertEQ(this.terminal.scrollPort_.getBackgroundColor(), bg);
+
+    this.terminal.interpret('\x1b[?5l');
+    result.assertEQ(this.terminal.scrollPort_.getForegroundColor(), fg);
+    result.assertEQ(this.terminal.scrollPort_.getBackgroundColor(), bg);
+
+    this.terminal.interpret('\x1b[?6h');
+    result.assertEQ(this.terminal.options_.originMode, true);
+
+    this.terminal.interpret('\x1b[?6l');
+    result.assertEQ(this.terminal.options_.originMode, false);
+
+    this.terminal.interpret('\x1b[4h');
+    result.assertEQ(this.terminal.options_.insertMode, true);
+
+    this.terminal.interpret('\x1b[4l');
+    result.assertEQ(this.terminal.options_.insertMode, false);
+
+    this.terminal.interpret('\x1b[?7h');
+    result.assertEQ(this.terminal.options_.wraparound, true);
+
+    this.terminal.interpret('\x1b[?7l');
+    result.assertEQ(this.terminal.options_.wraparound, false);
+
+    this.terminal.interpret('\x1b[?12l');
+    result.assertEQ(this.terminal.options_.cursorBlink, false);
+    result.assertEQ(this.terminal.cursorTimer_, null);
+
+    this.terminal.interpret('\x1b[?12h');
+    result.assertEQ(this.terminal.options_.cursorBlink, true);
+    result.assert(this.terminal.cursorTimer_ != null);
+
+    this.terminal.interpret('\x1b[?25l');
+    result.assertEQ(this.terminal.options_.cursorVisible, false);
+    result.assertEQ(this.terminal.cursorNode_.style.display, 'none');
+
+    this.terminal.interpret('\x1b[?25h');
+    result.assertEQ(this.terminal.options_.cursorVisible, true);
+
+    // Turn off blink so we know the cursor should be on.
+    this.terminal.interpret('\x1b[?12l');
+    result.assertEQ(this.terminal.cursorNode_.style.display, 'block');
+
+    this.terminal.interpret('\x1b[?45h');
+    result.assertEQ(this.terminal.options_.reverseWraparound, true);
+
+    this.terminal.interpret('\x1b[?45l');
+    result.assertEQ(this.terminal.options_.reverseWraparound, false);
+
+    this.terminal.interpret('\x1b[?67h');
+    result.assertEQ(this.terminal.vt100_.backspaceSendsBackspace_, true);
+
+    this.terminal.interpret('\x1b[?67l');
+    result.assertEQ(this.terminal.vt100_.backspaceSendsBackspace_, false);
+
+    this.terminal.interpret('\x1b[?1036h');
+    result.assertEQ(this.terminal.vt100_.metaSendsEscape_, true);
+
+    this.terminal.interpret('\x1b[?1036l');
+    result.assertEQ(this.terminal.vt100_.metaSendsEscape_, false);
+
+    this.terminal.interpret('\x1b[?1039h');
+    result.assertEQ(this.terminal.vt100_.altSendsEscape_, true);
+
+    this.terminal.interpret('\x1b[?1039l');
+    result.assertEQ(this.terminal.vt100_.altSendsEscape_, false);
+
+    result.assertEQ(this.terminal.screen_,
+                    this.terminal.primaryScreen_);
+
+    this.terminal.interpret('\x1b[?1049h');
+    result.assertEQ(this.terminal.screen_,
+                    this.terminal.alternateScreen_);
+
+    this.terminal.interpret('\x1b[?1049l');
+    result.assertEQ(this.terminal.screen_,
+                    this.terminal.primaryScreen_);
+
+    result.pass();
+  });
+
+/**
+ * TODO(rginda): Test origin mode.
+ */
+hterm.VT100.Tests.disableTest('origin-mode', function(result, cx) {
+  });
+
+/**
+ * Test insert/overwrite mode.
+ */
+hterm.VT100.Tests.addTest('insert-mode', function(result, cx) {
+    // Should be off by default.
+    result.assertEQ(this.terminal.options_.insertMode, false);
+
+    this.terminal.interpret('\x1b[4h');
+    this.terminal.interpret(' one\x1b[4Dline\n');
+
+    this.terminal.interpret('\x1b[4l');
+    this.terminal.interpret('XXXXXXXX\x1b[8Dline two\n');
+
+    this.terminal.interpret('\x1b[4h');
+    this.terminal.interpret(' three\x1b[6Dline');
+
+    var text = this.terminal.getRowsText(0, 3);
+    result.assertEQ(text,
+                    'line one\n' +
+                    'line two\n' +
+                    'line three');
+
+    result.pass();
+  });
+
+/**
+ * Test wraparound mode.
+ */
+hterm.VT100.Tests.addTest('wraparound-mode', function(result, cx) {
+    // Should be on by default.
+    result.assertEQ(this.terminal.options_.wraparound, true);
+
+    this.terminal.interpret('-----  1  -----');
+    this.terminal.interpret('-----  2  -----');
+
+    var text = this.terminal.getRowsText(0, 3);
+    result.assertEQ(text,
+                    '-----  1  -----\n' +
+                    '-----  2  -----\n' +
+                    '');
+
+
+    result.pass();
+  });
+
+/**
+ * Test the interactions between insert and wraparound modes.
+ */
+hterm.VT100.Tests.addTest('insert-wrap', function(result, cx) {
+    // Should be on by default.
+    result.assertEQ(this.terminal.options_.wraparound, true);
+
+    this.terminal.interpret('' + // Insert off, wrap on (default).
+                            'AAAAXX\n' +
+                            '[?7l' +  // Insert on, wrap off.
+                            'AAAAXX\n' +
+                            '[?7h' +  // Insert on, wrap on.
+                            'AAAAXX\n' +
+                            '[?7l' +  // Insert off, wrap off.
+                            'AAAAXX');
+
+    var text = this.terminal.getRowsText(0, 6);
+    result.assertEQ(text,
+                    '              A\n' +
+                    'XXA\n' +
+
+                    'XX             \n' +
+
+                    '              A\n' +
+                    'XXAAA\n' +
+
+                    'XX            A');
+
+
+    result.pass();
+  });
+
+hterm.VT100.Tests.addTest('alternate-screen', function(result, cx) {
+    this.terminal.interpret('1\n2\n3\n4\n5\n6\n7\n8\n9\n10');
+    this.terminal.interpret('\x1b[3;3f');  // Leave the cursor at (3,3)
+    var text = this.terminal.getRowsText(0, 10);
+    result.assertEQ(text, '1\n2\n3\n4\n5\n6\n7\n8\n9\n10');
+
+    // Switch to alternate screen.
+    this.terminal.interpret('\x1b[?1049h');
+    text = this.terminal.getRowsText(0, 10);
+    result.assertEQ(text, '1\n2\n3\n4\n\n\n\n\n\n');
+
+    this.terminal.interpret('\nhi');
+    text = this.terminal.getRowsText(0, 10);
+    result.assertEQ(text, '1\n2\n3\n4\n\nhi\n\n\n\n');
+
+    // Switch back to primary screen.
+    this.terminal.interpret('\x1b[?1049l');
+    text = this.terminal.getRowsText(0, 10);
+    result.assertEQ(text, '1\n2\n3\n4\n5\n6\n7\n8\n9\n10');
+
+    this.terminal.interpret('XX');
+    text = this.terminal.getRowsText(0, 10);
+    result.assertEQ(text, '1\n2\n3\n4\n5\n6\n7 XX\n8\n9\n10');
+
+    // Aand back to alternate screen.
+    this.terminal.interpret('\x1b[?1049h');
+    text = this.terminal.getRowsText(0, 10);
+    result.assertEQ(text, '1\n2\n3\n4\n\nhi\n\n\n\n');
+
+    this.terminal.interpret('XX');
+    text = this.terminal.getRowsText(0, 10);
+    result.assertEQ(text, '1\n2\n3\n4\n\nhiXX\n\n\n\n');
+
+    result.pass();
+  });