introducing more tests

tests/frontend/specs/pageupdown.js

@@ -1,5 +1,4 @@
 'use strict';
-/*
 describe('Page Up/Down', function () {
   beforeEach(function (cb) {
     helper.newPad({
@@ -12,13 +11,13 @@ describe('Page Up/Down', function () {
           '\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n' +
           '\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n' +
           '\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n');
-        cb()
+        cb();
-      }
+      },
     });
   });
 
   // scrolls up 3 times
-  it('scrolls up on key stroke', async function(){
+  it('scrolls up on key stroke', async function () {
     let currentLineNumber = helper.caretLineNumber();
     helper.pageUp();
     await helper.waitForPromise(() => currentLineNumber > helper.caretLineNumber());
@@ -30,10 +29,10 @@ describe('Page Up/Down', function () {
     currentLineNumber = helper.caretLineNumber();
     helper.pageUp();
     await helper.waitForPromise(() => currentLineNumber > helper.caretLineNumber());
-  })
+  });
 
   // scrolls down 3 times
-  it('scrolls down on key stroke', async function(){
+  it('scrolls down on key stroke', async function () {
     // this places the caret in the first line
     await helper.edit('Line 1', 1);
 
@@ -48,10 +47,8 @@ describe('Page Up/Down', function () {
     currentLineNumber = helper.caretLineNumber();
     helper.pageDown();
     await helper.waitForPromise(() => currentLineNumber < helper.caretLineNumber());
-  })
+  });
-})
+});
-*/
-
 describe('Page Up/Down Beginning and End position', function () {
   beforeEach(function (cb) {
     helper.newPad({
@@ -87,28 +84,131 @@ describe('Page Up/Down Beginning and End position', function () {
     helper.pageUp();
     await helper.waitForPromise(() => currentLineNumber > helper.caretLineNumber());
 
-    // make sure caret is after hello
+    // make sure caret is at 0 position
     const pos = helper.padInner$.document.getSelection();
     await helper.waitForPromise(() => pos.anchorOffset === 0);
   });
+});
+describe('Line number integrity is kept between page up/down', function () {
+  beforeEach(function (cb) {
+    helper.newPad({
+      cb: async () => {
+        await helper.clearPad();
+        // 200 lines
+        await helper.edit(
+            '\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n' +
+          '\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n' +
+          '\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n' +
+          '\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n' +
+          '\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n');
+        cb();
+      },
+    });
+  });
 
-/*
+  const lineHistory = [];
-  // scrolls down 3 times
+
-  it('scrolls down on key stroke', async function () {
+  it('Page down three times to a given line, then page up and see if lines match', async function () {
     // this places the caret in the first line
     await helper.edit('Line 1', 1);
 
-    let currentLineNumber = helper.caretLineNumber();
+    const currentLineNumber = helper.caretLineNumber();
+    lineHistory.push(helper.caretLineNumber());
+
+    helper.pageDown();
+    await helper.waitForPromise(() => currentLineNumber < helper.caretLineNumber());
+    lineHistory.push(helper.caretLineNumber());
+
+    helper.pageDown();
+    await helper.waitForPromise(() => currentLineNumber < helper.caretLineNumber());
+    lineHistory.push(helper.caretLineNumber());
+
     helper.pageDown();
     await helper.waitForPromise(() => currentLineNumber < helper.caretLineNumber());
 
-    currentLineNumber = helper.caretLineNumber();
+    let futureLineNumber = helper.caretLineNumber();
-    helper.pageDown();
+    helper.pageUp();
-    await helper.waitForPromise(() => currentLineNumber < helper.caretLineNumber());
+    await helper.waitForPromise(() => futureLineNumber > helper.caretLineNumber());
+    if (helper.caretLineNumber() !== lineHistory[lineHistory.length]) {
+      throw new Error('Line History not being properly maintained');
+    }
+    lineHistory.pop();
 
-    currentLineNumber = helper.caretLineNumber();
+    futureLineNumber = helper.caretLineNumber();
-    helper.pageDown();
+    helper.pageUp();
-    await helper.waitForPromise(() => currentLineNumber < helper.caretLineNumber());
+    await helper.waitForPromise(() => futureLineNumber > helper.caretLineNumber());
+    if (helper.caretLineNumber() !== lineHistory[lineHistory.length]) {
+      throw new Error('Line History not being properly maintained');
+    }
+  });
+});
+describe('X character offset integrity is kept between page up/down', function () {
+  beforeEach(function (cb) {
+    helper.newPad({
+      cb: async () => {
+        await helper.clearPad();
+        // 200 lines
+        await helper.edit(
+            'hel\n\nhello\nhello\nhello\nhello\nhello\nhello\nhello\nhello\nhello\nhello\n' +
+            '\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n' +
+            '\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n' +
+            'hel\nhello\nhello\nhello\nhello\nhello\nhello\nhello\nhello\nhello\nhello\n' +
+            'hello\n\n\nhello\n\n\nhel\n\n\nhel\n\nhel\n\nhel\n\nhel\n\nhel\n\nhel\n\nhel');
+        cb();
+      },
+    });
+  });
+
+  it('Page down with an offset of 3 and check we keep our x offset', async function () {
+    /*
+       Consider this document..
+
+       hello*
+       world
+       .
+       .
+       .
+       BOO!
+
+       Hitting page down at the star point should put your caret after BOO!
+
+       Now consider that the empty lines are very long and the caret lands in them.
+       We respect the original x character offset and try to pass it forward.
+
+    */
+    // this places the caret in the first line
+    await helper.edit('xxx', 1); // caret is offset 6
+
+    let currentLineNumber = helper.caretLineNumber();
+    const nodeLength = helper.padInner$.document.getSelection().anchorNode.length;
+
+    const originalOffset = helper.padInner$.document.getSelection().anchorOffset;
+
+    helper.pageDown();
+    await helper.waitForPromise(() => currentLineNumber < helper.caretLineNumber());
+    await helper.waitForPromise(() => helper.padInner$.document.getSelection().anchorOffset === originalOffset ||
+      !helper.padInner$.document.getSelection().anchorNode.length);
+    // !helper.padInner$.document.getSelection().anchorNode.length) in the above line serves a useful purpose..
+    // We use it to ensure character offset is respected on empty lines but also to check that it's continued
+    // to be respected on next page downs.
+
+    helper.pageDown();
+    await helper.waitForPromise(() => currentLineNumber < helper.caretLineNumber());
+    console.log(helper.padInner$.document.getSelection().anchorNode.length, 'WAT');
+    await helper.waitForPromise(() => helper.padInner$.document.getSelection().anchorOffset === originalOffset ||
+      !helper.padInner$.document.getSelection().anchorNode.length);
+
+    helper.pageDown();
+    await helper.waitForPromise(() => currentLineNumber < helper.caretLineNumber());
+    await helper.waitForPromise(() => helper.padInner$.document.getSelection().anchorOffset === originalOffset ||
+      !helper.padInner$.document.getSelection().anchorNode.length);
+
+    // need to reset for page up
+    currentLineNumber = helper.caretLineNumber();
+
+    helper.pageUp();
+    await helper.waitForPromise(() => currentLineNumber > helper.caretLineNumber());
+    await helper.waitForPromise(() => helper.padInner$.document.getSelection().anchorOffset === originalOffset ||
+      !helper.padInner$.document.getSelection().anchorNode.length);
   });
-  */
 });