Add missing formatting information in MS Excel cells (strikethrough, superscript/subscript)

[CyrilleB79]

Link to issue number:

None

Summary of the issue:

Some formatting information is not reported when navigating from one cell to another in Excel, although the corresponding category is checked in Document formatting settings.

• strikethrough is not reported even if font attributes is checked
• superscript or subscript is not reported even if the corresponding option is checked

Description of how this pull request fixes the issue:

• Added the missing code to handle strikethrough, superscript and subscript in _getFormatFieldAndOffsets
• In reportFocus, speak the format field sequence not only if the current cell has format field info to speak but also if the previous cell has it. This is done to report 'baseline' when transitioning from a cell with superscript to a cell without formatting since 'baseline', being the default, is not stored in the cell's format fields.

Note

This PR allows to have strikethrough and superscript/subscript reported if the whole cell is formatted with these attributes.
If having a whole cell formatted as superscript or subscript is probably not a real-life use case, strikethrough may be quite common.

Testing strategy:

Manual test:

1. Created an Excel sheet with some cells with various formatting: strikethrough, underline, bold, superscript, subscript. No cell has mixed formatting, i.e. formatting applied to only some characters of the text of a cell.
2. Set NVDA to report font attributes and not superscript/subscript.
3. Moved the active cell with arrows to perform each possible transition on the sheet.
4. Re-test step 3 with the following options:
   • font attributes OFF / superscript and subscript ON
   • font attributes OFF / superscript and subscript OFF
   • font attributes ON / superscript and subscript ON

No specific unit or system test for this PR.

Known issues with pull request:

This PR does not address the following points that are still issues with NVDA:

• Reporting mixed formatting in the same cell when moving cell by cell, e.g. a cell having text with only one character in exponent and not the rest (Excel text formatting information inconsistently read #6478 and partly Reporting formatting on a cell with multiple colours fails in Excel 2013 #7277).
• Reporting any formatting when moving in the text inside a cell (No formatting information in edit mode in Excel #6479).
• Report strikethrough, superscript and subscript at cell level when UIA for Excel advanced option is enabled. Indeed, in this case, the other formatting info (bold, italic, etc.) are not reported either.

Change log entry:

Section: Bug fixes
Strikethrough, superscript and subscript are now reported when navigating through Excel cells if the corresponding option is enabled (#12264)

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• Unit tests.
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[AppVeyorBot]

• System test failure
• Build (for testing PR)

See test results for failed build of commit 3ea39bcef6

[CyrilleB79]

The failing test is Robot.chromeTests.ARIA treegrid
Seems totally unrelated to this PR.

[AppVeyorBot]

• System test failure
• Build (for testing PR)

See test results for failed build of commit ac7c06ef12

[CyrilleB79]

Oh, I have closed this PR by mistake and then re-opened it. This seems to trigger a new AppVeyor build. Good to know...

Now, another system test is failing: Robot.chromeTests.i7562.
Still unrelated to this PR.

[AppVeyorBot]

• PR introduces Flake8 errors
• Build (for testing PR)

See test results for failed build of commit ccae80cdb0

[AppVeyorBot]

• System test failure
• Build (for testing PR)

See test results for failed build of commit 23be5e7cbe

[seanbudd]

Thanks @CyrilleB79 for this, and for your patience dealing with our randomly failing system tests.

Here's the excel file I used to test with
test-12264.xlsx