fix: Tasks works with SlrVb's Alternative Checkboxes (#1174)

* vault: Add some sample tasks with different states

* vault: Add "ITS Theme", to allow viewing custom checkboxes

* vault: Add #task tag to Custom Statuses.md

* vault: Add a tasks query showing the custom statuses

* fix: Tasks now honours capitalised custom statuses, such as '- [D]'

* vault: Add snippet 'S - Checkboxes.css'

Downloaded from:
https://github.com/SlRvb/Obsidian--ITS-Theme/blob/5fe6b3f0061e22f29e2c52a658d1b6132d81f24e/Snippets/S%20-%20Checkboxes.css

* Revert "vault: Add "ITS Theme", to allow viewing custom checkboxes"

This reverts commit 6d0ad07.

* vault: Add descriptive text to 'Custom Statuses.md'

* vault: Rename sample to "SlrVb's Alternative Checkboxes.md"

resources/sample_vaults/Tasks-Demo/Manual Testing/SlrVb's Alternative Checkboxes.md

@@ -0,0 +1,54 @@
+# SlrVb's Alternative Checkboxes
+
+## Background
+
+This page demonstrates SlRvb's [Alternate-Checkboxes](https://github.com/SlRvb/Obsidian--ITS-Theme/blob/main/Guide/Alternate-Checkboxes.md) from the [ITS-Theme.](https://github.com/SlRvb/Obsidian--ITS-Theme), with the Tasks plugin installed.
+
+It was created to test the fix for [Tasks Issue #520: In combination with SlrVb's S-Checkbox CSS, Task Plugin breaks that style](https://github.com/obsidian-tasks-group/obsidian-tasks/issues/520).
+
+## How to use this file
+
+### Setup
+
+1. Go to Settings > Appearance > **Enable the 'S - Checkboxes' snippet**
+2. Optionally, install and enable the [Style Settings](obsidian://show-plugin?id=obsidian-style-settings) plugin.
+
+### Use
+
+The tasks below should look like one of the images in the [Alternate Checkboxes documentation](https://github.com/SlRvb/Obsidian--ITS-Theme/blob/main/Guide/Alternate-Checkboxes.md), depending on your display settings.
+
+## One of each task status
+
+- [ ] #task Unchecked
+- [x] #task Regular
+- [X] #task Checked
+- [-] #task Dropped
+- [>] #task Forward
+- [D] #task Defer
+- [?] #task Question
+- [/] #task Half Done
+- [+] #task Add
+- [R] #task Research
+- [!] #task Important
+- [i] #task Idea
+- [B] #task Brainstorm
+- [P] #task Pro
+- [C] #task Con
+- [Q] #task Quote
+- [N] #task Note
+- [b] #task Bookmark
+- [I] #task Information
+- [p] #task Paraphrase
+- [L] #task Location
+- [E] #task Example
+- [A] #task Answer
+- [r] #task Reward
+- [c] #task Choice
+
+## Rendered in Tasks results block
+
+```tasks
+path includes Custom Statuses
+group by filename
+short mode
+```

src/Task.ts

@@ -253,7 +253,8 @@ export class Task {
         const indentation = regexMatch[1];
 
         // Get the status of the task, only todo and done supported.
-        const statusString = regexMatch[2].toLowerCase();
+        // But custom ones are retained and displayed as-is.
+        const statusString = regexMatch[2];
         let status: Status;
         switch (statusString) {
             case ' ':

tests/Task.test.ts

@@ -48,6 +48,17 @@ describe('parsing', () => {
         resetSettings();
     });
 
+    it('supports capitalised status characters', () => {
+        // See https://github.com/obsidian-tasks-group/obsidian-tasks/issues/520
+        // "In combination with SlrVb's S-Checkbox CSS, Task Plugin breaks that style"
+
+        // Act
+        const task = fromLine({ line: '- [D] this is a deferred task' });
+
+        // Assert
+        expect(task!.originalStatusCharacter).toStrictEqual('D');
+    });
+
     it('allows signifier emojis as part of the description', () => {
         // Arrange
         const line = '- [x] this is a ✅ done task 🗓 2021-09-12 ✅ 2021-06-20';