test: Generate block of help text for embedding in docs

Author: claremacrae

tests/Query/Presets/DocsForPresets.test.presets_help_message.approved.md

@@ -0,0 +1,16 @@
+<!-- placeholder to force blank line before included text -->
+
+```text
+Cannot find preset "xxxx" in the Tasks settings
+The following presets are defined in the Tasks settings:
+  hide_date_fields    : # Hide any values for all date fields...
+  hide_everything     : # Hide everything except description and any tags...
+  hide_non_date_fields: # Hide all the non-date fields, but not tags...
+  hide_query_elements : # Hide postpone, edit and backinks...
+  this_file           : path includes {{query.file.path}}
+  this_folder         : folder includes {{query.file.folder}}
+  this_folder_only    : filter by function task.file.folder === query.file...
+  this_root           : root includes {{query.file.root}}
+```
+
+<!-- placeholder to force blank line after included text -->

tests/Query/Presets/DocsForPresets.test.ts

@@ -1,7 +1,8 @@
 import { MarkdownTable } from '../../../src/lib/MarkdownTable';
-import { defaultPresets } from '../../../src/Query/Presets/Presets';
+import { defaultPresets, unknownPresetErrorMessage } from '../../../src/Query/Presets/Presets';
 import { addBackticks } from '../../Scripting/ScriptingTestHelpers';
 import { verifyMarkdownForDocs } from '../../TestingTools/VerifyMarkdown';
+import { getSettings } from '../../../src/Config/Settings';
 
 function verifyPresetsMarkdownTable(entries: [string, string][]) {
     const table = new MarkdownTable(['Name', 'Instruction(s)']);
@@ -33,3 +34,10 @@ it('daily-note-presets', () => {
 
     verifyPresetsMarkdownTable(Object.entries(dailyNotePresets));
 });
+
+it('presets help message', () => {
+    const { presets } = getSettings();
+    const help = unknownPresetErrorMessage('xxxx', presets);
+    const markdown = ['```text', help, '```'].join('\n');
+    verifyMarkdownForDocs(markdown);
+});