fix(test): read source-level fixtures with line endings normalised

test/audio-device-switch.test.mjs

@@ -11,16 +11,13 @@
  * by permissions - it leaves the interview with no microphone at all, mid-answer, having been
  * asked only to change one.
  */
-import { readFileSync } from 'node:fs';
-
-import { codeOnly, createChecker, methodBody } from './helpers.mjs';
+import { codeOnly, createChecker, methodBody, readSource } from './helpers.mjs';
 
 export async function run() {
   const { check, failures } = createChecker('audio-device-switch');
 
-  const source = readFileSync(
-    new URL('../src/renderer/services/live-transcription.service.ts', import.meta.url),
-    'utf8'
+  const source = readSource(
+    new URL('../src/renderer/services/live-transcription.service.ts', import.meta.url)
   );
 
   const body = methodBody(source, 'async setAudioInputDevice(');
@@ -61,7 +58,10 @@ export async function run() {
   // off - with the config naming the other one. The UI disables the picker while a swap is in
   // flight, but that is a guard in a different layer from the bug.
   const bodyCode = codeOnly(body);
-  check('a generation is taken before the awaits', /const seq = \+\+this\.micSwitchSeq;/.test(bodyCode));
+  check(
+    'a generation is taken before the awaits',
+    /const seq = \+\+this\.micSwitchSeq;/.test(bodyCode)
+  );
   check(
     'the generation is taken before getUserMedia',
     bodyCode.indexOf('this.micSwitchSeq') < bodyCode.indexOf('getUserMedia')

test/helpers.mjs

@@ -109,6 +109,22 @@ export function createChecker(name) {
   };
 }
 
+/**
+ * Read a source file for the source-level checks, with line endings normalised.
+ *
+ * `core.autocrlf` is true and there is no `.gitattributes`, so a checkout on Windows - which is
+ * where this project is developed - materialises these files with CRLF while CI materialises
+ * them with LF. Any anchor containing a literal newline therefore matches on the runner and
+ * fails on the developer's machine, which is the worst direction for it to fail in: green CI,
+ * and a suite that looks broken to whoever just pulled.
+ *
+ * Normalised on read rather than making each matcher line-ending aware, because the matchers are
+ * written against the source as it reads on screen and that is the useful thing about them.
+ */
+export function readSource(url) {
+  return fs.readFileSync(url, 'utf8').replace(/\r\n?/g, '\n');
+}
+
 /**
  * Strip comments from TypeScript source before matching against it.
  *

test/language-switch.test.mjs

@@ -15,18 +15,21 @@
  * but the hook only sets that after awaiting the config write, so a second pick lands in
  * between. That is a guard in a different layer from the bug, which is why it is not the fix.
  */
-import { readFileSync } from 'node:fs';
-
-import { codeOnly, createChecker, methodBody } from './helpers.mjs';
+import { codeOnly, createChecker, methodBody, readSource } from './helpers.mjs';
 
 export async function run() {
   const { check, failures } = createChecker('language-switch');
 
-  const source = readFileSync(
-    new URL('../src/renderer/services/live-transcription.service.ts', import.meta.url),
-    'utf8'
+  const source = readSource(
+    new URL('../src/renderer/services/live-transcription.service.ts', import.meta.url)
   );
 
+  // The anchors below contain literal newlines, which is only safe because `readSource`
+  // normalises: `core.autocrlf` is on with no `.gitattributes`, so this source arrives CRLF on a
+  // Windows checkout and LF in CI. Read raw, every one of them matches on the runner and fails
+  // on the machine the project is developed on.
+  check('the source is read with its line endings normalised', !source.includes('\r'));
+
   // Both classes declare `async setLanguage(language: Language)`. The channel's is the first in
   // the file and the service's wraps it, so they are picked apart by what follows the brace.
   const body = methodBody(source, 'async setLanguage(language: Language): Promise<void> {\n    if');
@@ -143,10 +146,7 @@ export async function run() {
   // switch the user has already moved off clears the warning raised by the one that replaced it
   // and re-enables the trigger while that one is still reconnecting.
   const hook = codeOnly(
-    readFileSync(
-      new URL('../src/renderer/hooks/use-interview-language.ts', import.meta.url),
-      'utf8'
-    )
+    readSource(new URL('../src/renderer/hooks/use-interview-language.ts', import.meta.url))
   );
   check('the hook takes a generation per switch', /const seq = \+\+switchSeq\.current;/.test(hook));
   check(
@@ -165,10 +165,7 @@ export async function run() {
   // Its sibling has the identical shape and the identical race - `micSwitchSeq` abandons a
   // superseded swap in the service, and the hook has to stop reporting on it here.
   const deviceHook = codeOnly(
-    readFileSync(
-      new URL('../src/renderer/hooks/use-audio-input-device.ts', import.meta.url),
-      'utf8'
-    )
+    readSource(new URL('../src/renderer/hooks/use-audio-input-device.ts', import.meta.url))
   );
   check(
     'the microphone hook takes the same guard',

test/language.test.mjs

@@ -5,9 +5,7 @@
  * that a stored language actually reaches the request bodies, and that an unknown one resolves to
  * English here rather than travelling to the backend and the ASR URL.
  */
-import { readFileSync } from 'node:fs';
-
-import { createChecker, loadMain } from './helpers.mjs';
+import { createChecker, loadMain, readSource } from './helpers.mjs';
 
 export async function run() {
   const { check, failures } = createChecker('language');
@@ -37,10 +35,7 @@ export async function run() {
   // no renderer entry renders a blank trigger, and a renderer entry with no enum member is an
   // option that resolves straight back to English when picked. The renderer source is read as
   // text because it is never built into electron-dist, which is all `loadMain` can reach.
-  const rendererSource = readFileSync(
-    new URL('../src/renderer/types/language.ts', import.meta.url),
-    'utf8'
-  );
+  const rendererSource = readSource(new URL('../src/renderer/types/language.ts', import.meta.url));
   const rendererCodes = [...rendererSource.matchAll(/code: Language\.\w+, name: '/g)].length;
   const rendererEnum = [...rendererSource.matchAll(/^  \w+ = '([a-z]{2})',$/gm)].map((m) => m[1]);
 

test/rtl-rendering.test.mjs

@@ -17,11 +17,9 @@
  * Source-level checks, like `audio-device-switch.test.mjs`: this is renderer code and the
  * renderer has no runtime harness in this directory.
  */
-import { readFileSync } from 'node:fs';
+import { codeOnly, createChecker, readSource } from './helpers.mjs';
 
-import { codeOnly, createChecker } from './helpers.mjs';
-
-const read = (path) => codeOnly(readFileSync(new URL(path, import.meta.url), 'utf8'));
+const read = (path) => codeOnly(readSource(new URL(path, import.meta.url)));
 
 export async function run() {
   const { check, failures } = createChecker('rtl-rendering');