Fix Windows mpv logging and add log export (#88)

src/main/runtime/mpv-track-diagnostics.test.ts

@@ -0,0 +1,38 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+import { buildSubtitleTrackDiagnostics } from './mpv-track-diagnostics';
+
+test('buildSubtitleTrackDiagnostics summarizes subtitle tracks without dumping track list', () => {
+  const diagnostics = buildSubtitleTrackDiagnostics(3, [
+    { type: 'video', id: 1, selected: true },
+    { type: 'sub', id: 3, lang: 'ja', selected: true, external: false, codec: 'ass' },
+    { type: 'sub', id: '4', title: 'English', external: true, codec: 'srt' },
+    { type: 'audio', id: 2, lang: 'jpn' },
+  ]);
+
+  assert.deepEqual(diagnostics, {
+    trackListReadable: true,
+    trackCount: 4,
+    subtitleTrackCount: 2,
+    activePrimarySid: 3,
+    selectedSubtitleIds: [3],
+    externalSubtitleCount: 1,
+    internalSubtitleCount: 1,
+    languages: ['ja'],
+    selectedSubtitleLabels: ['internal#3:ja'],
+  });
+});
+
+test('buildSubtitleTrackDiagnostics marks unreadable track list', () => {
+  assert.deepEqual(buildSubtitleTrackDiagnostics(null, null), {
+    trackListReadable: false,
+    trackCount: 0,
+    subtitleTrackCount: 0,
+    activePrimarySid: null,
+    selectedSubtitleIds: [],
+    externalSubtitleCount: 0,
+    internalSubtitleCount: 0,
+    languages: [],
+    selectedSubtitleLabels: [],
+  });
+});