refactor: normalize remaining main runtime dependency setup

src/main/runtime/mpv-subtitle-render-metrics-main-deps.test.ts

@@ -0,0 +1,45 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+import type { MpvSubtitleRenderMetrics } from '../../types';
+import { createBuildUpdateMpvSubtitleRenderMetricsMainDepsHandler } from './mpv-subtitle-render-metrics-main-deps';
+
+const BASE_METRICS: MpvSubtitleRenderMetrics = {
+  subPos: 100,
+  subFontSize: 36,
+  subScale: 1,
+  subMarginY: 0,
+  subMarginX: 0,
+  subFont: '',
+  subSpacing: 0,
+  subBold: false,
+  subItalic: false,
+  subBorderSize: 0,
+  subShadowOffset: 0,
+  subAssOverride: 'yes',
+  subScaleByWindow: true,
+  subUseMargins: true,
+  osdHeight: 0,
+  osdDimensions: null,
+};
+
+test('mpv subtitle render metrics main deps builder maps callbacks', () => {
+  const calls: string[] = [];
+  const deps = createBuildUpdateMpvSubtitleRenderMetricsMainDepsHandler({
+    getCurrentMetrics: () => BASE_METRICS,
+    setCurrentMetrics: () => calls.push('set'),
+    applyPatch: (current, patch) => {
+      calls.push('apply');
+      return { next: { ...current, ...patch }, changed: true };
+    },
+    broadcastMetrics: () => calls.push('broadcast'),
+  })();
+
+  assert.equal(deps.getCurrentMetrics().subPos, 100);
+  deps.setCurrentMetrics(BASE_METRICS);
+  const patched = deps.applyPatch(BASE_METRICS, { subPos: 90 });
+  deps.broadcastMetrics(BASE_METRICS);
+
+  assert.equal(patched.changed, true);
+  assert.equal(patched.next.subPos, 90);
+  assert.deepEqual(calls, ['set', 'apply', 'broadcast']);
+});