fix(properties): harden progress and torrent diagnostics

src/utils/downloadProgress.test.ts

@@ -1,5 +1,10 @@
 import { describe, expect, it } from 'vitest';
-import { formatDownloadBytes, formatDownloadTotal, resolveDownloadSizeDisplay } from './downloadProgress';
+import {
+  formatDownloadBytes,
+  formatDownloadTotal,
+  resolveDownloadFraction,
+  resolveDownloadSizeDisplay,
+} from './downloadProgress';
 
 describe('download progress size display', () => {
   it('formats byte counts using the binary units used by the download engines', () => {
@@ -44,3 +49,62 @@ describe('download progress size display', () => {
     expect(formatDownloadTotal(display)).toBe('2.40 GB');
   });
 });
+
+describe('resolveDownloadFraction', () => {
+  it('reconstructs paused progress from exact persisted byte counters', () => {
+    expect(resolveDownloadFraction({
+      status: 'paused',
+      downloadedBytes: 662 * 1024 ** 2,
+      totalBytes: 2.94 * 1024 ** 3,
+    })).toBeCloseTo(0.2199, 3);
+  });
+
+  it('uses a live fraction when it is available', () => {
+    expect(resolveDownloadFraction({
+      fraction: 0.37,
+      downloadedBytes: 90,
+      totalBytes: 100,
+      status: 'downloading',
+    })).toBe(0.37);
+  });
+
+  it('does not infer progress from an estimated media total', () => {
+    expect(resolveDownloadFraction({
+      fraction: 0,
+      downloadedBytes: 900,
+      totalBytes: 1000,
+      totalIsEstimate: true,
+      isMedia: true,
+      size: '~1000 B',
+      status: 'paused',
+    })).toBe(0);
+  });
+
+  it('keeps zero at the start and does not divide by an unknown total', () => {
+    expect(resolveDownloadFraction({
+      downloadedBytes: 0,
+      totalBytes: 0,
+      status: 'paused',
+    })).toBe(0);
+    expect(resolveDownloadFraction({
+      downloadedBytes: 500,
+      status: 'paused',
+    })).toBe(0);
+  });
+
+  it('shows completed downloads as complete even when volatile fraction was removed', () => {
+    expect(resolveDownloadFraction({
+      status: 'completed',
+      downloadedBytes: 0,
+      totalBytes: 100,
+    })).toBe(1);
+  });
+
+  it('clamps inconsistent exact byte counters', () => {
+    expect(resolveDownloadFraction({
+      downloadedBytes: 150,
+      totalBytes: 100,
+      status: 'paused',
+    })).toBe(1);
+  });
+});