diff --git a/lib/semaphore.js b/lib/semaphore.js
index b8cd0b8..0c0a179 100644
--- a/lib/semaphore.js
+++ b/lib/semaphore.js
@@ -7,7 +7,7 @@ class Semaphore {
   constructor(limit) {
     this.limit = Math.max(1, limit || 1);
     this.active = 0;
-    this.queue = []; // { resolve, reject, onAbort? }
+    this.queue = []; // { resolve, reject, signal?, onAbort? }
   }
 
   acquire(signal) {
@@ -26,8 +26,8 @@ class Semaphore {
       const entry = { resolve, reject };
 
       if (signal) {
+        entry.signal = signal;
         entry.onAbort = () => {
-          // Remove from queue without granting a slot
           const idx = this.queue.indexOf(entry);
           if (idx !== -1) this.queue.splice(idx, 1);
           reject(new Error('Aborted'));
@@ -39,14 +39,16 @@ class Semaphore {
     });
   }
 
+  _cleanupEntry(entry) {
+    if (entry.signal && entry.onAbort) {
+      entry.signal.removeEventListener('abort', entry.onAbort);
+    }
+  }
+
   release() {
     if (this.queue.length > 0) {
-      // Don't decrement active — hand slot directly to next waiter
       const entry = this.queue.shift();
-      // Clean up abort listener
-      if (entry.onAbort) {
-        // Entry was granted a slot; no need for abort listener anymore
-      }
+      this._cleanupEntry(entry);
       entry.resolve();
     } else {
       this.active = Math.max(0, this.active - 1);
@@ -55,10 +57,10 @@ class Semaphore {
 
   updateLimit(newLimit) {
     this.limit = Math.max(1, newLimit || 1);
-    // If new limit is higher, wake up waiting tasks
     while (this.active < this.limit && this.queue.length > 0) {
       this.active++;
       const entry = this.queue.shift();
+      this._cleanupEntry(entry);
       entry.resolve();
     }
   }
diff --git a/package.json b/package.json
index 0c25f30..4c219ef 100644
--- a/package.json
+++ b/package.json
@@ -5,6 +5,7 @@
   "main": "main.js",
   "scripts": {
     "start": "electron .",
+    "test": "node --test tests/",
     "dist": "electron-builder --win",
     "release:win": "electron-builder --publish never --win nsis portable",
     "release:gitea": "node scripts/release_gitea.mjs"
diff --git a/tests/config-store.test.js b/tests/config-store.test.js
new file mode 100644
index 0000000..212cd66
--- /dev/null
+++ b/tests/config-store.test.js
@@ -0,0 +1,123 @@
+const { describe, it, beforeEach, afterEach } = require('node:test');
+const assert = require('node:assert/strict');
+const fs = require('fs');
+const path = require('path');
+const os = require('os');
+const ConfigStore = require('../lib/config-store');
+
+let tmpDir;
+let store;
+
+function createStore() {
+  const fakeApp = {
+    isPackaged: false,
+    getPath: () => tmpDir
+  };
+  // ConfigStore uses path.join(__dirname, '..') for non-packaged
+  // We override by setting filePath directly
+  store = new ConfigStore(fakeApp);
+  store.filePath = path.join(tmpDir, 'electron-config.json');
+  return store;
+}
+
+describe('ConfigStore', () => {
+  beforeEach(() => {
+    tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), 'cfg-test-'));
+    store = createStore();
+  });
+
+  afterEach(() => {
+    fs.rmSync(tmpDir, { recursive: true, force: true });
+  });
+
+  it('load returns defaults when file does not exist', () => {
+    const config = store.load();
+    assert.ok(config.hosters);
+    assert.ok(config.hosters['doodstream.com']);
+    assert.ok(config.hosters['voe.sx']);
+    assert.ok(config.hosters['vidmoly.me']);
+    assert.ok(config.hosters['byse.sx']);
+    assert.ok(config.hosterSettings);
+    assert.equal(config.hosterSettings['doodstream.com'].retries, 3);
+    assert.equal(config.hosterSettings['doodstream.com'].parallelCount, 2);
+    assert.equal(config.globalSettings.alwaysOnTop, false);
+    assert.equal(config.globalSettings.shutdownAfterFinish, 'nothing');
+    assert.deepEqual(config.history, []);
+  });
+
+  it('save then load round-trips', () => {
+    store.save({ hosters: { 'doodstream.com': { enabled: true, apiKey: 'test-key-123' } } });
+    const config = store.load();
+    assert.equal(config.hosters['doodstream.com'].apiKey, 'test-key-123');
+  });
+
+  it('load merges with defaults for missing hosters', () => {
+    // Write partial config
+    fs.writeFileSync(store.filePath, JSON.stringify({
+      hosters: { 'doodstream.com': { apiKey: 'abc' } }
+    }), 'utf-8');
+
+    const config = store.load();
+    assert.equal(config.hosters['doodstream.com'].apiKey, 'abc');
+    // Other hosters should still have defaults
+    assert.equal(config.hosters['voe.sx'].enabled, true);
+    assert.equal(config.hosters['voe.sx'].apiKey, '');
+  });
+
+  it('hosterSettings merge fills gaps with defaults', () => {
+    fs.writeFileSync(store.filePath, JSON.stringify({
+      hosterSettings: { 'voe.sx': { retries: 5 } }
+    }), 'utf-8');
+
+    const config = store.load();
+    assert.equal(config.hosterSettings['voe.sx'].retries, 5);
+    assert.equal(config.hosterSettings['voe.sx'].parallelCount, 2); // default
+    assert.equal(config.hosterSettings['voe.sx'].maxSpeedKbs, 0); // default
+  });
+
+  it('save only updates provided sections', () => {
+    // Save hoster settings first
+    store.save({ hosterSettings: { 'doodstream.com': { retries: 10, maxSpeedKbs: 0, parallelCount: 2, restartBelowKbs: 0, timeIntervalSec: 0, maxSizeMb: 0 } } });
+    // Save hosters credentials separately
+    store.save({ hosters: { 'doodstream.com': { enabled: true, apiKey: 'key123' } } });
+
+    const config = store.load();
+    assert.equal(config.hosters['doodstream.com'].apiKey, 'key123');
+    assert.equal(config.hosterSettings['doodstream.com'].retries, 10); // preserved
+  });
+
+  it('appendHistory adds entries and caps at 100', () => {
+    for (let i = 0; i < 105; i++) {
+      store.appendHistory({ id: `batch-${i}`, timestamp: new Date().toISOString(), files: [] });
+    }
+    const history = store.loadHistory();
+    assert.equal(history.length, 100);
+    assert.equal(history[0].id, 'batch-5'); // first 5 dropped
+    assert.equal(history[99].id, 'batch-104');
+  });
+
+  it('clearHistory empties the array', () => {
+    store.appendHistory({ id: 'test', files: [] });
+    assert.equal(store.loadHistory().length, 1);
+    store.clearHistory();
+    assert.equal(store.loadHistory().length, 0);
+  });
+
+  it('corrupted JSON falls back to defaults', () => {
+    fs.writeFileSync(store.filePath, '{invalid json!!!', 'utf-8');
+    const config = store.load();
+    assert.ok(config.hosters);
+    assert.ok(config.hosterSettings);
+    assert.deepEqual(config.history, []);
+  });
+
+  it('globalSettings merge preserves partial values', () => {
+    fs.writeFileSync(store.filePath, JSON.stringify({
+      globalSettings: { alwaysOnTop: true }
+    }), 'utf-8');
+
+    const config = store.load();
+    assert.equal(config.globalSettings.alwaysOnTop, true);
+    assert.equal(config.globalSettings.shutdownAfterFinish, 'nothing'); // default
+  });
+});
diff --git a/tests/semaphore.test.js b/tests/semaphore.test.js
new file mode 100644
index 0000000..3763ac0
--- /dev/null
+++ b/tests/semaphore.test.js
@@ -0,0 +1,165 @@
+const { describe, it } = require('node:test');
+const assert = require('node:assert/strict');
+const Semaphore = require('../lib/semaphore');
+
+describe('Semaphore', () => {
+  it('clamps limit to at least 1', () => {
+    assert.equal(new Semaphore(0).limit, 1);
+    assert.equal(new Semaphore(-5).limit, 1);
+    assert.equal(new Semaphore(undefined).limit, 1);
+    assert.equal(new Semaphore(3).limit, 3);
+  });
+
+  it('acquire resolves immediately when slots available', async () => {
+    const sem = new Semaphore(2);
+    await sem.acquire();
+    await sem.acquire();
+    assert.equal(sem.active, 2);
+  });
+
+  it('acquire blocks when all slots taken', async () => {
+    const sem = new Semaphore(1);
+    await sem.acquire();
+
+    let resolved = false;
+    const p = sem.acquire().then(() => { resolved = true; });
+
+    // Give microtask a chance to resolve
+    await new Promise(r => setTimeout(r, 10));
+    assert.equal(resolved, false, 'should not resolve while slot is taken');
+    assert.equal(sem.pending, 1);
+
+    sem.release();
+    await p;
+    assert.equal(resolved, true);
+  });
+
+  it('FIFO ordering', async () => {
+    const sem = new Semaphore(1);
+    await sem.acquire(); // take the one slot
+
+    const order = [];
+    const p1 = sem.acquire().then(() => order.push(1));
+    const p2 = sem.acquire().then(() => order.push(2));
+    const p3 = sem.acquire().then(() => order.push(3));
+
+    assert.equal(sem.pending, 3);
+
+    sem.release(); await p1;
+    sem.release(); await p2;
+    sem.release(); await p3;
+
+    assert.deepEqual(order, [1, 2, 3]);
+  });
+
+  it('release with no waiters decrements active', async () => {
+    const sem = new Semaphore(2);
+    await sem.acquire();
+    assert.equal(sem.active, 1);
+    sem.release();
+    assert.equal(sem.active, 0);
+  });
+
+  it('release never goes below 0', () => {
+    const sem = new Semaphore(2);
+    sem.release();
+    assert.equal(sem.active, 0);
+    sem.release();
+    assert.equal(sem.active, 0);
+  });
+
+  it('acquire rejects immediately if signal already aborted', async () => {
+    const sem = new Semaphore(2);
+    const ac = new AbortController();
+    ac.abort();
+
+    await assert.rejects(sem.acquire(ac.signal), /Aborted/);
+    assert.equal(sem.active, 0, 'no slot should be acquired');
+  });
+
+  it('abort while waiting in queue removes entry and rejects', async () => {
+    const sem = new Semaphore(1);
+    await sem.acquire(); // take the slot
+
+    const ac = new AbortController();
+    const p = sem.acquire(ac.signal);
+
+    assert.equal(sem.pending, 1);
+    ac.abort();
+    await assert.rejects(p, /Aborted/);
+    assert.equal(sem.pending, 0, 'entry should be removed from queue');
+
+    // Release original slot - should not cause issues
+    sem.release();
+    assert.equal(sem.active, 0);
+  });
+
+  it('abort listener is cleaned up when slot is granted via release', async () => {
+    const sem = new Semaphore(1);
+    await sem.acquire();
+
+    const ac = new AbortController();
+    let rejected = false;
+    const p = sem.acquire(ac.signal).catch(() => { rejected = true; });
+
+    sem.release(); // grants slot to the waiter
+    await p;
+
+    // Now abort after the slot was already granted
+    ac.abort();
+    await new Promise(r => setTimeout(r, 10));
+    assert.equal(rejected, false, 'reject should not fire after slot was granted');
+  });
+
+  it('updateLimit wakes waiters', async () => {
+    const sem = new Semaphore(1);
+    await sem.acquire();
+
+    const resolved = [];
+    const p1 = sem.acquire().then(() => resolved.push(1));
+    const p2 = sem.acquire().then(() => resolved.push(2));
+
+    sem.updateLimit(3);
+    await Promise.all([p1, p2]);
+    assert.deepEqual(resolved, [1, 2]);
+  });
+
+  it('updateLimit to lower value does not kill active slots', async () => {
+    const sem = new Semaphore(3);
+    await sem.acquire();
+    await sem.acquire();
+    await sem.acquire();
+    assert.equal(sem.active, 3);
+
+    sem.updateLimit(1);
+    assert.equal(sem.active, 3, 'existing active slots should not be evicted');
+
+    sem.release();
+    sem.release();
+    sem.release();
+    assert.equal(sem.active, 0);
+
+    // Now only 1 slot should be available
+    await sem.acquire();
+    let blocked = false;
+    const p = sem.acquire().then(() => { blocked = true; });
+    await new Promise(r => setTimeout(r, 10));
+    assert.equal(blocked, false, 'should block at limit 1');
+    sem.release();
+    await p;
+  });
+
+  it('pending getter tracks queue size', async () => {
+    const sem = new Semaphore(1);
+    assert.equal(sem.pending, 0);
+
+    await sem.acquire();
+    sem.acquire(); // blocked
+    sem.acquire(); // blocked
+    assert.equal(sem.pending, 2);
+
+    sem.release();
+    await new Promise(r => setTimeout(r, 5));
+    assert.equal(sem.pending, 1);
+  });
+});
diff --git a/tests/throttle.test.js b/tests/throttle.test.js
new file mode 100644
index 0000000..b692058
--- /dev/null
+++ b/tests/throttle.test.js
@@ -0,0 +1,86 @@
+const { describe, it } = require('node:test');
+const assert = require('node:assert/strict');
+const Throttle = require('../lib/throttle');
+
+describe('Throttle', () => {
+  it('unlimited mode (0) returns immediately', async () => {
+    const t = new Throttle(0);
+    const start = Date.now();
+    await t.consume(10_000_000);
+    assert.ok(Date.now() - start < 50, 'should be instant');
+  });
+
+  it('unlimited with falsy values', async () => {
+    for (const val of [undefined, null, false, 0]) {
+      const t = new Throttle(val);
+      const start = Date.now();
+      await t.consume(1_000_000);
+      assert.ok(Date.now() - start < 50, `should be instant for ${val}`);
+    }
+  });
+
+  it('small consume within initial token budget resolves immediately', async () => {
+    const t = new Throttle(1024 * 1024); // 1 MB/s
+    const start = Date.now();
+    await t.consume(100); // 100 bytes, well within 1MB budget
+    assert.ok(Date.now() - start < 50);
+  });
+
+  it('large consume exceeding tokens introduces delay', async () => {
+    const t = new Throttle(1000); // 1000 bytes/sec
+    // Drain initial tokens
+    await t.consume(1000);
+
+    const start = Date.now();
+    await t.consume(500); // needs ~500ms of refill
+    const elapsed = Date.now() - start;
+    assert.ok(elapsed >= 400, `expected >=400ms, got ${elapsed}ms`);
+    assert.ok(elapsed < 2000, `expected <2000ms, got ${elapsed}ms`);
+  });
+
+  it('aborted signal stops consumption early', async () => {
+    const t = new Throttle(100); // 100 bytes/sec
+    await t.consume(100); // drain budget
+
+    const ac = new AbortController();
+    setTimeout(() => ac.abort(), 100);
+
+    const start = Date.now();
+    await t.consume(10000, ac.signal); // would take ~100s without abort
+    const elapsed = Date.now() - start;
+    assert.ok(elapsed < 1000, `should abort quickly, took ${elapsed}ms`);
+  });
+
+  it('updateRate changes behavior', async () => {
+    const t = new Throttle(100);
+    await t.consume(100); // drain
+
+    t.updateRate(0); // switch to unlimited
+    const start = Date.now();
+    await t.consume(999999);
+    assert.ok(Date.now() - start < 50, 'should be instant after switching to unlimited');
+  });
+
+  it('_refill does not exceed maxBps', () => {
+    const t = new Throttle(1000);
+    t.tokens = 0;
+    t.lastRefill = Date.now() - 60000; // simulate 60 seconds elapsed
+    t._refill();
+    assert.ok(t.tokens <= 1000, `tokens should not exceed maxBps, got ${t.tokens}`);
+  });
+
+  it('concurrent consume calls share the token pool', async () => {
+    const t = new Throttle(2000); // 2000 bytes/sec, initial tokens = 2000
+
+    // Two concurrent consumes of 1000 each - should both fit in initial budget
+    const start = Date.now();
+    await Promise.all([t.consume(1000), t.consume(1000)]);
+    assert.ok(Date.now() - start < 100, 'both should resolve from initial budget');
+
+    // Third consume should need to wait for refill
+    const start2 = Date.now();
+    await t.consume(500);
+    const elapsed = Date.now() - start2;
+    assert.ok(elapsed >= 150, `third consume should wait for refill, took ${elapsed}ms`);
+  });
+});
diff --git a/tests/ui-smoke.js b/tests/ui-smoke.js
new file mode 100644
index 0000000..5929db8
--- /dev/null
+++ b/tests/ui-smoke.js
@@ -0,0 +1,168 @@
+/**
+ * UI smoke test - launches the real app and checks DOM elements via webContents.
+ * Run with: node tests/ui-smoke.js
+ * (This spawns Electron as a child process)
+ */
+const { execSync } = require('child_process');
+const path = require('path');
+const fs = require('fs');
+
+// Create a temp script that the real Electron app will execute via --eval
+const testScript = `
+const { app, BrowserWindow } = require('electron');
+
+// Monkey-patch: after the real window loads, run tests
+const origReady = app.whenReady;
+
+async function runAfterDelay(win, delayMs) {
+  await new Promise(r => setTimeout(r, delayMs));
+  return win;
+}
+
+// Wait for app to be ready, then wait for the real window to load
+setTimeout(async () => {
+  const windows = BrowserWindow.getAllWindows();
+  if (windows.length === 0) { console.log('ERROR: No windows found'); process.exit(1); }
+  const win = windows[0];
+  const wc = win.webContents;
+
+  // Wait for renderer init
+  await new Promise(r => setTimeout(r, 2000));
+
+  let passed = 0;
+  let failed = 0;
+  const results = [];
+
+  function check(name, condition) {
+    if (condition) { passed++; results.push('  PASS: ' + name); }
+    else { failed++; results.push('  FAIL: ' + name); }
+  }
+
+  try {
+    console.log('\\n=== Upload View ===');
+
+    const tabCount = await wc.executeJavaScript('document.querySelectorAll(".tab").length');
+    check('3 tabs exist', tabCount === 3);
+
+    const activeTab = await wc.executeJavaScript('document.querySelector(".tab.active")?.textContent?.trim()');
+    check('Upload tab active by default', activeTab === 'Upload');
+
+    const dropVisible = await wc.executeJavaScript('document.getElementById("dropZone")?.style.display !== "none"');
+    check('Drop zone visible (no files)', dropVisible);
+
+    const queueHidden = await wc.executeJavaScript('document.getElementById("queueContainer")?.style.display');
+    check('Queue hidden (no files)', queueHidden === 'none');
+
+    const chips = await wc.executeJavaScript('document.querySelectorAll(".hoster-chip").length');
+    check('4 hoster chips', chips === 4);
+
+    const startDisabled = await wc.executeJavaScript('document.getElementById("startUploadBtn")?.disabled');
+    check('Start button disabled initially', startDisabled === true);
+
+    const sbState = await wc.executeJavaScript('document.getElementById("sbState")?.textContent');
+    check('Statusbar: Bereit', sbState === 'Bereit');
+
+    const version = await wc.executeJavaScript('document.getElementById("versionLabel")?.textContent');
+    check('Version label present', version && version.startsWith('v'));
+
+    const ctxHidden = await wc.executeJavaScript('document.getElementById("contextMenu")?.style.display');
+    check('Context menu hidden', ctxHidden === 'none');
+
+    console.log('\\n=== Settings View ===');
+
+    await wc.executeJavaScript('document.querySelector(".tab[data-view=\\'settings\\']").click()');
+    await new Promise(r => setTimeout(r, 300));
+
+    const settingsActive = await wc.executeJavaScript('document.getElementById("settings-view")?.classList.contains("active")');
+    check('Settings tab active', settingsActive);
+
+    const panels = await wc.executeJavaScript('document.querySelectorAll(".hoster-settings-panel").length');
+    check('4 hoster panels', panels === 4);
+
+    const hsInputCount = await wc.executeJavaScript('document.querySelectorAll(".hs-input").length');
+    check('24 per-hoster inputs (6x4)', hsInputCount === 24);
+
+    await wc.executeJavaScript('document.querySelector(".hoster-panel-header").click()');
+    await new Promise(r => setTimeout(r, 200));
+
+    const panelBody = await wc.executeJavaScript('document.querySelector(".hoster-panel-body").style.display');
+    check('Panel expands on click', panelBody !== 'none');
+
+    const retries = await wc.executeJavaScript('document.querySelector(".hs-input[data-hs=\\'retries\\']")?.value');
+    check('Retries default 3', retries === '3');
+
+    const parallel = await wc.executeJavaScript('document.querySelector(".hs-input[data-hs=\\'parallelCount\\']")?.value');
+    check('ParallelCount default 2', parallel === '2');
+
+    // Test save
+    await wc.executeJavaScript('document.getElementById("saveSettingsBtn").click()');
+    await new Promise(r => setTimeout(r, 500));
+    const feedback = await wc.executeJavaScript('document.getElementById("saveFeedback")?.textContent');
+    check('Save shows Gespeichert!', feedback === 'Gespeichert!');
+
+    console.log('\\n=== History View ===');
+
+    await wc.executeJavaScript('document.querySelector(".tab[data-view=\\'history\\']").click()');
+    await new Promise(r => setTimeout(r, 1000)); // Wait for async loadHistory
+
+    const historyActive = await wc.executeJavaScript('document.getElementById("history-view")?.classList.contains("active")');
+    check('History tab active', historyActive);
+
+    const emptyState = await wc.executeJavaScript('document.querySelector("#historyContainer .empty-state")?.textContent');
+    check('Empty state or history table shown', emptyState === 'Noch keine Uploads.' || emptyState === undefined);
+
+    console.log('\\n=== Global UI ===');
+
+    const shutdownHidden = await wc.executeJavaScript('document.getElementById("shutdownOverlay")?.style.display');
+    check('Shutdown overlay hidden', shutdownHidden === 'none');
+
+    const toastHidden = await wc.executeJavaScript('!document.getElementById("copyToast")?.classList.contains("show")');
+    check('Copy toast hidden', toastHidden);
+
+    const updateHidden = await wc.executeJavaScript('document.getElementById("updateBanner")?.style.display');
+    check('Update banner hidden', updateHidden === 'none');
+
+  } catch (err) {
+    console.error('Test error:', err.message);
+    failed++;
+  }
+
+  console.log('\\n=== Results ===');
+  results.forEach(r => console.log(r));
+  console.log('\\nTotal: ' + (passed + failed) + ' | Passed: ' + passed + ' | Failed: ' + failed);
+
+  if (failed > 0) process.exitCode = 1;
+  app.quit();
+}, 5000);
+`;
+
+// Write the injection script
+const injectPath = path.join(__dirname, '_ui-inject.tmp.js');
+fs.writeFileSync(injectPath, testScript, 'utf-8');
+
+// Run the real app with the injection
+try {
+  const electronPath = path.join(__dirname, '..', 'node_modules', '.bin', 'electron');
+  const mainPath = path.join(__dirname, '..', 'main.js');
+
+  // We'll use --require to inject the test after the main process loads
+  const result = execSync(
+    `"${electronPath}" --require "${injectPath}" "${mainPath}"`,
+    { cwd: path.join(__dirname, '..'), timeout: 20000, encoding: 'utf-8', stdio: ['pipe', 'pipe', 'pipe'] }
+  );
+  console.log(result);
+} catch (err) {
+  // timeout or exit code - still print output
+  if (err.stdout) console.log(err.stdout);
+  if (err.stderr) {
+    const filtered = err.stderr.split('\n')
+      .filter(l => !l.includes('cache_util') && !l.includes('disk_cache') && !l.includes('gpu_disk_cache'))
+      .join('\n');
+    if (filtered.trim()) console.error(filtered);
+  }
+  if (err.status && err.status !== 0 && !err.killed) {
+    process.exit(err.status);
+  }
+} finally {
+  try { fs.unlinkSync(injectPath); } catch {}
+}
diff --git a/tests/upload-manager.test.js b/tests/upload-manager.test.js
new file mode 100644
index 0000000..eb817c5
--- /dev/null
+++ b/tests/upload-manager.test.js
@@ -0,0 +1,243 @@
+const { describe, it, mock, beforeEach } = require('node:test');
+const assert = require('node:assert/strict');
+const path = require('path');
+const { EventEmitter } = require('events');
+
+// We need to mock fs.statSync and the hoster upload functions before requiring upload-manager
+// Use node:test mock.module (available in Node 22+)
+
+describe('UploadManager', () => {
+  let UploadManager;
+  let mockUploadFile;
+  let fakeFileSize;
+
+  beforeEach(() => {
+    fakeFileSize = 1024 * 1024; // 1 MB default
+
+    // Clear module cache for fresh mocks each test
+    delete require.cache[require.resolve('../lib/upload-manager')];
+
+    // Mock the hosters module
+    mockUploadFile = mock.fn(async (hoster, filePath, apiKey, onProgress, signal, throttle) => {
+      // Simulate upload progress
+      if (onProgress) {
+        onProgress(fakeFileSize / 2, fakeFileSize);
+        onProgress(fakeFileSize, fakeFileSize);
+      }
+      return { download_url: `https://${hoster}/test123`, embed_url: null, file_code: 'test123' };
+    });
+
+    // Override require for hosters
+    const origRequire = module.constructor.prototype.require;
+    const hosters = require('../lib/hosters');
+    hosters.uploadFile = mockUploadFile;
+
+    // Mock fs.statSync for test file paths
+    const fs = require('fs');
+    const origStatSync = fs.statSync;
+    fs.statSync = function(p) {
+      if (typeof p === 'string' && p.startsWith('/test/')) {
+        return { size: fakeFileSize };
+      }
+      return origStatSync.call(this, p);
+    };
+
+    UploadManager = require('../lib/upload-manager');
+  });
+
+  it('emits progress events for each task', async () => {
+    const mgr = new UploadManager({});
+    const events = [];
+    mgr.on('progress', (data) => events.push(data));
+
+    await mgr.startBatch([
+      { file: '/test/video1.mp4', hoster: 'doodstream.com', apiKey: 'key1' }
+    ]);
+
+    const statuses = events.map(e => e.status);
+    assert.ok(statuses.includes('queued'), 'should have queued status');
+    assert.ok(statuses.includes('done'), 'should have done status');
+  });
+
+  it('emits batch-done with correct summary', async () => {
+    const mgr = new UploadManager({});
+    let summary = null;
+    mgr.on('batch-done', (s) => { summary = s; });
+
+    await mgr.startBatch([
+      { file: '/test/video1.mp4', hoster: 'doodstream.com', apiKey: 'key1' },
+      { file: '/test/video2.mp4', hoster: 'doodstream.com', apiKey: 'key1' }
+    ]);
+
+    assert.ok(summary);
+    assert.equal(summary.total, 2);
+    assert.equal(summary.succeeded, 2);
+    assert.equal(summary.failed, 0);
+    assert.equal(summary.files.length, 2);
+  });
+
+  it('retries on failure then succeeds', async () => {
+    let callCount = 0;
+    mockUploadFile.mock.mockImplementation(async (hoster, filePath, apiKey, onProgress) => {
+      callCount++;
+      if (callCount <= 2) throw new Error('network error');
+      if (onProgress) onProgress(fakeFileSize, fakeFileSize);
+      return { download_url: 'https://test/ok', embed_url: null, file_code: 'ok' };
+    });
+
+    const mgr = new UploadManager({ 'doodstream.com': { retries: 3, parallelCount: 1, maxSpeedKbs: 0, restartBelowKbs: 0, timeIntervalSec: 0, maxSizeMb: 0 } });
+    const statuses = [];
+    mgr.on('progress', (d) => statuses.push(d.status));
+
+    await mgr.startBatch([
+      { file: '/test/video.mp4', hoster: 'doodstream.com', apiKey: 'key1' }
+    ]);
+
+    assert.ok(statuses.includes('retrying'), 'should show retrying status');
+    assert.ok(statuses.includes('done'), 'should eventually succeed');
+    assert.equal(callCount, 3);
+  });
+
+  it('exhausted retries result in error', async () => {
+    mockUploadFile.mock.mockImplementation(async () => {
+      throw new Error('permanent failure');
+    });
+
+    const mgr = new UploadManager({ 'doodstream.com': { retries: 1, parallelCount: 1, maxSpeedKbs: 0, restartBelowKbs: 0, timeIntervalSec: 0, maxSizeMb: 0 } });
+    let summary = null;
+    mgr.on('batch-done', (s) => { summary = s; });
+
+    await mgr.startBatch([
+      { file: '/test/video.mp4', hoster: 'doodstream.com', apiKey: 'key1' }
+    ]);
+
+    assert.ok(summary);
+    assert.equal(summary.failed, 1);
+    assert.equal(summary.succeeded, 0);
+  });
+
+  it('cancel aborts running uploads', async () => {
+    mockUploadFile.mock.mockImplementation(async (hoster, filePath, apiKey, onProgress, signal) => {
+      // Simulate a slow upload
+      await new Promise((resolve, reject) => {
+        const timer = setTimeout(() => resolve({ download_url: 'x', embed_url: null, file_code: 'x' }), 10000);
+        if (signal) signal.addEventListener('abort', () => { clearTimeout(timer); reject(new Error('Aborted')); });
+      });
+    });
+
+    const mgr = new UploadManager({});
+    let batchDone = false;
+    mgr.on('batch-done', () => { batchDone = true; });
+
+    const batchPromise = mgr.startBatch([
+      { file: '/test/video.mp4', hoster: 'doodstream.com', apiKey: 'key1' }
+    ]);
+
+    // Wait a bit then cancel
+    await new Promise(r => setTimeout(r, 100));
+    mgr.cancel();
+
+    await batchPromise;
+    assert.equal(mgr.running, false);
+    assert.ok(batchDone, 'batch-done should be emitted even after cancel');
+  });
+
+  it('maxSizeMb filter skips oversized files', async () => {
+    fakeFileSize = 5 * 1024 * 1024; // 5 MB
+
+    const mgr = new UploadManager({ 'doodstream.com': { retries: 0, parallelCount: 1, maxSpeedKbs: 0, restartBelowKbs: 0, timeIntervalSec: 0, maxSizeMb: 1 } });
+    const statuses = [];
+    mgr.on('progress', (d) => statuses.push(d.status));
+
+    await mgr.startBatch([
+      { file: '/test/big.mp4', hoster: 'doodstream.com', apiKey: 'key1' }
+    ]);
+
+    assert.ok(statuses.includes('skipped'), 'oversized file should be skipped');
+    assert.ok(!statuses.includes('uploading'), 'should not attempt upload');
+  });
+
+  it('per-hoster semaphore limits concurrency', async () => {
+    let concurrent = 0;
+    let maxConcurrent = 0;
+
+    mockUploadFile.mock.mockImplementation(async (hoster, filePath, apiKey, onProgress, signal) => {
+      concurrent++;
+      maxConcurrent = Math.max(maxConcurrent, concurrent);
+      await new Promise(r => setTimeout(r, 50));
+      concurrent--;
+      if (onProgress) onProgress(fakeFileSize, fakeFileSize);
+      return { download_url: 'https://test/ok', embed_url: null, file_code: 'ok' };
+    });
+
+    const mgr = new UploadManager({ 'doodstream.com': { retries: 0, parallelCount: 1, maxSpeedKbs: 0, restartBelowKbs: 0, timeIntervalSec: 0, maxSizeMb: 0 } });
+
+    await mgr.startBatch([
+      { file: '/test/a.mp4', hoster: 'doodstream.com', apiKey: 'k' },
+      { file: '/test/b.mp4', hoster: 'doodstream.com', apiKey: 'k' },
+      { file: '/test/c.mp4', hoster: 'doodstream.com', apiKey: 'k' }
+    ]);
+
+    assert.equal(maxConcurrent, 1, 'should only run 1 upload at a time');
+  });
+
+  it('_combineSignals propagates abort from either source', () => {
+    const mgr = new UploadManager({});
+    const ac1 = new AbortController();
+    const ac2 = new AbortController();
+
+    const combined = mgr._combineSignals(ac1.signal, ac2.signal);
+    assert.equal(combined.aborted, false);
+
+    ac2.abort();
+    assert.equal(combined.aborted, true);
+  });
+
+  it('_combineSignals returns aborted signal if input already aborted', () => {
+    const mgr = new UploadManager({});
+    const ac1 = new AbortController();
+    ac1.abort();
+    const ac2 = new AbortController();
+
+    const combined = mgr._combineSignals(ac1.signal, ac2.signal);
+    assert.equal(combined.aborted, true);
+  });
+
+  it('_sleep resolves after delay', async () => {
+    const mgr = new UploadManager({});
+    const start = Date.now();
+    await mgr._sleep(100);
+    assert.ok(Date.now() - start >= 90);
+  });
+
+  it('_sleep rejects on abort', async () => {
+    const mgr = new UploadManager({});
+    const ac = new AbortController();
+    setTimeout(() => ac.abort(), 10);
+    await assert.rejects(mgr._sleep(5000, ac.signal), /Aborted/);
+  });
+
+  it('stats event contains expected fields', async () => {
+    // Make upload take long enough for stats interval to fire
+    mockUploadFile.mock.mockImplementation(async (hoster, filePath, apiKey, onProgress, signal) => {
+      await new Promise(r => setTimeout(r, 1500));
+      if (onProgress) onProgress(fakeFileSize, fakeFileSize);
+      return { download_url: 'https://test/ok', embed_url: null, file_code: 'ok' };
+    });
+
+    const mgr = new UploadManager({});
+    const statsEvents = [];
+    mgr.on('stats', (d) => statsEvents.push(d));
+
+    await mgr.startBatch([
+      { file: '/test/video.mp4', hoster: 'doodstream.com', apiKey: 'key1' }
+    ]);
+
+    assert.ok(statsEvents.length > 0, 'should have received stats events');
+    const stat = statsEvents[0];
+    assert.ok('globalSpeedKbs' in stat);
+    assert.ok('totalBytes' in stat);
+    assert.ok('elapsed' in stat);
+    assert.ok('activeJobs' in stat);
+  });
+});