feat: contain mobile Device Setup focus (Closes #1134)

tests/e2e/test_mobile_home_bootstrap_release.py

@@ -148,12 +148,24 @@ def test_release_artifact_bootstraps_mobile_home_and_returns_from_insights(
             expect(page.locator("#device-setup-sheet")).to_be_visible()
             expect(page.locator("#device-storage-heading")).to_have_text("Private device storage")
             expect(page.locator("#device-storage-detail")).to_contain_text("private work records")
+            expect(page.locator("body > header")).to_have_attribute("inert", "")
+            expect(page.locator("main")).to_have_attribute("inert", "")
+            expect(dock).to_have_attribute("inert", "")
+            expect(page.locator("#close-device-setup")).to_be_focused()
+            page.keyboard.press("Shift+Tab")
+            expect(page.locator("#clear-private-device-data")).to_be_focused()
+            page.keyboard.press("Tab")
+            expect(page.locator("#close-device-setup")).to_be_focused()
             for selector in ("#clear-device-caches", "#clear-private-device-data"):
                 bounds = page.locator(selector).bounding_box()
                 assert bounds and bounds["height"] >= 44
             assert page.evaluate("document.documentElement.scrollWidth <= window.innerWidth")
-            page.locator("#close-device-setup").click()
+            page.go_back()
             expect(page.locator("#device-setup-sheet")).to_be_hidden()
+            expect(page.locator("#open-device-setup")).to_be_focused()
+            expect(page.locator("body > header")).not_to_have_attribute("inert", "")
+            expect(page.locator("main")).not_to_have_attribute("inert", "")
+            expect(dock).not_to_have_attribute("inert", "")
 
             page.locator("#active-devices").click()
             expect(page.locator("#active-devices-sheet")).to_be_visible()

tests/test_mobile_device_setup.py

@@ -10,7 +10,7 @@ def run_scenario(script: str) -> dict:
     harness = r"""
 const createMobileDeviceSetup = require(__MODULE__);
 class FakeTarget {
-  constructor() { this.listeners = {}; this.hidden = false; this.disabled = false; this.textContent = ''; }
+  constructor() { this.listeners = {}; this.hidden = false; this.disabled = false; this.textContent = ''; this.inert = false; }
   addEventListener(name, callback) { (this.listeners[name] ||= []).push(callback); }
   async dispatch(name, event = {}) { for (const callback of this.listeners[name] || []) await callback(event); }
   focus() { state.focused = this; }
@@ -39,6 +39,15 @@ const promptSummary = new FakeTarget();
 const promptLauncher = new FakeTarget();
 const promptDismiss = new FakeTarget();
 const returnButton = new FakeTarget();
+const backgroundHeader = new FakeTarget();
+const backgroundMain = new FakeTarget(); backgroundMain.inert = true;
+sheet.querySelectorAll = () => [closeButton, installButton, offlineButton, returnButton];
+const historyTarget = new FakeTarget();
+const history = {
+  state:{section:'home'},
+  pushState(state) { this.state = state; },
+  back() { this.state = {section:'home'}; historyTarget.dispatch('popstate', {state:this.state}); },
+};
 let now = 1000;
 const promptStorage = {
   values:{},
@@ -57,6 +66,8 @@ const setup = createMobileDeviceSetup({
   installStatus, offlineStatus, protectionStatus, pushStatus, deadlineStatus, readyStatus, escapeTarget,
   promptCard, promptSummary, promptLauncher, promptDismiss,
   returnButton, isMobile:() => true,
+  backgroundElements:[backgroundHeader, backgroundMain],
+  history, historyTarget,
   timerView:{
     beginDetour:reason => { state.events.push('pause'); state.beginCalls.push(reason); return {reason}; },
     finishDetour:() => { state.events.push('resume'); state.finishCalls += 1; },
@@ -206,6 +217,60 @@ process.stdout.write(JSON.stringify({
     assert result == {"hidden": True, "launcherFocused": True}
 
 
+def test_open_setup_contains_focus_and_restores_background_inert_state():
+    result = run_scenario("""
+await launcher.dispatch('click', {currentTarget:launcher});
+state.focused = returnButton;
+let preventedForward = false;
+await escapeTarget.dispatch('keydown', {key:'Tab', target:returnButton, preventDefault(){preventedForward=true;}});
+const forwardFocus = state.focused === closeButton;
+state.focused = closeButton;
+let preventedReverse = false;
+await escapeTarget.dispatch('keydown', {key:'Tab', shiftKey:true, target:closeButton, preventDefault(){preventedReverse=true;}});
+const reverseFocus = state.focused === returnButton;
+const inertWhileOpen = [backgroundHeader.inert, backgroundMain.inert];
+await closeButton.dispatch('click');
+process.stdout.write(JSON.stringify({
+  preventedForward, forwardFocus, preventedReverse, reverseFocus,
+  inertWhileOpen,
+  inertAfterClose:[backgroundHeader.inert, backgroundMain.inert],
+  launcherFocused:state.focused === launcher,
+}));
+""")
+
+    assert result == {
+        "preventedForward": True,
+        "forwardFocus": True,
+        "preventedReverse": True,
+        "reverseFocus": True,
+        "inertWhileOpen": [True, True],
+        "inertAfterClose": [False, True],
+        "launcherFocused": True,
+    }
+
+
+def test_browser_back_closes_setup_and_restores_launcher_focus():
+    result = run_scenario("""
+await launcher.dispatch('click', {currentTarget:launcher});
+const marked = history.state.deviceSetup === true;
+history.back();
+await new Promise(resolve => setImmediate(resolve));
+process.stdout.write(JSON.stringify({
+  marked,
+  hidden:sheet.hidden,
+  backgroundReleased:backgroundHeader.inert === false,
+  launcherFocused:state.focused === launcher,
+}));
+""")
+
+    assert result == {
+        "marked": True,
+        "hidden": True,
+        "backgroundReleased": True,
+        "launcherFocused": True,
+    }
+
+
 def test_mobile_setup_pauses_before_readiness_and_each_exit_resumes_once():
     result = run_scenario("""
 state.events = [];