diff --git a/integration_test/smoke_test.dart b/integration_test/smoke_test.dart
index a726db8a..0b4b0025 100644
--- a/integration_test/smoke_test.dart
+++ b/integration_test/smoke_test.dart
@@ -133,13 +133,20 @@ void main() {
   /// Onboarding's Continue is dead until its controller accepts the answer, so
   /// a walk that taps on the frame after choosing taps nothing at all — and
   /// `tap` on a disabled button succeeds, which is the silent failure again.
-  Finder liveButton(String label) => find.byWidgetPredicate(
-    (widget) =>
-        widget is FilledButton &&
-        widget.onPressed != null &&
-        widget.child is Text &&
-        (widget.child! as Text).data == label,
-    description: 'an enabled "$label" button',
+  ///
+  /// ⚠️ **The label is looked for anywhere under the button, never as its
+  /// direct child.** This read `child is Text` until the button grew an
+  /// optional trailing mark and wrapped its label in a `Row` — after which
+  /// every wait here timed out against a button that was on screen the whole
+  /// time, and the gate stayed red across five merges. What the walk needs is
+  /// *an enabled button that says this*; how the button lays its label out is
+  /// the button's business.
+  Finder liveButton(String label) => find.ancestor(
+    of: find.text(label),
+    matching: find.byWidgetPredicate(
+      (widget) => widget is FilledButton && widget.onPressed != null,
+      description: 'an enabled "$label" button',
+    ),
   );
 
   /// Launches the app and skips the wake-up, leaving the caller on whatever
diff --git a/test/widget/core/widgets/primary_button_test.dart b/test/widget/core/widgets/primary_button_test.dart
new file mode 100644
index 00000000..7f4a5ac8
--- /dev/null
+++ b/test/widget/core/widgets/primary_button_test.dart
@@ -0,0 +1,72 @@
+import 'package:brew_path/app/app_theme.dart';
+import 'package:brew_path/core/icons/app_icon.dart';
+import 'package:brew_path/core/widgets/primary_button.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+/// The contract the smoke walk depends on: **an enabled button can be found
+/// by what it says.**
+///
+/// `integration_test/smoke_test.dart` drives onboarding by waiting for an
+/// enabled button carrying a label. It used to find one by reading the
+/// button's direct child as a `Text`; when the button grew an optional
+/// trailing mark and wrapped its label in a `Row`, every wait timed out
+/// against a button that was on screen, and main's smoke gate stayed red
+/// across five merges.
+///
+/// **The smoke job only runs on main**, so no pull request could catch that.
+/// This runs on every one. It asserts the relationship, not the layout: how
+/// the button arranges its label is the button's business, and this is free to
+/// keep passing while that changes.
+void main() {
+  /// The button that says [label], enabled — the shape the smoke walk uses.
+  Finder liveButton(String label) => find.ancestor(
+    of: find.text(label),
+    matching: find.byWidgetPredicate(
+      (widget) => widget is FilledButton && widget.onPressed != null,
+    ),
+  );
+
+  Future<void> pump(WidgetTester tester, Widget button) => tester.pumpWidget(
+    MaterialApp(
+      theme: AppTheme.cupping,
+      home: Scaffold(body: Center(child: button)),
+    ),
+  );
+
+  testWidgets('an enabled button is found by its label', (tester) async {
+    await pump(
+      tester,
+      PrimaryButton(label: 'Start learning', onPressed: () {}),
+    );
+
+    expect(liveButton('Start learning'), findsOneWidget);
+  });
+
+  testWidgets('a label beside a trailing mark is still found', (tester) async {
+    // The case that broke it: the mark is what put a `Row` between the button
+    // and its words.
+    await pump(
+      tester,
+      PrimaryButton(
+        label: 'Turn it over',
+        onPressed: () {},
+        trailingMark: AppIcon.chevron,
+      ),
+    );
+
+    expect(liveButton('Turn it over'), findsOneWidget);
+  });
+
+  testWidgets('a disabled button is not live', (tester) async {
+    // The distinction the walk exists to make: tapping a disabled button
+    // succeeds and does nothing, so waiting for one must not resolve.
+    await pump(
+      tester,
+      const PrimaryButton(label: 'Continue', onPressed: null),
+    );
+
+    expect(find.text('Continue'), findsOneWidget);
+    expect(liveButton('Continue'), findsNothing);
+  });
+}