test(routing): pin queryParameter, which a report claimed was broken

test/routing/magic_router_query_parameter_test.dart

@@ -0,0 +1,144 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:magic/magic.dart';
+
+/// Tests for [MagicRouter.queryParameter] and [MagicRouter.queryParameters].
+///
+/// Written to settle a report rather than to add coverage. A consumer put a
+/// query parameter on a route, read it back through `queryParameter`, got
+/// null, and filed it against this package. The evidence turned out to be a
+/// misreading: the value they were looking at came from `dusk:get_routes`,
+/// whose `location` is `route.settings.name` off the Navigator (the declared
+/// path pattern) rather than anything this router exposes.
+///
+/// So these pin what the router actually promises, both ways a caller can put
+/// a query on a location: the `queryParameters` argument, and inline in the
+/// path string, which is the shape `MagicRoute.to('/?scale=5000')` produces
+/// and the one the report used.
+void main() {
+  setUpAll(() {
+    TestWidgetsFlutterBinding.ensureInitialized();
+  });
+
+  setUp(() {
+    MagicApp.reset();
+    Magic.flush();
+    TitleManager.reset();
+    MagicRouter.reset();
+  });
+
+  group('MagicRouter.queryParameter', () {
+    testWidgets('reads a parameter passed through queryParameters', (
+      tester,
+    ) async {
+      MagicRoute.page('/', () => const SizedBox()).name('home');
+
+      await tester.pumpWidget(
+        MaterialApp.router(routerConfig: MagicRouter.instance.routerConfig),
+      );
+      await tester.pumpAndSettle();
+
+      MagicRouter.instance.to('/', queryParameters: {'scale': '5000'});
+      await tester.pumpAndSettle();
+
+      expect(MagicRouter.instance.queryParameter('scale'), '5000');
+    });
+
+    testWidgets('reads a parameter written inline in the path', (tester) async {
+      MagicRoute.page('/', () => const SizedBox()).name('home');
+
+      await tester.pumpWidget(
+        MaterialApp.router(routerConfig: MagicRouter.instance.routerConfig),
+      );
+      await tester.pumpAndSettle();
+
+      MagicRouter.instance.to('/?scale=5000');
+      await tester.pumpAndSettle();
+
+      expect(MagicRouter.instance.queryParameter('scale'), '5000');
+    });
+
+    testWidgets('is null for a key the location does not carry', (
+      tester,
+    ) async {
+      MagicRoute.page('/', () => const SizedBox()).name('home');
+
+      await tester.pumpWidget(
+        MaterialApp.router(routerConfig: MagicRouter.instance.routerConfig),
+      );
+      await tester.pumpAndSettle();
+
+      MagicRouter.instance.to('/?scale=5000');
+      await tester.pumpAndSettle();
+
+      expect(MagicRouter.instance.queryParameter('missing'), isNull);
+    });
+
+    testWidgets('clears when a later navigation carries no query', (
+      tester,
+    ) async {
+      MagicRoute.page('/', () => const SizedBox()).name('home');
+      MagicRoute.page('/profile', () => const SizedBox()).name('profile');
+
+      await tester.pumpWidget(
+        MaterialApp.router(routerConfig: MagicRouter.instance.routerConfig),
+      );
+      await tester.pumpAndSettle();
+
+      MagicRouter.instance.to('/?scale=5000');
+      await tester.pumpAndSettle();
+      expect(MagicRouter.instance.queryParameter('scale'), '5000');
+
+      // The query belongs to the LOCATION, not to the session: navigating
+      // somewhere without one has to clear it rather than leave a stale value
+      // a caller would read as still current.
+      MagicRouter.instance.to('/profile');
+      await tester.pumpAndSettle();
+      expect(MagicRouter.instance.queryParameter('scale'), isNull);
+    });
+  });
+
+  group('MagicRouter.queryParameters', () {
+    testWidgets('exposes every parameter on the location', (tester) async {
+      MagicRoute.page('/', () => const SizedBox()).name('home');
+
+      await tester.pumpWidget(
+        MaterialApp.router(routerConfig: MagicRouter.instance.routerConfig),
+      );
+      await tester.pumpAndSettle();
+
+      MagicRouter.instance.to('/?scale=5000&width=1440');
+      await tester.pumpAndSettle();
+
+      expect(MagicRouter.instance.queryParameters, {
+        'scale': '5000',
+        'width': '1440',
+      });
+    });
+
+    test('is empty rather than null before any route resolves', () {
+      expect(MagicRouter.instance.queryParameters, isEmpty);
+    });
+  });
+
+  group('Request, which is how a consumer reaches these', () {
+    testWidgets('query and queryParams delegate to the router', (tester) async {
+      MagicRoute.page('/', () => const SizedBox()).name('home');
+
+      await tester.pumpWidget(
+        MaterialApp.router(routerConfig: MagicRouter.instance.routerConfig),
+      );
+      await tester.pumpAndSettle();
+
+      MagicRouter.instance.to('/?scale=5000&width=1440');
+      await tester.pumpAndSettle();
+
+      // One line each (`request.dart:72` and `:83`), so this is not really
+      // testing logic. It is testing that the facade an app reads through is
+      // wired to the accessor above, which is the pairing the original report
+      // was about and the one nothing covered.
+      expect(Request.query('scale'), '5000');
+      expect(Request.queryParams, {'scale': '5000', 'width': '1440'});
+    });
+  });
+}