Cover history_screen.dart to 100%

Add an exercise drill-down test (dropdown select -> streak stats card,
weight chart, exercise calendar nav, session tiles with warmup/reps
variants) and a same-date test for the chart painter's tRange==0 branch.
coverage:ignore the _load exercise-state branch (unreachable — selection
goes through _pickExercise, not _load).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UWkAKQ48Jhg5iSPkzh8NsH

stronglift_replacement/workout_app/lib/screens/history_screen.dart

@@ -51,7 +51,12 @@ class _HistoryScreenState extends State<HistoryScreen> {
     }
     ExerciseState? state;
     if (_selected != _kTotal) {
+      // Unreachable in practice: _load only runs from initState, where
+      // _selected is still _kTotal; exercise selection goes through
+      // _pickExercise, which loads its own state.
+      // coverage:ignore-start
       state = await StorageService.instance.getExerciseState(_selected);
+      // coverage:ignore-end
     }
     if (mounted) {
       setState(() {

stronglift_replacement/workout_app/test/screens/history_screen_test.dart

@@ -3,6 +3,7 @@ import 'dart:convert';
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:sqflite_common_ffi/sqflite_ffi.dart';
+import 'package:workout_app/models/workout_plan.dart';
 import 'package:workout_app/screens/history_screen.dart';
 import 'package:workout_app/services/storage_service.dart';
 
@@ -153,4 +154,126 @@ void main() {
     await _pump(tester, _wrap());
     expect(find.byType(HistoryScreen), findsOneWidget);
   });
+
+  // JSON for one session containing [name] at [weight].
+  String _exerciseSessionJson(
+    String name,
+    double weight, {
+    required bool ok,
+    required bool warmup,
+    required bool withSets,
+  }) {
+    return jsonEncode({
+      'exercises': [
+        {
+          'name': name,
+          'targetSets': 3,
+          'targetReps': 5,
+          'targetWeight': weight,
+          'warmupDone': warmup,
+          'succeeded': ok,
+          'sets': withSets
+              ? [
+                  {
+                    'targetReps': 5,
+                    'doneReps': 5,
+                    'weight': weight,
+                    'succeeded': true,
+                  },
+                  {
+                    'targetReps': 5,
+                    'doneReps': 4,
+                    'weight': weight,
+                    'succeeded': false,
+                  },
+                ]
+              : <Map<String, dynamic>>[],
+        },
+      ],
+    });
+  }
+
+  testWidgets('selecting an exercise shows the drill-down view', (tester) async {
+    // Use a real progression-tracked exercise so getExerciseState is non-null
+    // and the streak stats card renders. Three distinct weights on three dates
+    // give the weight chart >= 2 points with a real range (painter fully runs).
+    final name = workoutA.first.name;
+    await _seed(
+      tester,
+      _exerciseSessionJson(name, 20, ok: true, warmup: true, withSets: true),
+      date: '2024-06-01',
+    );
+    await _seed(
+      tester,
+      _exerciseSessionJson(name, 22.5, ok: false, warmup: false, withSets: false),
+      date: '2024-06-08',
+      succeeded: false,
+    );
+    await _seed(
+      tester,
+      _exerciseSessionJson(name, 25, ok: true, warmup: true, withSets: true),
+      date: '2024-06-15',
+    );
+
+    await _pump(tester, _wrap());
+
+    // Open the dropdown and pick the exercise; _pickExercise awaits a DB read,
+    // and the menu open/close animation runs on real timers under runAsync, so
+    // drive the whole interaction on the real loop.
+    await tester.runAsync(() async {
+      await tester.tap(find.byType(DropdownButton<String>));
+      await Future<void>.delayed(const Duration(milliseconds: 400));
+      await tester.pump();
+      await tester.tap(find.text(name).last);
+      await Future<void>.delayed(const Duration(milliseconds: 400));
+      await tester.pump();
+    });
+    await tester.pump();
+    await tester.pump(const Duration(milliseconds: 300));
+
+    // Exercise view rendered: chart + streak stats card near the top.
+    expect(find.text('WEIGHT OVER TIME'), findsOneWidget);
+    expect(find.textContaining('more to'), findsWidgets);
+
+    // Exercise-view calendar month nav (covers its onPrev/onNext closures).
+    await tester.tap(find.byIcon(Icons.chevron_right).first);
+    await tester.pump();
+    await tester.tap(find.byIcon(Icons.chevron_left).first);
+    await tester.pump();
+
+    // The session list + name label sit below the fold; scroll to build them.
+    await tester.scrollUntilVisible(
+      find.text(name.toUpperCase()),
+      300,
+      scrollable: find.byType(Scrollable).first,
+    );
+    expect(find.text(name.toUpperCase()), findsOneWidget);
+    // Session tiles: warmup marker and reps summary both present.
+    expect(find.textContaining('warmup'), findsWidgets);
+    expect(find.textContaining('reps:'), findsWidgets);
+  });
+
+  testWidgets('chart handles two points on the same date (tRange == 0)',
+      (tester) async {
+    // Two sessions on the SAME date give the total chart two points that share
+    // a timestamp, exercising the painter's tRange == 0 (centre-x) branch.
+    String vol(double w) => jsonEncode({
+          'exercises': [
+            {
+              'name': 'Squat',
+              'targetSets': 3,
+              'targetReps': 5,
+              'targetWeight': w,
+              'warmupDone': false,
+              'succeeded': true,
+              'sets': <Map<String, dynamic>>[],
+            },
+          ],
+        });
+    await _seed(tester, vol(20), date: '2024-06-01');
+    await _seed(tester, vol(40), date: '2024-06-01');
+    await _pump(tester, _wrap());
+    expect(find.byType(HistoryScreen), findsOneWidget);
+    expect(find.text('WEIGHT OVER TIME').evaluate(), isEmpty); // total view
+  });
 }