Add last-lap exercise

Author: ErikSchierboom

exercises/practice/split-second-stopwatch/SplitSecondStopwatch.cs

@@ -6,7 +6,51 @@ public enum StopwatchState
     Stopped
 }
 
-public class SplitSecondStopwatch
+public class SplitSecondStopwatch(TimeProvider time)
 {
+    private List<TimeSpan> _currentLapSegments = new();
+    private DateTimeOffset _currentSegmentStart = DateTimeOffset.MinValue;
+    
     public StopwatchState State { get; private set; }
+
+    public List<TimeSpan> PreviousLaps { get; } = new();
+    
+    public TimeSpan CurrentLap => 
+        State == StopwatchState.Ready || State == StopwatchState.Stopped
+            ? TimeSpan.Zero
+            : _currentLapSegments.Aggregate(TimeSpan.Zero, (total, segment) => total + segment) + CurrentSegment;
+
+    private TimeSpan CurrentSegment => time.GetUtcNow() - _currentSegmentStart;
+
+    public void Start()
+    {
+        _currentSegmentStart = time.GetUtcNow();
+        State = StopwatchState.Running;
+    }
+
+    public void Stop()
+    {
+        if (State == StopwatchState.Ready)
+            return;
+        
+        PreviousLaps.Add(CurrentLap);
+        _currentSegmentStart = DateTimeOffset.MinValue;
+        State = StopwatchState.Stopped;
+    }
+
+    public void Split()
+    {
+        State = StopwatchState.Running;
+    }
+
+    public void Pause()
+    {
+        State = StopwatchState.Paused;
+    }
+
+    public void Reset()
+    {
+        Stop();
+        Start();
+    }
 }

exercises/practice/split-second-stopwatch/SplitSecondStopwatch.csproj

@@ -9,6 +9,7 @@
     <Using Include="Xunit" />
   </ItemGroup>
   <ItemGroup>
+    <PackageReference Include="Microsoft.Extensions.TimeProvider.Testing" Version="9.2.0" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
     <PackageReference Include="xunit.v3" Version="1.1.0" />
     <PackageReference Include="xunit.runner.visualstudio" Version="3.0.2" />

exercises/practice/split-second-stopwatch/SplitSecondStopwatchTests.cs

@@ -1,44 +1,151 @@
+using Microsoft.Extensions.Time.Testing;
+
 public class SplitSecondStopwatchTests
 {
     [Fact]
-    public void InitalStateIsReady()       
+    public void NewStopwatchIsInReadyState()       
     {
-        var stopwatch = new SplitSecondStopwatch();
+        var stopwatch = new SplitSecondStopwatch(new FakeTimeProvider());
         Assert.Equal(StopwatchState.Ready, stopwatch.State);
     }
+    
+    [Fact]
+    public void NewStopwatchHasNoPreviousLaps()       
+    {
+        var stopwatch = new SplitSecondStopwatch(new FakeTimeProvider());
+        Assert.Empty(stopwatch.PreviousLaps);
+    }
+    
+    [Fact]
+    public void NewStopwatchHasCurrentLapSetToZero()       
+    {
+        var stopwatch = new SplitSecondStopwatch(new FakeTimeProvider());
+        Assert.Equal(TimeSpan.Zero, stopwatch.CurrentLap);
+    }
 
     [Fact]
-    public void StartChangesStateToRunning()       
+    public void StartWhenStateIsReadyChangesStateToRunning()       
     {
-        var stopwatch = new SplitSecondStopwatch();
+        var stopwatch = new SplitSecondStopwatch(new FakeTimeProvider());
         stopwatch.Start();
         Assert.Equal(StopwatchState.Running, stopwatch.State);
     }
 
     [Fact]
-    public void PauseChangesStateToPaused()       
+    public void StartWhenStateIsStoppedChangesStateToRunning()       
+    {
+        var stopwatch = new SplitSecondStopwatch(new FakeTimeProvider());
+        stopwatch.Start();
+        stopwatch.Stop();
+        
+        stopwatch.Start();
+        
+        Assert.Equal(StopwatchState.Running, stopwatch.State);
+    }
+    
+    [Fact]
+    public void StartWhenStateIsPausedChangesStateToRunning()       
     {
-        var stopwatch = new SplitSecondStopwatch();
+        var stopwatch = new SplitSecondStopwatch(new FakeTimeProvider());
         stopwatch.Start();
         stopwatch.Pause();
-        Assert.Equal(StopwatchState.Paused, stopwatch.State);
+ 
+        stopwatch.Start();
+        
+        Assert.Equal(StopwatchState.Running, stopwatch.State);
     }
 
     [Fact]
-    public void SplitKeepsStateAsRunning()
+    public void StartWhenStateIsRunningDoesNotChangeState()       
     {
-        var stopwatch = new SplitSecondStopwatch();
+        var stopwatch = new SplitSecondStopwatch(new FakeTimeProvider());
         stopwatch.Start();
-        stopwatch.Split();
+        
+        stopwatch.Start();
+        
         Assert.Equal(StopwatchState.Running, stopwatch.State);
     }
+    
+    [Fact]
+    public void CurrentLapReturnsTimeElapsedSinceStart()       
+    {
+        var timeProvider = new FakeTimeProvider();
+        var stopwatch = new SplitSecondStopwatch(timeProvider);
+        stopwatch.Start();
+
+        var elapsed = TimeSpan.FromSeconds(5);
+        timeProvider.Advance(elapsed);
+        
+        Assert.Equal(elapsed, stopwatch.CurrentLap);
+    }
+
+    [Fact]
+    public void StopWhenStateIsReadyDoesNotChangeState()       
+    {
+        var stopwatch = new SplitSecondStopwatch(new FakeTimeProvider());
+        stopwatch.Stop();
+        Assert.Equal(StopwatchState.Ready, stopwatch.State);
+    }
 
     [Fact]
-    public void StopChangesStateToStop()       
+    public void StopWhenStateIsStoppedDoesNotChangeState()       
     {
-        var stopwatch = new SplitSecondStopwatch();
+        var stopwatch = new SplitSecondStopwatch(new FakeTimeProvider());
         stopwatch.Start();
         stopwatch.Stop();
+        
+        stopwatch.Stop();
+        
+        Assert.Equal(StopwatchState.Stopped, stopwatch.State);
+    }
+    
+    [Fact]
+    public void StopWhenStateIsPausedChangesStateToStopped()       
+    {
+        var stopwatch = new SplitSecondStopwatch(new FakeTimeProvider());
+        stopwatch.Start();
+        stopwatch.Pause();
+ 
+        stopwatch.Stop();
+        
         Assert.Equal(StopwatchState.Stopped, stopwatch.State);
     }
+
+    [Fact]
+    public void StopWhenStateIsRunningChangesStateToStopped()       
+    {
+        var stopwatch = new SplitSecondStopwatch(new FakeTimeProvider());
+        stopwatch.Start();
+        
+        stopwatch.Stop();
+        
+        Assert.Equal(StopwatchState.Stopped, stopwatch.State);
+    }
+
+    [Fact]
+    public void StopAddsCurrentLapToPreviousLaps()       
+    {
+        var timeProvider = new FakeTimeProvider();
+        var stopwatch = new SplitSecondStopwatch(timeProvider);
+        stopwatch.Start();
+
+        var lapTime = TimeSpan.FromSeconds(56);
+        timeProvider.Advance(lapTime);
+        
+        stopwatch.Stop();
+        
+        var lastLap = Assert.Single(stopwatch.PreviousLaps);
+        Assert.Equal(lapTime, lastLap);
+    }
+    
+    [Fact]
+    public void StopResetsCurrentLapToZero()       
+    {
+        var stopwatch = new SplitSecondStopwatch(new FakeTimeProvider());
+        stopwatch.Start();
+        
+        stopwatch.Stop();
+        
+        Assert.Equal(TimeSpan.Zero, stopwatch.CurrentLap);
+    }
 }