Black box: the queries of the user's train worked out once a read, lights as the driver checks them

- The stations, the signals passed, the horn points, the couplings, the
  consists and the timetable progress of the user's train are kept until
  a read adds something; the views asked for them every frame, which on
  a long session with many trains took the window down. A read that adds
  nothing no longer counts as a change.
- The lights are checked against the lamps the vehicles at the ends have
  (written by the simulator from now on), as its driver checks them: Pc 1
  without the upper headlight, with the auxiliary lamps, Pc 5 with the
  rear-end signals. Only while the user drives: the autopilot's lights
  are its own.
- A train off the platform counts at both ends: its head past the stop
  point as well as its tail before the platform's end.
- A recording without the couplings keeps the timetable for any vehicle
  of the user.
- A signal passed at danger is ringed on the map only once it was.
- In the tapes window a black box opens on a click or Enter, not when
  the arrow keys go over it.
- The viewer's screenshot of a window not laid out saves nothing and
  still closes.

StarterNG.Tests/BlackBox/BlackBoxSignalsTests.cs

@@ -68,6 +68,62 @@ public class HeadCodeTests
         Assert.False(fault.TailWrong);
     }
 
+    private static Recording DriveWith(ushort head, ushort tail, ushort equippedHead, ushort equippedTail, byte movement = 1, byte driving = 1)
+    {
+        var f = new BlackBoxFile().Info();
+        for (double t = 0; t < 30; t += 0.5)
+            f.Cab(t, 1, 1000 + t * 10, 40, driving: driving, lightsHead: head, lightsTail: tail, movement: movement,
+                  equippedHead: equippedHead, equippedTail: equippedTail);
+        return BlackBoxReader.Read(f.End(30).Stream());
+    }
+
+    [Fact]
+    public void The_lamps_the_vehicles_have_are_read()
+    {
+        var sample = DriveWith(Pc1, Pc5, 0x1B5, 0x22).Cab[0];
+        Assert.Equal((Lights)0x1B5, sample.EquippedHead);
+        Assert.Equal((Lights)0x22, sample.EquippedTail);
+    }
+
+    [Theory]
+    // without the upper headlight Pc 1 is the two others
+    [InlineData(0x11, 0x11)]
+    // with auxiliary lamps, those and the upper headlight
+    [InlineData(0x184, 0x1B5)]
+    // a vehicle with no lamps for it: the rear-end signals
+    [InlineData(0x40, 0x40)]
+    public void Pc1_is_what_the_vehicle_can_show_of_it(ushort lit, ushort equipped)
+    {
+        var summary = DriveWith(lit, Pc5, equipped, Pc5).Summarize();
+        Assert.True(summary.LightsJudgedSeconds > 25);
+        Assert.Empty(summary.LightsFaults);
+    }
+
+    [Fact]
+    public void A_tail_with_the_rear_end_signals_only_shows_Pc5_with_them()
+    {
+        Assert.Empty(DriveWith(Pc1, 0x40, Pc1, 0x40).Summarize().LightsFaults);
+        var fault = Assert.Single(DriveWith(Pc1, 0x00, Pc1, 0x40).Summarize().LightsFaults);
+        Assert.False(fault.HeadWrong);
+        Assert.True(fault.TailWrong);
+    }
+
+    [Fact]
+    public void A_vehicle_with_all_the_lamps_is_to_light_all_three_for_Pc1()
+    {
+        var fault = Assert.Single(DriveWith(0x11, Pc5, 0x35, Pc5).Summarize().LightsFaults);
+        Assert.True(fault.HeadWrong);
+        Assert.Equal(HeadCode.Pc1, fault.HeadRequired);
+    }
+
+    [Fact]
+    public void The_lights_the_autopilot_sets_are_not_the_users()
+    {
+        var summary = DriveWith(Tb1, Tb1, Pc1, Pc5, driving: 2).Summarize();
+        Assert.Equal(0, summary.LightsJudgedSeconds);
+        Assert.Empty(summary.LightsFaults);
+    }
+
     [Fact]
     public void An_older_recording_tells_nothing_of_the_signals()
     {