Fixes #4374 - Nukes all (?) legacy Driver and Application stuff; revamps tests (#4376)

Tests/UnitTests/Drivers/DriverTests.cs

@@ -0,0 +1,63 @@
+using System.Text;
+using UnitTests.ViewsTests;
+using Xunit.Abstractions;
+
+namespace UnitTests.DriverTests;
+
+public class DriverTests (ITestOutputHelper output)
+{
+    private readonly ITestOutputHelper _output = output;
+
+
+    [Theory]
+    [InlineData ("fake")]
+    [InlineData ("windows")]
+    [InlineData ("dotnet")]
+    [InlineData ("unix")]
+    public void All_Drivers_Init_Shutdown_Cross_Platform (string driverName = null)
+    {
+        Application.Init (null, driverName: driverName);
+        Application.Shutdown ();
+    }
+
+    [Theory]
+    [InlineData ("fake")]
+    [InlineData ("windows")]
+    [InlineData ("dotnet")]
+    [InlineData ("unix")]
+    public void All_Drivers_Run_Cross_Platform (string driverName = null)
+    {
+        Application.Init (null, driverName: driverName);
+        Application.StopAfterFirstIteration = true;
+        Application.Run ().Dispose ();
+        Application.Shutdown ();
+    }
+
+    [Theory]
+    [InlineData ("fake")]
+    [InlineData ("windows")]
+    [InlineData ("dotnet")]
+    [InlineData ("unix")]
+    public void All_Drivers_LayoutAndDraw_Cross_Platform (string driverName = null)
+    {
+        Application.Init (null, driverName: driverName);
+        Application.StopAfterFirstIteration = true;
+        Application.Run<TestTop> ().Dispose ();
+
+        DriverAssert.AssertDriverContentsWithFrameAre (expectedLook: driverName!, _output);
+
+        Application.Shutdown ();
+
+    }
+}
+
+public class TestTop : Toplevel
+{
+    /// <inheritdoc />
+    public override void BeginInit ()
+    {
+        Text = Driver!.GetName ()!;
+        BorderStyle = LineStyle.None;
+        base.BeginInit ();
+    }
+}