Add support for required options

src/Tests/Spectre.Console.Cli.Tests/Data/Settings/RequiredOptionsSettings.cs

@@ -0,0 +1,7 @@
+namespace Spectre.Console.Tests.Data;
+
+public class RequiredOptionsSettings : CommandSettings
+{
+    [CommandOption("--foo <VALUE>", true)]
+    public string Foo { get; set; }
+}

src/Tests/Spectre.Console.Cli.Tests/Unit/CommandAppTests.Options.cs

@@ -0,0 +1,27 @@
+namespace Spectre.Console.Tests.Unit.Cli;
+
+public sealed partial class CommandAppTests
+{
+    public sealed class Options
+    {
+        [Fact]
+        public void Should_Throw_If_Required_Option_Is_Missing()
+        {
+            // Given
+            var fixture = new CommandAppTester();
+            fixture.Configure(config =>
+            {
+                config.AddCommand<GenericCommand<RequiredOptionsSettings>>("test");
+                config.PropagateExceptions();
+            });
+
+            // When
+            var result = Record.Exception(() => fixture.Run("test"));
+
+            // Then
+            result.ShouldBeOfType<CommandRuntimeException>()
+                .And(ex =>
+                    ex.Message.ShouldBe("Command 'test' is missing required argument 'foo'."));
+        }
+    }
+}

src/Tests/Spectre.Console.Cli.Tests/Unit/CommandAppTests.Sensitivity.cs

@@ -1,6 +1,6 @@
 namespace Spectre.Console.Tests.Unit.Cli;
 
-public sealed partial class CommandApptests
+public sealed partial class CommandAppTests
 {
     [Fact]
     public void Should_Treat_Commands_As_Case_Sensitive_If_Specified()