Refactor (#94)

CliFx.Analyzers.Tests/ParameterMustHaveUniqueOrderAnalyzerSpecs.cs

@@ -0,0 +1,73 @@
+using CliFx.Analyzers.Tests.Utils;
+using Microsoft.CodeAnalysis.Diagnostics;
+using Xunit;
+
+namespace CliFx.Analyzers.Tests
+{
+    public class ParameterMustHaveUniqueOrderAnalyzerSpecs
+    {
+        private static DiagnosticAnalyzer Analyzer { get; } = new ParameterMustHaveUniqueOrderAnalyzer();
+
+        [Fact]
+        public void Analyzer_reports_an_error_if_a_parameter_has_the_same_order_as_another_parameter()
+        {
+            // Arrange
+            // language=cs
+            const string code = @"
+[Command]
+public class MyCommand : ICommand
+{
+    [CommandParameter(0)]
+    public string Foo { get; set; }
+    
+    [CommandParameter(0)]
+    public string Bar { get; set; }
+
+    public ValueTask ExecuteAsync(IConsole console) => default;
+}";
+
+            // Act & assert
+            Analyzer.Should().ProduceDiagnostics(code);
+        }
+
+        [Fact]
+        public void Analyzer_does_not_report_an_error_if_a_parameter_has_unique_order()
+        {
+            // Arrange
+            // language=cs
+            const string code = @"
+[Command]
+public class MyCommand : ICommand
+{
+    [CommandParameter(0)]
+    public string Foo { get; set; }
+    
+    [CommandParameter(1)]
+    public string Bar { get; set; }
+
+    public ValueTask ExecuteAsync(IConsole console) => default;
+}";
+
+            // Act & assert
+            Analyzer.Should().NotProduceDiagnostics(code);
+        }
+
+        [Fact]
+        public void Analyzer_does_not_report_an_error_on_a_property_that_is_not_a_parameter()
+        {
+            // Arrange
+            // language=cs
+            const string code = @"
+[Command]
+public class MyCommand : ICommand
+{
+    public string Foo { get; set; }
+
+    public ValueTask ExecuteAsync(IConsole console) => default;
+}";
+
+            // Act & assert
+            Analyzer.Should().NotProduceDiagnostics(code);
+        }
+    }
+}