Refactor (#94)

CliFx.Analyzers.Tests/SystemConsoleShouldBeAvoidedAnalyzerSpecs.cs

@@ -0,0 +1,108 @@
+using CliFx.Analyzers.Tests.Utils;
+using Microsoft.CodeAnalysis.Diagnostics;
+using Xunit;
+
+namespace CliFx.Analyzers.Tests
+{
+    public class SystemConsoleShouldBeAvoidedAnalyzerSpecs
+    {
+        private static DiagnosticAnalyzer Analyzer { get; } = new SystemConsoleShouldBeAvoidedAnalyzer();
+
+        [Fact]
+        public void Analyzer_reports_an_error_if_a_command_calls_a_method_on_SystemConsole()
+        {
+            // Arrange
+            // language=cs
+            const string code = @"
+[Command]
+public class MyCommand : ICommand
+{
+    public ValueTask ExecuteAsync(IConsole console)
+    {
+        Console.WriteLine(""Hello world"");
+        return default;
+    }
+}";
+
+            // Act & assert
+            Analyzer.Should().ProduceDiagnostics(code);
+        }
+
+        [Fact]
+        public void Analyzer_reports_an_error_if_a_command_accesses_a_property_on_SystemConsole()
+        {
+            // Arrange
+            // language=cs
+            const string code = @"
+[Command]
+public class MyCommand : ICommand
+{
+    public ValueTask ExecuteAsync(IConsole console)
+    {
+        Console.ForegroundColor = ConsoleColor.Black;
+        return default;
+    }
+}";
+            // Act & assert
+            Analyzer.Should().ProduceDiagnostics(code);
+        }
+
+        [Fact]
+        public void Analyzer_reports_an_error_if_a_command_calls_a_method_on_a_property_of_SystemConsole()
+        {
+            // Arrange
+            // language=cs
+            const string code = @"
+[Command]
+public class MyCommand : ICommand
+{
+    public ValueTask ExecuteAsync(IConsole console)
+    {
+        Console.Error.WriteLine(""Hello world"");
+        return default;
+    }
+}";
+
+            // Act & assert
+            Analyzer.Should().ProduceDiagnostics(code);
+        }
+
+        [Fact]
+        public void Analyzer_does_not_report_an_error_if_a_command_interacts_with_the_console_through_IConsole()
+        {
+            // Arrange
+            // language=cs
+            const string code = @"
+[Command]
+public class MyCommand : ICommand
+{
+    public ValueTask ExecuteAsync(IConsole console)
+    {
+        console.Output.WriteLine(""Hello world"");
+        return default;
+    }
+}";
+
+            // Act & assert
+            Analyzer.Should().NotProduceDiagnostics(code);
+        }
+
+        [Fact]
+        public void Analyzer_does_not_report_an_error_if_IConsole_is_not_available_in_the_current_method()
+        {
+            // Arrange
+            // language=cs
+            const string code = @"
+[Command]
+public class MyCommand : ICommand
+{
+    public void SomeOtherMethod() => Console.WriteLine(""Test"");
+
+    public ValueTask ExecuteAsync(IConsole console) => default;
+}";
+
+            // Act & assert
+            Analyzer.Should().NotProduceDiagnostics(code);
+        }
+    }
+}