Refactor options validators and add tests

DiscordTranslationBot.Tests/Configuration/DiscordOptionsValidatorTests.cs

@@ -0,0 +1,38 @@
+using DiscordTranslationBot.Configuration;
+using FluentValidation.TestHelper;
+
+namespace DiscordTranslationBot.Tests.Configuration;
+
+public sealed class DiscordOptionsValidatorTests
+{
+    private readonly DiscordOptionsValidator _sut = new();
+
+    [Fact]
+    public void Valid_Options_ValidatesWithoutErrors()
+    {
+        // Arrange
+        var options = new DiscordOptions { BotToken = "token" };
+
+        // Act
+        var result = _sut.TestValidate(options);
+
+        // Assert
+        result.ShouldNotHaveAnyValidationErrors();
+    }
+
+    [Theory]
+    [InlineData(null)]
+    [InlineData("")]
+    [InlineData(" ")]
+    public void Invalid_BotToken_HasValidationErrors(string? botToken)
+    {
+        // Arrange
+        var options = new DiscordOptions { BotToken = botToken! };
+
+        // Act
+        var result = _sut.TestValidate(options);
+
+        // Assert
+        result.ShouldHaveValidationErrorFor(x => x.BotToken).Only();
+    }
+}

DiscordTranslationBot.Tests/Configuration/TranslationProviders/TranslationProvidersOptionsValidatorTests.cs

@@ -0,0 +1,61 @@
+using DiscordTranslationBot.Configuration.TranslationProviders;
+using FluentValidation.TestHelper;
+
+namespace DiscordTranslationBot.Tests.Configuration.TranslationProviders;
+
+public sealed class TranslationProvidersOptionsValidatorTests
+{
+    private readonly TranslationProvidersOptionsValidator _sut = new();
+
+    [Fact]
+    public void Valid_Options_ValidatesWithoutErrors()
+    {
+        // Arrange
+        var options = new TranslationProvidersOptions
+        {
+            AzureTranslator = new AzureTranslatorOptions
+            {
+                Enabled = true,
+                ApiUrl = new Uri("http://localhost", UriKind.Absolute),
+                Region = "westus",
+                SecretKey = "secret"
+            },
+            LibreTranslate = new LibreTranslateOptions { Enabled = false }
+        };
+
+        // Act
+        var result = _sut.TestValidate(options);
+
+        // Assert
+        result.ShouldNotHaveAnyValidationErrors();
+    }
+
+    [Theory]
+    [InlineData(null)]
+    [InlineData("")]
+    [InlineData(" ")]
+    public void Invalid_ProviderOptions_HasValidationErrors(string? stringValue)
+    {
+        // Arrange
+        var options = new TranslationProvidersOptions
+        {
+            AzureTranslator = new AzureTranslatorOptions
+            {
+                Enabled = true,
+                ApiUrl = null,
+                Region = stringValue,
+                SecretKey = stringValue
+            },
+            LibreTranslate = new LibreTranslateOptions { Enabled = true, ApiUrl = null }
+        };
+
+        // Act
+        var result = _sut.TestValidate(options);
+
+        // Assert
+        result.ShouldHaveValidationErrorFor(x => x.AzureTranslator.ApiUrl);
+        result.ShouldHaveValidationErrorFor(x => x.AzureTranslator.Region);
+        result.ShouldHaveValidationErrorFor(x => x.AzureTranslator.SecretKey);
+        result.ShouldHaveValidationErrorFor(x => x.LibreTranslate.ApiUrl);
+    }
+}

DiscordTranslationBot/Configuration/TranslationProviders/AzureTranslatorOptions.cs

@@ -1,15 +1,12 @@
-namespace DiscordTranslationBot.Configuration.TranslationProviders;
+using FluentValidation;
+
+namespace DiscordTranslationBot.Configuration.TranslationProviders;
 
 /// <summary>
 /// Options for the Azure Translator provider.
 /// </summary>
 public sealed class AzureTranslatorOptions : TranslationProviderOptionsBase
 {
-    /// <summary>
-    /// The API URL for Azure Translator.
-    /// </summary>
-    public Uri? ApiUrl { get; init; }
-
     /// <summary>
     /// The secret key for the Azure Translator API.
     /// </summary>
@@ -20,3 +17,26 @@ public sealed class AzureTranslatorOptions : TranslationProviderOptionsBase
     /// </summary>
     public string? Region { get; init; }
 }
+
+/// <summary>
+/// Validator for <see cref="AzureTranslatorOptions" />.
+/// </summary>
+public sealed class AzureTranslatorOptionsValidator : AbstractValidator<AzureTranslatorOptions>
+{
+    /// <summary>
+    /// Initializes validation rules.
+    /// </summary>
+    public AzureTranslatorOptionsValidator()
+    {
+        Include(new TranslationProviderOptionsBaseValidator());
+
+        When(
+            x => x.Enabled,
+            () =>
+            {
+                RuleFor(x => x.SecretKey).NotEmpty();
+                RuleFor(x => x.Region).NotEmpty();
+            }
+        );
+    }
+}

DiscordTranslationBot/Configuration/TranslationProviders/LibreTranslateOptions.cs

@@ -1,12 +1,22 @@
-namespace DiscordTranslationBot.Configuration.TranslationProviders;
+using FluentValidation;
+
+namespace DiscordTranslationBot.Configuration.TranslationProviders;
 
 /// <summary>
 /// Options for the LibreTranslate provider.
 /// </summary>
-public sealed class LibreTranslateOptions : TranslationProviderOptionsBase
+public sealed class LibreTranslateOptions : TranslationProviderOptionsBase { }
+
+/// <summary>
+/// Validator for <see cref="LibreTranslateOptions" />.
+/// </summary>
+public sealed class LibreTranslateOptionsValidator : AbstractValidator<LibreTranslateOptions>
 {
     /// <summary>
-    /// The API URL for LibreTranslate.
+    /// Initializes validation rules.
     /// </summary>
-    public Uri? ApiUrl { get; init; }
+    public LibreTranslateOptionsValidator()
+    {
+        Include(new TranslationProviderOptionsBaseValidator());
+    }
 }

DiscordTranslationBot/Configuration/TranslationProviders/TranslationProviderOptionsBase.cs

@@ -1,4 +1,6 @@
-namespace DiscordTranslationBot.Configuration.TranslationProviders;
+using FluentValidation;
+
+namespace DiscordTranslationBot.Configuration.TranslationProviders;
 
 /// <summary>
 /// Base class for a translation provider's options.
@@ -9,4 +11,23 @@ public abstract class TranslationProviderOptionsBase
     /// Flag indicating whether this provider is enabled.
     /// </summary>
     public bool Enabled { get; init; }
+
+    /// <summary>
+    /// The API URL for Azure Translator.
+    /// </summary>
+    public Uri? ApiUrl { get; init; }
+}
+
+/// <summary>
+/// Validator for <see cref="TranslationProviderOptionsBase" />.
+/// </summary>
+public sealed class TranslationProviderOptionsBaseValidator : AbstractValidator<TranslationProviderOptionsBase>
+{
+    /// <summary>
+    /// Initializes validation rules.
+    /// </summary>
+    public TranslationProviderOptionsBaseValidator()
+    {
+        When(x => x.Enabled, () => RuleFor(x => x.ApiUrl).NotNull());
+    }
 }

DiscordTranslationBot/Configuration/TranslationProviders/TranslationProvidersOptions.cs

@@ -29,22 +29,11 @@ public sealed class TranslationProvidersOptions
 public sealed class TranslationProvidersOptionsValidator : AbstractValidator<TranslationProvidersOptions>
 {
     /// <summary>
-    /// Initializes a new instance of the <see cref="TranslationProvidersOptionsValidator" /> class.
+    /// Initializes validation rules.
     /// </summary>
     public TranslationProvidersOptionsValidator()
     {
-        // Validate Azure Translator options.
-        When(
-            x => x.AzureTranslator.Enabled,
-            () =>
-            {
-                RuleFor(x => x.AzureTranslator.ApiUrl).NotNull();
-                RuleFor(x => x.AzureTranslator.SecretKey).NotEmpty();
-                RuleFor(x => x.AzureTranslator.Region).NotEmpty();
-            }
-        );
-
-        // Validate Libre Translate options.
-        When(x => x.LibreTranslate.Enabled, () => RuleFor(x => x.LibreTranslate.ApiUrl).NotNull());
+        RuleFor(x => x.AzureTranslator).SetValidator(new AzureTranslatorOptionsValidator());
+        RuleFor(x => x.LibreTranslate).SetValidator(new LibreTranslateOptionsValidator());
     }
 }

DiscordTranslationBot/Extensions/ServiceCollectionExtensions.cs

@@ -26,7 +26,6 @@ IConfigurationSection configurationSection
         where TValidator : class, IValidator<TOptions>
     {
         services.AddTransient<IValidator<TOptions>, TValidator>();
-
         services.AddOptions<TOptions>().Bind(configurationSection).ValidateWithFluentValidation().ValidateOnStart();
     }