File: ValidationMessageTagHelperTest.cs
Web Access
Project: src\src\Mvc\Mvc.TagHelpers\test\Microsoft.AspNetCore.Mvc.TagHelpers.Test.csproj (Microsoft.AspNetCore.Mvc.TagHelpers.Test)
// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using Microsoft.AspNetCore.Html;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc.Abstractions;
using Microsoft.AspNetCore.Mvc.ModelBinding;
using Microsoft.AspNetCore.Mvc.Rendering;
using Microsoft.AspNetCore.Mvc.ViewEngines;
using Microsoft.AspNetCore.Mvc.ViewFeatures;
using Microsoft.AspNetCore.Razor.TagHelpers;
using Microsoft.AspNetCore.Routing;
using Microsoft.AspNetCore.InternalTesting;
using Moq;
 
namespace Microsoft.AspNetCore.Mvc.TagHelpers;
 
public class ValidationMessageTagHelperTest
{
    [Fact]
    public async Task ProcessAsync_GeneratesExpectedOutput()
    {
        // Arrange
        var expectedTagName = "not-span";
        var metadataProvider = new TestModelMetadataProvider();
        var modelExpression = CreateModelExpression("Name");
        var htmlGenerator = new TestableHtmlGenerator(metadataProvider);
 
        var validationMessageTagHelper = new ValidationMessageTagHelper(htmlGenerator)
        {
            For = modelExpression
        };
 
        var expectedPreContent = "original pre-content";
        var expectedContent = "original content";
        var expectedPostContent = "original post-content";
 
        var tagHelperContext = new TagHelperContext(
            tagName: "not-span",
            allAttributes: new TagHelperAttributeList
            {
                    { "id", "myvalidationmessage" },
                    { "for", modelExpression },
            },
            items: new Dictionary<object, object>(),
            uniqueId: "test");
        var output = new TagHelperOutput(
            expectedTagName,
            attributes: new TagHelperAttributeList
            {
                    { "id", "myvalidationmessage" }
            },
            getChildContentAsync: (useCachedResult, encoder) =>
            {
                var tagHelperContent = new DefaultTagHelperContent();
                tagHelperContent.SetContent("Something");
                return Task.FromResult<TagHelperContent>(tagHelperContent);
            });
        output.PreContent.SetContent(expectedPreContent);
        output.Content.SetContent(expectedContent);
        output.PostContent.SetContent(expectedPostContent);
 
        var viewContext = TestableHtmlGenerator.GetViewContext(
            model: null,
            htmlGenerator: htmlGenerator,
            metadataProvider: metadataProvider);
        validationMessageTagHelper.ViewContext = viewContext;
 
        // Act
        await validationMessageTagHelper.ProcessAsync(tagHelperContext, output);
 
        // Assert
        Assert.Equal(4, output.Attributes.Count);
        var attribute = Assert.Single(output.Attributes, attr => attr.Name.Equals("id"));
        Assert.Equal("myvalidationmessage", attribute.Value);
        attribute = Assert.Single(output.Attributes, attr => attr.Name.Equals("class"));
        Assert.Equal("field-validation-valid", attribute.Value);
        attribute = Assert.Single(output.Attributes, attr => attr.Name.Equals("data-valmsg-for"));
        Assert.Equal("Name", attribute.Value);
        attribute = Assert.Single(output.Attributes, attr => attr.Name.Equals("data-valmsg-replace"));
        Assert.Equal("true", attribute.Value);
        Assert.Equal(expectedPreContent, output.PreContent.GetContent());
        Assert.Equal(expectedContent, output.Content.GetContent());
        Assert.Equal(expectedPostContent, output.PostContent.GetContent());
        Assert.Equal(expectedTagName, output.TagName);
    }
 
    [Fact]
    public async Task ProcessAsync_WithEmptyNameFor_Throws()
    {
        // Arrange
        var expectedTagName = "span";
        var expectedMessage = "The name of an HTML field cannot be null or empty. Instead use methods " +
            "Microsoft.AspNetCore.Mvc.Rendering.IHtmlHelper.Editor or Microsoft.AspNetCore.Mvc.Rendering." +
            "IHtmlHelper`1.EditorFor with a non-empty htmlFieldName argument value.";
 
        var metadataProvider = new EmptyModelMetadataProvider();
        var modelExpression = CreateModelExpression(string.Empty);
        var htmlGenerator = new TestableHtmlGenerator(metadataProvider);
        var viewContext = TestableHtmlGenerator.GetViewContext(
            model: null,
            htmlGenerator: htmlGenerator,
            metadataProvider: metadataProvider);
 
        var validationMessageTagHelper = new ValidationMessageTagHelper(htmlGenerator)
        {
            For = modelExpression,
            ViewContext = viewContext,
        };
 
        var tagHelperContext = new TagHelperContext(
            expectedTagName,
            new TagHelperAttributeList
            {
                    { "for", modelExpression },
            },
            new Dictionary<object, object>(),
            "test");
 
        var output = new TagHelperOutput(
            expectedTagName,
            new TagHelperAttributeList(),
            (_, __) => Task.FromResult<TagHelperContent>(new DefaultTagHelperContent()));
 
        // Act & Assert
        await ExceptionAssert.ThrowsArgumentAsync(
            () => validationMessageTagHelper.ProcessAsync(tagHelperContext, output),
            paramName: "expression",
            exceptionMessage: expectedMessage);
    }
 
    [Fact]
    public async Task ProcessAsync_GeneratesExpectedOutput_WithEmptyNameFor_WithValidationFor()
    {
        // Arrange
        var expectedAttributeValue = "-expression-";
        var expectedTagName = "span";
 
        var metadataProvider = new EmptyModelMetadataProvider();
        var modelExpression = CreateModelExpression(string.Empty);
        var htmlGenerator = new TestableHtmlGenerator(metadataProvider);
        var viewContext = TestableHtmlGenerator.GetViewContext(
            model: null,
            htmlGenerator: htmlGenerator,
            metadataProvider: metadataProvider);
 
        var validationMessageTagHelper = new ValidationMessageTagHelper(htmlGenerator)
        {
            For = modelExpression,
            ViewContext = viewContext,
        };
 
        var tagHelperContext = new TagHelperContext(
            expectedTagName,
            new TagHelperAttributeList
            {
                    { "for", modelExpression },
            },
            new Dictionary<object, object>(),
            "test");
 
        var output = new TagHelperOutput(
            expectedTagName,
            new TagHelperAttributeList
            {
                    { "data-valmsg-for", expectedAttributeValue },
            },
            (_, __) => Task.FromResult<TagHelperContent>(new DefaultTagHelperContent()));
 
        validationMessageTagHelper.ViewContext = viewContext;
 
        // Act
        await validationMessageTagHelper.ProcessAsync(tagHelperContext, output);
 
        // Assert
        Assert.Equal(expectedTagName, output.TagName);
        Assert.Collection(output.Attributes,
            attribute =>
            {
                Assert.Equal("data-valmsg-for", attribute.Name);
                Assert.Equal(expectedAttributeValue, attribute.Value);
            },
            attribute =>
            {
                Assert.Equal("class", attribute.Name);
                Assert.Equal("field-validation-valid", attribute.Value);
            },
            attribute =>
            {
                Assert.Equal("data-valmsg-replace", attribute.Name);
                Assert.Equal("true", attribute.Value);
            });
    }
 
    [Fact]
    public async Task ProcessAsync_PassesValidationForThrough_EvenIfNullFor()
    {
        // Arrange
        var expectedAttributeValue = "-expression-";
        var expectedTagName = "span";
 
        // Generator is not used in this scenario.
        var generator = new Mock<IHtmlGenerator>(MockBehavior.Strict);
        var validationMessageTagHelper = new ValidationMessageTagHelper(generator.Object)
        {
            ViewContext = CreateViewContext(),
        };
 
        var tagHelperContext = new TagHelperContext(
            expectedTagName,
            new TagHelperAttributeList(),
            new Dictionary<object, object>(),
            "test");
 
        var output = new TagHelperOutput(
            expectedTagName,
            new TagHelperAttributeList
            {
                    { "data-valmsg-for", expectedAttributeValue },
            },
            (_, __) => Task.FromResult<TagHelperContent>(new DefaultTagHelperContent()));
 
        // Act
        await validationMessageTagHelper.ProcessAsync(tagHelperContext, output);
 
        // Assert
        Assert.Equal(expectedTagName, output.TagName);
        var attribute = Assert.Single(output.Attributes);
        Assert.Equal("data-valmsg-for", attribute.Name);
        Assert.Equal(expectedAttributeValue, attribute.Value);
    }
 
    [Fact]
    public async Task ProcessAsync_CallsIntoGenerateValidationMessageWithExpectedParameters()
    {
        // Arrange
        var expectedViewContext = CreateViewContext();
        var modelExpression = CreateModelExpression("Hello");
        var generator = new Mock<IHtmlGenerator>();
        generator
            .Setup(mock => mock.GenerateValidationMessage(
                expectedViewContext,
                modelExpression.ModelExplorer,
                modelExpression.Name,
                null,
                null,
                null))
            .Returns(new TagBuilder("span"))
            .Verifiable();
 
        var validationMessageTagHelper = new ValidationMessageTagHelper(generator.Object)
        {
            For = modelExpression,
        };
        var expectedPreContent = "original pre-content";
        var expectedContent = "original content";
        var expectedPostContent = "original post-content";
        var context = new TagHelperContext(
            tagName: "span",
            allAttributes: new TagHelperAttributeList(
                Enumerable.Empty<TagHelperAttribute>()),
            items: new Dictionary<object, object>(),
            uniqueId: "test");
        var output = new TagHelperOutput(
            "span",
            attributes: new TagHelperAttributeList(),
            getChildContentAsync: (useCachedResult, encoder) =>
            {
                var tagHelperContent = new DefaultTagHelperContent();
                tagHelperContent.SetContent("Something");
                return Task.FromResult<TagHelperContent>(tagHelperContent);
            });
        output.PreContent.SetContent(expectedPreContent);
        output.Content.SetContent(expectedContent);
        output.PostContent.SetContent(expectedPostContent);
 
        validationMessageTagHelper.ViewContext = expectedViewContext;
 
        // Act & Assert
        await validationMessageTagHelper.ProcessAsync(context, output);
 
        generator.Verify();
        Assert.Equal("span", output.TagName);
        Assert.Empty(output.Attributes);
        Assert.Equal(expectedPreContent, output.PreContent.GetContent());
        Assert.Equal(expectedContent, output.Content.GetContent());
        Assert.Equal(expectedPostContent, output.PostContent.GetContent());
    }
 
    [Theory]
    [InlineData("Content of validation message", "Some Content", "Some Content")]
    [InlineData("\r\n  \r\n", "\r\n Something Else \r\n", "\r\n Something Else \r\n")]
    [InlineData("\r\n  \r\n", "Some Content", "Some Content")]
    public async Task ProcessAsync_DoesNotOverrideOutputContent(
        string childContent,
        string outputContent,
        string expectedOutputContent)
    {
        // Arrange
        var tagBuilder = new TagBuilder("span2");
        tagBuilder.InnerHtml.SetHtmlContent("New HTML");
        tagBuilder.Attributes.Add("data-foo", "bar");
        tagBuilder.Attributes.Add("data-hello", "world");
 
        var generator = new Mock<IHtmlGenerator>(MockBehavior.Strict);
        var setup = generator
            .Setup(mock => mock.GenerateValidationMessage(
                It.IsAny<ViewContext>(),
                It.IsAny<ModelExplorer>(),
                It.IsAny<string>(),
                It.IsAny<string>(),
                It.IsAny<string>(),
                It.IsAny<object>()))
            .Returns(tagBuilder);
 
        var validationMessageTagHelper = new ValidationMessageTagHelper(generator.Object)
        {
            For = CreateModelExpression("Hello")
        };
        var output = new TagHelperOutput(
            "span",
            attributes: new TagHelperAttributeList(),
            getChildContentAsync: (useCachedResult, encoder) =>
            {
                var tagHelperContent = new DefaultTagHelperContent();
                tagHelperContent.AppendHtml(childContent);
                return Task.FromResult<TagHelperContent>(tagHelperContent);
            });
        output.Content.AppendHtml(outputContent);
 
        var context = new TagHelperContext(
            tagName: "span",
            allAttributes: new TagHelperAttributeList(
                Enumerable.Empty<TagHelperAttribute>()),
            items: new Dictionary<object, object>(),
            uniqueId: "test");
 
        var viewContext = CreateViewContext();
        validationMessageTagHelper.ViewContext = viewContext;
 
        // Act
        await validationMessageTagHelper.ProcessAsync(context, output);
 
        // Assert
        Assert.Equal("span", output.TagName);
        Assert.Equal(2, output.Attributes.Count);
        var attribute = Assert.Single(output.Attributes, attr => attr.Name.Equals("data-foo"));
        Assert.Equal("bar", attribute.Value);
        attribute = Assert.Single(output.Attributes, attr => attr.Name.Equals("data-hello"));
        Assert.Equal("world", attribute.Value);
        Assert.Equal(expectedOutputContent, output.Content.GetContent());
    }
 
    [Theory]
    [InlineData("Content of validation message", "Content of validation message", "New HTML")]
    [InlineData("\r\n  \r\n", null, "New HTML")]
    public async Task ProcessAsync_MergesTagBuilderFromGenerateValidationMessage(
        string childContent,
        string expectedMessage,
        string expectedOutputContent)
    {
        // Arrange
        var tagBuilder = new TagBuilder("span2");
        tagBuilder.InnerHtml.SetHtmlContent("New HTML");
        tagBuilder.Attributes.Add("data-foo", "bar");
        tagBuilder.Attributes.Add("data-hello", "world");
 
        var generator = new Mock<IHtmlGenerator>(MockBehavior.Strict);
        var setup = generator
            .Setup(mock => mock.GenerateValidationMessage(
                It.IsAny<ViewContext>(),
                It.IsAny<ModelExplorer>(),
                It.IsAny<string>(),
                expectedMessage,
                It.IsAny<string>(),
                It.IsAny<object>()))
            .Returns(tagBuilder);
 
        var validationMessageTagHelper = new ValidationMessageTagHelper(generator.Object)
        {
            For = CreateModelExpression("Hello")
        };
        var output = new TagHelperOutput(
            "span",
            attributes: new TagHelperAttributeList(),
            getChildContentAsync: (useCachedResult, encoder) =>
            {
                var tagHelperContent = new DefaultTagHelperContent();
                tagHelperContent.SetContent(childContent);
                return Task.FromResult<TagHelperContent>(tagHelperContent);
            });
 
        var context = new TagHelperContext(
            tagName: "span",
            allAttributes: new TagHelperAttributeList(
                Enumerable.Empty<TagHelperAttribute>()),
            items: new Dictionary<object, object>(),
            uniqueId: "test");
 
        var viewContext = CreateViewContext();
        validationMessageTagHelper.ViewContext = viewContext;
 
        // Act
        await validationMessageTagHelper.ProcessAsync(context, output);
 
        // Assert
        Assert.Equal("span", output.TagName);
        Assert.Equal(2, output.Attributes.Count);
        var attribute = Assert.Single(output.Attributes, attr => attr.Name.Equals("data-foo"));
        Assert.Equal("bar", attribute.Value);
        attribute = Assert.Single(output.Attributes, attr => attr.Name.Equals("data-hello"));
        Assert.Equal("world", attribute.Value);
        Assert.Equal(expectedOutputContent, output.Content.GetContent());
    }
 
    [Fact]
    public async Task ProcessAsync_DoesNothingIfNullFor()
    {
        // Arrange
        var generator = new Mock<IHtmlGenerator>(MockBehavior.Strict);
        var validationMessageTagHelper = new ValidationMessageTagHelper(generator.Object);
        var expectedPreContent = "original pre-content";
        var expectedContent = "original content";
        var expectedPostContent = "original post-content";
        var output = new TagHelperOutput(
            tagName: "span",
            attributes: new TagHelperAttributeList(),
            getChildContentAsync: (useCachedResult, encoder) => Task.FromResult<TagHelperContent>(
                new DefaultTagHelperContent()));
        output.PreContent.SetContent(expectedPreContent);
        output.Content.SetContent(expectedContent);
        output.PostContent.SetContent(expectedPostContent);
 
        var context = new TagHelperContext(
            tagName: "span",
            allAttributes: new TagHelperAttributeList(
                Enumerable.Empty<TagHelperAttribute>()),
            items: new Dictionary<object, object>(),
            uniqueId: "test");
 
        var viewContext = CreateViewContext();
        validationMessageTagHelper.ViewContext = viewContext;
 
        // Act
        await validationMessageTagHelper.ProcessAsync(context, output);
 
        // Assert
        Assert.Equal("span", output.TagName);
        Assert.Empty(output.Attributes);
        Assert.Equal(expectedPreContent, output.PreContent.GetContent());
        Assert.Equal(expectedContent, output.Content.GetContent());
        Assert.Equal(expectedPostContent, output.PostContent.GetContent());
    }
 
    private static ModelExpression CreateModelExpression(string name)
    {
        var modelMetadataProvider = new EmptyModelMetadataProvider();
        return new ModelExpression(
            name,
            modelMetadataProvider.GetModelExplorerForType(typeof(object), model: null));
    }
 
    private static ViewContext CreateViewContext()
    {
        var actionContext = new ActionContext(
            new DefaultHttpContext(),
            new RouteData(),
            new ActionDescriptor());
 
        return new ViewContext(
            actionContext,
            Mock.Of<IView>(),
            new ViewDataDictionary(
                new EmptyModelMetadataProvider(),
                new ModelStateDictionary()),
            Mock.Of<ITempDataDictionary>(),
            TextWriter.Null,
            new HtmlHelperOptions());
    }
}