Add ValidationMessageTagHelper tests.

Author: N. Taylor Mullen

test/Microsoft.AspNet.Mvc.TagHelpers.Test/ValidationMessageTagHelperTest.cs

@@ -0,0 +1,169 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.Collections.Generic;
+using System.IO;
+using System.Reflection;
+using Microsoft.AspNet.Http;
+using Microsoft.AspNet.Mvc.ModelBinding;
+using Microsoft.AspNet.Mvc.Rendering;
+using Microsoft.AspNet.Razor.Runtime.TagHelpers;
+using Microsoft.AspNet.Routing;
+using Moq;
+using Xunit;
+
+namespace Microsoft.AspNet.Mvc.TagHelpers
+{
+    public class ValidationMessageTagHelperTest
+    {
+        [Fact]
+        public void Process_CallsIntoGenerateValidationMessageWithExpectedParameters()
+        {
+            // Arrange
+            var validationMessageTagHelper = new ValidationMessageTagHelper
+            {
+                For = CreateModelExpression("Hello")
+            };
+            var called = false;
+            var output = new TagHelperOutput(
+                "span",
+                attributes: new Dictionary<string, string>(),
+                content: "Content of validation message");
+
+            var expectedViewContext = CreateViewContext();
+            var generator = new Mock<IHtmlGenerator>();
+            generator.Setup(mock =>
+                mock.GenerateValidationMessage(It.IsAny<ViewContext>(),
+                                               It.IsAny<string>(),
+                                               It.IsAny<string>(),
+                                               It.IsAny<string>(),
+                                               It.IsAny<object>()))
+                    .Callback<ViewContext, string, string, string, object>(
+                        (viewContext, name, message, tag, htmlAttributes) =>
+                        {
+                            called = true;
+
+                            Assert.Same(expectedViewContext, viewContext);
+                            Assert.Equal("Hello", name);
+                            Assert.Equal("Content of validation message", message);
+                            Assert.Equal("span", tag);
+                            Assert.Null(htmlAttributes);
+                        })
+                    .Returns(new TagBuilder("span"));
+
+            SetViewContextAndGenerator(validationMessageTagHelper, expectedViewContext, generator.Object);
+
+            // Act & Assert
+            validationMessageTagHelper.Process(context: null, output: output);
+
+            Assert.True(called);
+        }
+
+        [Fact]
+        public void Process_MergesTagBuilderFromGenerateValidationMessage()
+        {
+            // Arrange
+            var validationMessageTagHelper = new ValidationMessageTagHelper
+            {
+                For = CreateModelExpression("Hello")
+            };
+            var output = new TagHelperOutput(
+                "span",
+                attributes: new Dictionary<string, string>(),
+                content: "Content of validation message");
+            var tagBuilder = new TagBuilder("span2")
+            {
+                InnerHtml = "New HTML"
+            };
+
+            tagBuilder.Attributes.Add("data-foo", "bar");
+            tagBuilder.Attributes.Add("data-hello", "world");
+
+            var expectedViewContext = CreateViewContext();
+            var generator = new Mock<IHtmlGenerator>(MockBehavior.Strict);
+            generator.Setup(mock =>
+                mock.GenerateValidationMessage(It.IsAny<ViewContext>(),
+                                               It.IsAny<string>(),
+                                               It.IsAny<string>(),
+                                               It.IsAny<string>(),
+                                               It.IsAny<object>()))
+                    .Returns(tagBuilder);
+
+            SetViewContextAndGenerator(validationMessageTagHelper, expectedViewContext, generator.Object);
+
+            // Act
+            validationMessageTagHelper.Process(context: null, output: output);
+
+            // Assert
+            Assert.Equal(output.TagName, "span2");
+            Assert.Equal(2, output.Attributes.Count);
+            var attribute = Assert.Single(output.Attributes, kvp => kvp.Key.Equals("data-foo"));
+            Assert.Equal("bar", attribute.Value);
+            attribute = Assert.Single(output.Attributes, kvp => kvp.Key.Equals("data-hello"));
+            Assert.Equal("world", attribute.Value);
+            Assert.Equal("New HTML", output.Content);
+        }
+
+        [Fact]
+        public void Process_DoesNothingIfNullFor()
+        {
+            // Arrange
+            var validationMessageTagHelper = new ValidationMessageTagHelper();
+            var output = new TagHelperOutput(
+                "span",
+                attributes: new Dictionary<string, string>(),
+                content: "Content of validation message");
+
+            var expectedViewContext = CreateViewContext();
+            var generator = new Mock<IHtmlGenerator>(MockBehavior.Strict);
+
+            SetViewContextAndGenerator(validationMessageTagHelper, expectedViewContext, generator.Object);
+
+            // Act & Assert
+            validationMessageTagHelper.Process(context: null, output: output);
+
+            Assert.Equal("span", output.TagName);
+            Assert.Empty(output.Attributes);
+            Assert.Equal("Content of validation message", output.Content);
+        }
+
+        private static ModelExpression CreateModelExpression(string name)
+        {
+            return new ModelExpression(
+                name,
+                new ModelMetadata(
+                    new Mock<IModelMetadataProvider>().Object,
+                    containerType: null,
+                    modelAccessor: null,
+                    modelType: typeof(object),
+                    propertyName: string.Empty));
+        }
+
+        private static ViewContext CreateViewContext()
+        {
+            var actionContext = new ActionContext(
+                new Mock<HttpContext>().Object,
+                new RouteData(),
+                new ActionDescriptor());
+
+            return new ViewContext(
+                actionContext,
+                Mock.Of<IView>(),
+                new ViewDataDictionary(
+                    new DataAnnotationsModelMetadataProvider()),
+                new StringWriter());
+        }
+
+        private static void SetViewContextAndGenerator(ITagHelper tagHelper,
+                                                       ViewContext viewContext,
+                                                       IHtmlGenerator generator)
+        {
+            var tagHelperType = tagHelper.GetType();
+
+            tagHelperType.GetProperty("ViewContext", BindingFlags.NonPublic | BindingFlags.Instance)
+                         .SetValue(tagHelper, viewContext);
+            tagHelperType.GetProperty("Generator", BindingFlags.NonPublic | BindingFlags.Instance)
+                         .SetValue(tagHelper, generator);
+        }
+    }
+}