Beginnings of #25.

Author: AlexArchive

TestStack.FluentMVCTesting.Tests/ViewResultTestTests.cs

@@ -1,4 +1,5 @@
-using System.Web.Mvc;
+using System.Text.RegularExpressions;
+using System.Web.Mvc;
 using NUnit.Framework;
 
 namespace TestStack.FluentMVCTesting.Tests
@@ -71,7 +72,26 @@ public void Check_for_invalid_model_using_predicate()
             var exception = Assert.Throws<ViewResultModelAssertionException>(() =>
                 _viewResultTest.WithModel<TestViewModel>(m => m.Property1 == null)
             );
-            Assert.That(exception.Message, Is.EqualTo("Expected view model to pass the given condition, but it failed."));
+            Assert.That(exception.Message, Is.EqualTo(string.Format("Expected view model {{\"Property1\":\"{0}\",\"Property2\":{1}}} to pass the given condition (m => m.Property1 == null), but it failed.", _model.Property1, _model.Property2)));
+        }
+
+        [Test]
+        public void Check_for_invalid_model_using_predicate_with_two_conditions()
+        {
+            var exception = Assert.Throws<ViewResultModelAssertionException>(() =>
+                _viewResultTest.WithModel<TestViewModel>(m => m.Property1 == null && m.Property2 == 2)
+            );
+            Assert.That(exception.Message, Is.EqualTo(string.Format("Expected view model {{\"Property1\":\"{0}\",\"Property2\":{1}}} to pass the given condition (m => m.Property1 == null && m.Property2 == 2), but it failed.", _model.Property1, _model.Property2)));
+        }
+
+        [Test]
+        public void Check_for_invalid_model_using_predicate_with_closure()
+        {
+            int capturedOuterVariable = 2;
+            var exception = Assert.Throws<ViewResultModelAssertionException>(() =>
+                _viewResultTest.WithModel<TestViewModel>(m => m.Property1 == null && m.Property2 == capturedOuterVariable)
+            );
+            Assert.That(exception.Message, Is.EqualTo(string.Format("Expected view model {{\"Property1\":\"{0}\",\"Property2\":{1}}} to pass the given condition (m => m.Property1 == null AndAlso m.Property2 == 2), but it failed.", _model.Property1, capturedOuterVariable)));
         }
 
         [Test]

TestStack.FluentMvcTesting/ViewResultTest.cs

@@ -1,4 +1,7 @@
 using System;
+using System.Linq.Expressions;
+using System.Text.RegularExpressions;
+using System.Web.Helpers;
 using System.Web.Mvc;
 
 namespace TestStack.FluentMVCTesting
@@ -37,13 +40,21 @@ public ModelTest<TModel> WithModel<TModel>(TModel expectedModel) where TModel :
             return test;
         }
 
-        public ModelTest<TModel> WithModel<TModel>(Func<TModel, bool> predicate) where TModel : class
+        public ModelTest<TModel> WithModel<TModel>(Expression<Func<TModel, bool>> predicate) where TModel : class
         {
             var test = WithModel<TModel>();
 
             var model = _viewResult.Model as TModel;
-            if (!predicate(model))
-                throw new ViewResultModelAssertionException("Expected view model to pass the given condition, but it failed.");
+
+            var modelLex = Json.Encode(model);
+            var predicateLex = Regex.Replace(predicate.ToString(), "[()]", "");
+            var compiledPredicate = predicate.Compile();
+
+            if (!compiledPredicate(model))
+                throw new ViewResultModelAssertionException(string.Format(
+                    "Expected view model {0} to pass the given condition ({1}), but it failed.",
+                    modelLex, 
+                    predicateLex));
 
             return test;
         }