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// Copyright (c) Microsoft Corporation. All rights reserved. See License.txt in the project root for license information.
using System.Linq.Expressions;
using Xunit;
using Assert = Microsoft.TestCommon.AssertEx;
namespace System.Web.Mvc.Test
{
public class ExpressionHelperTest
{
[Fact]
public void StringBasedExpressionTests()
{
ViewDataDictionary vdd = new ViewDataDictionary();
// Uses the given expression as the expression text
Assert.Equal("?", ExpressionHelper.GetExpressionText("?"));
// Exactly "Model" (case-insensitive) is turned into empty string
Assert.Equal(String.Empty, ExpressionHelper.GetExpressionText("Model"));
Assert.Equal(String.Empty, ExpressionHelper.GetExpressionText("mOdEl"));
// Beginning with "Model" is untouched
Assert.Equal("Model.Foo", ExpressionHelper.GetExpressionText("Model.Foo"));
}
[Fact]
public void LambdaBasedExpressionTextTests()
{
// "Model" at the front of the expression is excluded (case insensitively)
DummyContactModel Model = null;
Assert.Equal(String.Empty, ExpressionHelper.GetExpressionText(Lambda<object, DummyContactModel>(m => Model)));
Assert.Equal("FirstName", ExpressionHelper.GetExpressionText(Lambda<object, string>(m => Model.FirstName)));
DummyContactModel mOdeL = null;
Assert.Equal(String.Empty, ExpressionHelper.GetExpressionText(Lambda<object, DummyContactModel>(m => mOdeL)));
Assert.Equal("FirstName", ExpressionHelper.GetExpressionText(Lambda<object, string>(m => mOdeL.FirstName)));
// Model property of model is passed through
Assert.Equal("Model", ExpressionHelper.GetExpressionText(Lambda<DummyModelContainer, DummyContactModel>(m => m.Model)));
// "Model" in the middle of the expression is not excluded
DummyModelContainer container = null;
Assert.Equal("container.Model", ExpressionHelper.GetExpressionText(Lambda<object, DummyContactModel>(m => container.Model)));
Assert.Equal("container.Model.FirstName", ExpressionHelper.GetExpressionText(Lambda<object, string>(m => container.Model.FirstName)));
// The parameter is excluded
Assert.Equal(String.Empty, ExpressionHelper.GetExpressionText(Lambda<DummyContactModel, DummyContactModel>(m => m)));
Assert.Equal("FirstName", ExpressionHelper.GetExpressionText(Lambda<DummyContactModel, string>(m => m.FirstName)));
// Integer indexer is included and properly computed from captured values
int x = 2;
Assert.Equal("container.Model[42].Length", ExpressionHelper.GetExpressionText(Lambda<object, int>(m => container.Model[x * 21].Length)));
Assert.Equal("[42]", ExpressionHelper.GetExpressionText(Lambda<int[], int>(m => m[x * 21])));
// String indexer is included and properly computed from captured values
string y = "Hello world";
Assert.Equal("container.Model[Hello].Length", ExpressionHelper.GetExpressionText(Lambda<object, int>(m => container.Model[y.Substring(0, 5)].Length)));
// Back to back indexer is included
Assert.Equal("container.Model[1024][2]", ExpressionHelper.GetExpressionText(Lambda<object, char>(m => container.Model[x * 512][x])));
// Multi-parameter indexer is excluded
Assert.Equal("Length", ExpressionHelper.GetExpressionText(Lambda<object, int>(m => container.Model[42, "Hello World"].Length)));
// Single array indexer is included
Assert.Equal("container.Model.Array[1024]", ExpressionHelper.GetExpressionText(Lambda<object, int>(m => container.Model.Array[x * 512])));
// Double array indexer is excluded
Assert.Equal("", ExpressionHelper.GetExpressionText(Lambda<object, int>(m => container.Model.DoubleArray[1, 2])));
// Non-indexer method call is excluded
Assert.Equal("Length", ExpressionHelper.GetExpressionText(Lambda<object, int>(m => container.Model.Method().Length)));
// Lambda expression which involves indexer which references lambda parameter throws
Assert.Throws<InvalidOperationException>(
() => ExpressionHelper.GetExpressionText(Lambda<string, char>(s => s[s.Length - 4])),
"The expression compiler was unable to evaluate the indexer expression '(s.Length - 4)' because it references the model parameter 's' which is unavailable.");
}
// Helpers
private LambdaExpression Lambda<T1, T2>(Expression<Func<T1, T2>> expression)
{
return expression;
}
class DummyContactModel
{
public string FirstName { get; set; }
public string this[int index]
{
get { return index.ToString(); }
}
public string this[string index]
{
get { return index; }
}
public string this[int index, string index2]
{
get { return index2; }
}
public int[] Array { get; set; }
public int[,] DoubleArray { get; set; }
public string Method()
{
return String.Empty;
}
}
class DummyModelContainer
{
public DummyContactModel Model { get; set; }
}
}
}
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