为Asp.net控件写单元测试(ViewState)

namespace Eilon.Sample.Controls {
using System;
using System.Web.UI;
public class NewLabel : Control {
public string Text {
get {
string s = ViewState["Text"] as string;
return s ?? String.Empty;
}
set {
ViewState["Text"] = value;
}
}
protected override void Render(HtmlTextWriter writer) {
writer.Write(Text);
}
}
}

namespace Eilon.Sample.Controls.Test {
using System;
using System.IO;
using System.Web.UI;
using Microsoft.VisualStudio.TestTools.UnitTesting;
[TestClass]
public class NewLabelTest {
[TestMethod]
public void TextReturnsEmptyStringDefault() {
NewLabel label = new NewLabel();
Assert.AreEqual(String.Empty, label.Text,
"Default text should be empty string (not null)");
}
[TestMethod]
public void GetSetText() {
const string value = "Some Text";
NewLabel label = new NewLabel();
label.Text = value;
Assert.AreEqual(value, label.Text,
"Property value isn't the same as what we set");
}
[TestMethod]
public void RenderEmpty() {
NewLabel label = new NewLabel();
Assert.AreEqual(String.Empty, GetRenderedText(label),
"Shouldn't have rendered anything");
}
[TestMethod]
public void RenderWithText() {
const string value = "Some Text";
NewLabel label = new NewLabel();
label.Text = value;
Assert.AreEqual(value, GetRenderedText(label),
"Should have rendered the text");
}
private static string GetRenderedText(Control c) {
HtmlTextWriter writer = new HtmlTextWriter(new StringWriter());
c.RenderControl(writer);
return writer.InnerWriter.ToString();
}
}
}

// Interface to expose protected methods from
// the Control class to our unit test
internal interface IControl {
void LoadViewState(object savedState);
object SaveViewState();
void TrackViewState();
}

#region IControl Members
void IControl.LoadViewState(object savedState) {
LoadViewState(savedState);
}
object IControl.SaveViewState() {
return SaveViewState();
}
void IControl.TrackViewState() {
TrackViewState();
}
#endregion

[TestMethod]
public void TextSavedInViewState() {
// Create the control, start tracking viewstate,
// then set a new Text value
const string firstValue = "Some Text";
const string secondValue = "ViewState Text";
NewLabel label = new NewLabel();
label.Text = firstValue;
((IControl)label).TrackViewState();
label.Text = secondValue;
// Save the control's state
object viewState = ((IControl)label).SaveViewState();
// Create a new control instance and load the state
// back into it, overriding any existing values
NewLabel newLabel = new NewLabel();
label.Text = firstValue;
((IControl)newLabel).LoadViewState(viewState);
Assert.AreEqual(secondValue, newLabel.Text,
"Value restored from viewstate does not match the original value we set");
}

using System.Runtime.CompilerServices;
[assembly: InternalsVisibleTo("MyControlLibrary.Test")]