Дата: 2019-09-08
The goal of this blog entry is to explain how you can create integration tests for ASP.NET MVC applications by using a combination of Selenium WebDriver and IISExpress.
Integration tests are useful when you want to test an entire user story. For example, you might want to test whether a user can successfully add an item to a shopping cart. Adding an item to a shopping cart might require the execution of C# code, database code, and JavaScript code. Using an integration test, you can verify that the entire process of buying an item from your website works.
Typically, an integration test is contrasted with a unit test. A unit test is used to test a unit of code in isolation. A unit test is typically used to verify the behavior of a single method (Does the AddNumbers() method return the right value?). An integration test is used to test many components and methods working together (Can a user add an item to a shopping cart?).
Normally, unit tests are created by developers while they write the code for an application. Integration tests, in contrast, are typically written by Quality Assurance engineers after code has been written.
Another important difference between unit tests and integration tests are the speed of the tests. Unit tests must be fast. Typically, you run your unit tests each and every time a developer checks in code. Integration tests, in contrast, might be much slower than unit tests. Typically, you run all of your integration tests once a day in the middle of the night. Because integration tests require the execution of actual browsers, integration tests can be agonizingly slow.
The ASP.NET MVC framework was designed from the ground up to make it easy to write unit tests for your code. For example, you can unit test your controller actions without spinning up a web server.
On the other hand, the ASP.NET MVC framework has no built-in support for integration tests. If you want to write integration tests then you need a way to simulate the interactions of a web browser with your ASP.NET MVC application. In this blog entry, you learn how to use the open-source Selenium WebDriver testing framework to build integration tests which work with ASP.NET MVC.
In an integration test, you perform a test against a live website. Therefore, the first problem that we must solve is how to launch a live website automatically when executing tests with Visual Studio.
======== Begin Note ====== Visual Studio supports a type of test called an ASP.NET Unit Test which starts the ASP.NET Developer Web Server (Cassini) automatically. In other words, an ASP.NET Unit Test does exactly what we want. You create an ASP.NET Unit Test by adding three special attributes to a test method:[TestMethod()][HostType(“ASP.NET”)][UrlToTest(“http://localhost:25153/Home/Index”)][AspNetDevelopmentServerHost(@”C:TestSelenium”, “/”)]public void TestMethod1() {…}Unfortunately, ASP.NET Unit Tests only work with ASP.NET Web Form applications and not ASP.NET MVC applications. The [URLToTest] attribute must point at an ASP.NET Web Forms page. This attribute does not work with ASP.NET MVC controller actions. Therefore, if we want to launch a web server when performing a test with an ASP.NET MVC application, we must take on the responsibility of launching the web server ourselves. ========= End Note ==============
We’ll start a live website by taking advantage of IISExpress. IISExpress is a lightweight version of IIS that you can start from the command-line. You get IISExpress automatically when you install Visual Studio 2010 Service Pack 1 using the Microsoft Web Platform Installer. IISExpress is also available as a separate download using the Web Platform Installer.
After you install IISExpress, you can run iisexpress.exe from the command line. Open a command prompt and switch to either your Program FilesIIS Express or Program Files (x86)IIS Express directory (depending on your operating system). Next, enter the following command to launch a website located at the path c:MyWebsite using port 2020:
iisexpress /path:c:MyWebsite /port:2020
The IISExpress web server will keep running until you hit Q to quit. Each time you make a request against the MyWebsite site using a web browser, you’ll see the request logged to the window.
https://www.notion.so/c81659ec4c4a408dae920b6da4bd6b66#584781d4e8a84bbfa3bc81d1ea048803
Warning: You can only have one instance of IISExpress open at a particular port at a time. If you attempt to open IISExpress with the same port number twice then you will get an error.
We want to automate this process of starting IISExpress so that we can start IISExpress automatically in our tests. Listing 1 contains a base class named SeleniumTest.