The Unit test database related method is an error, and the object reference is not set to an instance of the object.

Because the link settings for the database are in Web. config, there is no web.confg file in the unit test project. Therefore, a "web. config" is also required in the Unit test project.
But unit testing is not a Web project, and the default read is not a. config file, but a unit project name. Dll.config, so you need to copy the Web. config to the unit test output directory and rename it.
If the unit test project is named: Producttest, the compiled output directory is bin/debug. Then copy the Web. config to the Bin/debug folder and change the name to: ProductTest.dll.config;

The Unit test database related method is an error, and the object reference is not set to an instance of the object.