Changing App.Config on the fly for unit testing

First of all, a short description and the problem which I've faced. Our team has a list of unit tests that are more likely to integration tests. These tests before starting deploy database make some changes in the current environment and after running drop database and return environment back to its initial state. Of course, all configuration such as database connection strings and other we put to App.Config. Each of us runs these tests on a local machine using ReSharper and everything was fine until we had decided to run tests on build-machine sing standard "nunit-console" application. We created a standalone NUnit solution where we put all references on all test projects. When we tried to run tests on build-machine, we found out that all NUnits have requirement that app.confing should have the same name as as NUnit project + . config, i.e., we had to unite our dozens of app.configs in one.

Our solution is to change app.config before each test will be run.

Here is the code example to do it:

[SetUp]
public void SetUp()
{
    ServiceTestEnvironment.SetAssemblyConfig(GetType().Assembly)
}

SetUp of NUnit framework guarantees that method marked with this attribute will be invoked before any test. So we change app.config before running tests.

Here is the implementation of SetAssemblyConfig:

public static void SetAssemblyConfig(Assembly assembly)
{
	Configuration currentConfiguration = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
	Configuration assemblyConfiguration = ConfigurationManager.OpenExeConfiguration(new Uri(assembly.CodeBase).LocalPath);
	if (assemblyConfiguration.HasFile && string.Compare(assemblyConfiguration.FilePath, currentConfiguration.FilePath, true) != 0)
	{
	assemblyConfiguration.SaveAs(currentConfiguration.FilePath);
				ConfigurationManager.RefreshSection("appSettings");
	ConfigurationManager.RefreshSection("connectionStrings");	
	}
}

I've posted this tip because I couldn't find anything about this topic. Hope it can help somebody and saves time on debugging and tracing unit tests.