Using the connectionstring in an nunit test

Question

Hi,

we use the nunit.exe application to run our (integration)test

Now i experience the problem that the connectionstring is not picked up from the app.config from the dll where the testcode is in.

That sounds logical because the nunit.exe is the starting app and not the test dll (it used to work when i started the tests from the visual studio testframework by the way), but should i put the connectionstrings in the nunit.exe.config?

I tried setting them in the testcode (works for the appsettings : ConfigurationManager.AppSettings.Set("DownloadDirectory", mDir);) like this: ConfigurationManager.ConnectionStrings.Add(conset); (where conset is a ConnectionStringSettings object), but then i get the error that the connectionstrings section is readonly.

What should i do to use the connectionstrings in my test?

EDIT: we use the entity framework so we can't put the connectionstring in the appsettings because it reads from the section directly, i couldn't find a way to work around this behaviour.

Answer 1

You can read Connection String Value from ConfigurationManager.AppSettings, yes it is readonly. You can change it in App.Config. If you want to change some values in connection string, for ex URL, in code you can change your dataContext.URL or any properties you want with coding.

Answer 2

I think for unit tests it may be much easy. you may put connection string into a test class directly as hardcoded string. in simple unit tests you test limited logic scope and not care of authentically of input arguments

Answer 3

Using reflection, you can (in memory) change your value of the Configuration.ConnectionStrings[connectionName], which in your case you would probably do in SetUp or perhaps TestFixtureSetUp. See http://david.gardiner.net.au/2008/09/programmatically-setting.html.

// Back up the existing connection string
ConnectionStringSettings connStringSettings = ConfigurationManager.ConnectionStrings[connectionName];
string oldConnectionString = connStringSettings.ConnectionString;

// Override the IsReadOnly method on the ConnectionStringsSection.
// This is something of a hack, but will work as long as Microsoft doesn't change the
// internals of the ConfigurationElement class.
FieldInfo fi = typeof(ConfigurationElement).GetField("_bReadOnly", BindingFlags.Instance | BindingFlags.NonPublic);
fi.SetValue(connStringSettings, false);

// Set the new connection string value
connStringSettings.ConnectionString = connectionStringNeededForNUnitTest;