What you have is a valid ADO.NET connection string - but it's NOT a valid Entity Framework connection string.
The EF connection string would look something like this:
<add name="testEntities" connectionString="metadata=res://*/Model1.csdl|res://*/Model1.ssdl|res://*/Model1.msl;provider=System.Data.SqlClient;provider connection string="data source=(local);initial catalog=test;integrated security=True;multipleactiveresultsets=True;App=EntityFramework"" providerName="System.Data.EntityClient" />
Inside this connection string, you'll find the provider connection string= attribute which is basically your ADO.NET connection string:
provider connection string="data source=(local);initial catalog=test;integrated security=True;multipleactiveresultsets=True;App=EntityFramework""
So here, you need to change your server name and possibly other settings.
data source=....stands for your server (you can also useserver=.....)initial catalog=.....stands for your database (you can also usedatabase=....)