Chossing connection string according to Environment Variable

Environment Variable Connection String

private static string GetConnectionString()
    {
        var environmentVariable = Environment.GetEnvironmentVariable("FunctionalTests");
        return environmentVariable == null 
            ? ConfigurationManager.ConnectionStrings["SchoolContext"].ConnectionString 
            : ConfigurationManager.ConnectionStrings["SchoolContext-FunctionalTests"].ConnectionString;
    }
    
    //Si esta setiado el valor de la variable de entorno FunctionalTests usa la base de datos para la prueba