How to structure my RSpec test folders, files and database?

I have been developing in RoR for more than a year now, but I'm just starting to use tests, using RSpec.

For standard model/controller tests, I usually don't have any problem, but the issue is that I want to test some complicated functional processes, and don’t really know how to structure my testing folders/files/database.

Here is a basic structure for my application:

class Customer
  has_one    :wallet
  has_many :orders    
  has_many :invoices, through: :orders
  has_many :invoice_summaries
end

class Wallet
  belongs_to :customer
end

class Order
  has_one    :invoice
  belongs_to :customer
end

class Invoice
  belongs_to :order
  belongs_to :invoice_summary
end

class InvoiceSummary
  belongs_to :customer
  has_many  :invoices
end

The main issue is that I want to simulate the lifecycle of my object, meaning:

• Instantiating customers and wallets which will be used for all the tests (without reinitializing)

• Simulating the time flow, creating and updating multiple orders/invoice objects and some invoice_summaries.

For the creation and update of the orders/invoices/invoice_summaries, I would like to have methods like

def create_order_1
  # code specific to create my first order, return the created order
end

def create_order_2
  # code specific to create my second order, return the created order
end
.
.
.
def create_order_n
  # code specific to create my n-th order, return the created order
end

def bill_order(order_to_bill)
  # generic code to do the billing of the order passed as parameter
end

def cancel_order(order_to_cancel)
  # generic code to cancel the order passed as parameter
end

I’ve already found the gem Timecop for simulating the time flow. Hence, I would like to have an easy to understand final test that looks like

# Code for the initialization of customers and wallets object

describe "Wallet should be equal to 0 after first day" do
  Timecop.freeze(Time.new(2015,7,1))
  first_request = create_request_1
  first_request.customer.wallet.value.should? == 0
end

describe "Wallet should be equal to -30 after second day" do
  Timecop.freeze(Time.new(2015,7,2))
  bill_order(first_request)
  second_order = create_order_2
  first_request.customer.wallet.value.should? == -30
end

describe "Wallet should be equal to -20 after third day" do 
  Timecop.freeze(Time.new(2015,7,3))
  bill_order(second_request)
  cancel_order(first_request)
  first_request.customer.wallet.value.should? == -20
end

describe "Three first day invoice_summary should have 3 invoices" do
  Timecop.freeze(Time.new(2015,7,4))
  invoice_summary = InvoiceSummary.create(
      begin_date: Date.new(2015,7,1),
      end_date: Date.new(2015, 7,3)
  ) # real InvoiceSummary method
  invoice_summary.invoices.count.should? == 3
end

Does anyone already have such tests? Are there good practices for the structuring of object factories, writing tests and so on?

For example, I've been told that a good idea would be to put the Customer/Wallet creation in a db/seed.rb file, but I don't really know what to do with it afterwards.