Ruby basic RSpec test does not pass - ruby

Question

I'm not able to understand why the following Rspec test does not pass -
require "rspec"
require_relative "file-to-be-tested"
describe Customer do
it "is valid with firstname" do
customer = Customer.new("handy")
expect(customer).to be_valid
end
end
for the corresponding Class definition -
class Customer
attr_reader :firstname
def initialize(firstname)
#firstname = firstname
end
end
these two code snippets are in separate files in the same folder, so when i run ~rspec <first-filename> in the terminal, I get the following error -
F
Failures:
1) Customer is valid with firstname
Failure/Error: expect(customer).to be_valid
expected #<Customer:0x007f90e50f3110> to respond to `valid?`
# ./poodr/poodr_rspec.rb:8:in `block (2 levels) in <top (required)>'
Finished in 0.00551 seconds (files took 0.52876 seconds to load)
1 example, 1 failure
Failed examples:
rspec ./poodr/poodr_rspec.rb:6 # Customer is valid with firstname

Answer 1

be_valid is an rspec-rails method, but it looks like you're using just straight rspec. you could do something like:
require "rspec"
require_relative "file-to-be-tested"
describe Customer do
it "is valid with firstname" do
expect { Customer.new('handy') }.to_not raise_error
end
end

Answer 2

What are you expecting the to be_valid test to do? The issue is that the Customer class has no method called valid? which your test is trying to test.
A hack to move your test along if your doing test driven development:
class Customer
def valid?
true
end
end
You now have a method called valid and your test will pass. Obviously it shouldn't always be true so your next step would be to expand the definition of valid?. What check needs to be done to know if a customer is valid or not?