is it possible to override built-in Ruby methods? - ruby-on-rails

Question

I am working on a problem where I have to pass an rpsec test. The problem is that the method is using the same name as a built in ruby method .count
given that I cannot change the rspec test, is it possible to override .count to behave differently? if not, is there a better way to get around this?
here is the rspec test I am trying to pass
subject = FinancialSummary.one_day(user: user, currency: :usd)
expect(subject.count(:deposit)).to eq(2)
my code:
class FinancialSummary
def self.one_day(user: user, currency: currency)
one_day_range = Date.today.beginning_of_day..Date.today.end_of_day
find_transaction(user.id, currency).where(created_at: one_day_range)
end
def self.find_transaction(user_id, currency)
Transaction.where(user_id: user_id,
amount_currency: currency.to_s.upcase
)
end
end
output:
[#<Transaction:0x00007f9b39c2e9b8
id: 1,
user_id: 1,
amount_cents: 1,
amount_currency: "USD",
category: "deposit",
created_at: Sat, 10 Mar 2018 18:46:53 UTC +00:00,
updated_at: Sat, 10 Mar 2018 18:46:53 UTC +00:00>,
#<Transaction:0x00007f9b3d0dbc38
id: 2,
user_id: 1,
amount_cents: 2000,
amount_currency: "USD",
category: "deposit",
created_at: Sat, 10 Mar 2018 18:47:43 UTC +00:00,
updated_at: Sat, 10 Mar 2018 18:47:43 UTC +00:00>,
#<Transaction:0x00007f9b3d0b3fa8
id: 7,
user_id: 1,
amount_cents: 1200,
amount_currency: "USD",
category: "withdraw",
created_at: Mon, 05 Mar 2018 02:22:42 UTC +00:00,
updated_at: Tue, 06 Mar 2018 18:48:20 UTC +00:00>]
it is printing out, what I believe to be the correct information, up until the test attempts to count the transactions by their category: 'deposit'. Then I get this error message:
ActiveRecord::StatementInvalid: SQLite3::SQLException: no such column: deposit: SELECT COUNT(deposit) FROM "transactions" WHERE "transactions"."user_id" = ? AND "transactions"."amount_currency" = ?
EDITED FOR MORE INFO

Answer 1

Some Assumptions Were Made in the Writing of this answer and modifications may be made based on updated specifications
Overriding count is a bad idea because others who view or use your code will have no idea that this is not the count they know and understand.
Instead consider creating a scope for this like
class FinancialSummary < ApplicationRecord
scope :one_day, ->(user:,currency:) { where(user: user, currency: currency) } #clearly already a scope
scope :transaction_type, ->(transaction_type:) { where(category: transaction_type) }
end
then the test becomes
subject = FinancialSummary.one_day(user: user, currency: :usd)
expect(subject.transaction_type(:deposit).count).to eq(2)
SQL now becomes:
SELECT COUNT(*)
FROM
"transactions"
WHERE
"transactions"."user_id" = ?
AND "transactions"."amount_currency" = "usd"
AND "transactions"."category" = "deposit"
Still very understandable and easy to read without the need to destroy the count method we clearly just used.

Answer 2

It's not clear what object the count message is being sent to because I don't know what FinancialSummary.one_day(user: user, currency: :usd) returns, but it seems like you are saying count is a method on whatever it returns, that you can't change. What does FinancialSummary.one_day(user: user, currency: :usd).class return?
Perhaps one solution would be to alias it on that object by adding alias_method :count, :account_count and then in your test calling expect(subject.account_count(:deposit)).to eq(2)
It would be easier if you could post the FinancialSummary#one_day method in your question.