exercism fetch elixir bank-account

Bank Account

Simulate a bank account supporting opening/closing, withdrawals, and deposits of money. Watch out for concurrent transactions!

A bank account can be accessed in multiple ways. Clients can make deposits and withdrawals using the internet, mobile phones, etc. Shops can charge against the account.

Create an account that can be accessed from multiple threads/processes (terminology depends on your programming language).

It should be possible to close an account; operations against a closed account must fail.


Run the test file, and fix each of the errors in turn. When you get the first test to pass, go to the first pending or skipped test, and make that pass as well. When all of the tests are passing, feel free to submit.

Remember that passing code is just the first step. The goal is to work towards a solution that is as readable and expressive as you can make it.

Have fun!

Running tests

Execute the tests with:

$ elixir bob_test.exs

(Replace bob_test.exs with the name of the test file.)

Pending tests

In the test suites, all but the first test have been skipped.

Once you get a test passing, you can unskip the next one by commenting out the relevant @tag :pending with a # symbol.

For example:

# @tag :pending
test "shouting" do
  assert Bob.hey("WATCH OUT!") == "Whoa, chill out!"

Or, you can enable all the tests by commenting out the ExUnit.configure line in the test suite.

# ExUnit.configure exclude: :pending, trace: true

For more detailed information about the Elixir track, please see the help page.

Submitting Incomplete Solutions

It's possible to submit an incomplete solution so you can see how others have completed the exercise.