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abhinav-29's solution

to Two Fer in the Bash Track

Published at Aug 01 2020 · 0 comments
Test suite

Two-fer or 2-fer is short for two for one. One for you and one for me.

Given a name, return a string with the message:

One for name, one for me.

Where "name" is the given name.

However, if the name is missing, return the string:

One for you, one for me.

Here are some examples:

Name String to return
Alice One for Alice, one for me.
Bob One for Bob, one for me.
One for you, one for me.
Zaphod One for Zaphod, one for me.

Run the tests with:

bats two_fer_test.sh

After the first test(s) pass, continue by commenting out or removing the [[ $BATS_RUN_SKIPPED == true ]] || skip annotations prepending other tests.

To run all tests, including the ones with skip annotations, run:

BATS_RUN_SKIPPED=true bats two_fer_test.sh



External utilities

Bash is a language to write "scripts" -- programs that can call external tools, such as sed, awk, date and even programs written in other programming languages, like Python. This track does not restrict the usage of these utilities, and as long as your solution is portable between systems and does not require installation of third party applications, feel free to use them to solve the exercise.

For an extra challenge, if you would like to have a better understanding of the language, try to re-implement the solution in pure Bash, without using any external tools. Note that there are some types of problems that bash cannot solve, such as performing floating point arithmetic and manipulating dates: for those, you must call out to an external tool.

Submitting Incomplete Solutions

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


#!/usr/bin/env bash

# local version:

@test "no name given" {
  #[[ $BATS_RUN_SKIPPED == "true" ]] || skip

  # The above line controls whether to skip the test.
  # Normally, we skip every test except for the first one
  # (the first one is always commented out).  This allows for
  # a person to focus on solving a test at a time: you can
  # comment out or delete the
  # `[[ $BATS_RUN_SKIPPED == "true" ]] || skip`
  # line to run the test when you are ready.
  # You can also run all the tests by setting the
  # `$BATS_RUN_SKIPPED` environment variable, like this:
  #     $ BATS_RUN_SKIPPED=true bats two_fer_test.sh

  run bash two_fer.sh
  (( status == 0 ))
  [[ $output == "One for you, one for me." ]]

@test "a name given" {
  [[ $BATS_RUN_SKIPPED == "true" ]] || skip
  run bash two_fer.sh Alice
  (( status == 0 ))
  [[ $output == "One for Alice, one for me." ]]

@test "another name given" {
  [[ $BATS_RUN_SKIPPED == "true" ]] || skip
  run bash two_fer.sh Bob
  (( status == 0 ))
  [[ $output == "One for Bob, one for me." ]]

# bash-specific test: Focus the student's attention on the effects of
# word splitting and filename expansion:
# https://www.gnu.org/software/bash/manual/bash.html#Shell-Expansions

@test "handle arg with spaces" {
  [[ $BATS_RUN_SKIPPED == "true" ]] || skip
  run bash two_fer.sh "John Smith" "Mary Ann"
  (( status == 0 ))
  [[ $output == "One for John Smith, one for me." ]]

@test "handle arg with glob char" {
  [[ $BATS_RUN_SKIPPED == "true" ]] || skip
  run bash two_fer.sh "*"
  (( status == 0 ))
  [[ $output == "One for *, one for me." ]]
if [ -z "$name" ]
echo One for "$name", one for me.

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