Enums Exercises
Setup
Clone this repository:
$ cd ~/turing/1module/
$ git clone https://github.com/turingschool/enums-exercises.git
$ cd enums-exercises
How the Exercises are Organized
These exercises are broken up by method -- each enumerable method will be covered by
2 test files. In one test file, we'll practice using the enumerable
in question (map
, find
, etc). In the other, we'll look at how the enumerable
might be implemented in terms of the fundamental each
method.
Remember that all the enumerable methods are implemented in terms of each
,
so by looking at the methods in this way, we'll gain some insight
into how each method is put together under the hood.
Solving the Exercises
After cloning the repository down, and checking out a new branch, we are ready to get started on these enumerables exercises.
The goal of these exercises is to help you understand enumerables, both how they work and how they can be replicated through the use of the #each, the basis of all enumerables.
For each method, there are two files of interest. Let's look at map
as an example:
exercises/map_pattern_test.rb
exercises/map_test.rb
In the map_pattern_test.rb
you'll find a collection of exercises which do what map
is good at,
but they do it just with each
. This file will give us some insight into how map works internally,
hopefully helping us gain a deeper understanding around when we might use each one.
Then, in the other file, map_test.rb
you'll find the same examples using map
itself.
These examples will generally be much more concise, and will give a good demonstration
of how using the appropriate enumerable method (as opposed to doing everything with each
)
can make our lives much easier!
Running the Test Files
To run each example, we'll simply use the ruby
command in combination with the
path to that file. For example to run the 2 map files above, we would use:
ruby exercises/map_pattern_test.rb
and ruby exercises/map_test.rb
, respectively.
Recommended Exercise Order
You should perform the exercises in the order below:
map
select
find
(akadetect
)sort_by
count
reject
reduce
any?
all?
none?
one?
group_by
zip
You should perform the pattern test first, and then the test.
For example, you should work on map_pattern_test.rb
followed by map_test.rb
Upon completing that, you should do select_pattern_test.rb
and then
select_test.rb
and so forth.
Recommended Workflow
Here's how we recommend you work through the exercises:
- Open your text editor with two panes (left and right)
- In the left pane, open the pattern file like
map_pattern_test.rb
- In the right pane, open the matching file like
map_test.rb
- Run the
map_pattern_test.rb
and solve the first exercise - Run the
map_test.rb
and solve the same exercise - Repeat for each matching pair of exercises
- Commit your solutions after finishing each file
Contributing Patches
Fixing Errors in Exercises
If you find an error in one of the exercises, then it needs to be fixed upstream in the generators or templates.
For example, someone discovered that there were two tests with the same name in the all_pattern_test.rb
exercise:
def test_all_gone
skip
words = ["gone", "gone", "gone", "gone", "gone", "gone", "gone"]
all_gone = true
# Your code goes here
assert all_gone
end
def test_all_gone
skip
words = ["gone", "gone", "gone", "gone", "gone", "there", "gone", "gone"]
# Your code goes here
refute all_gone
end
The second test should have been named test_not_all_gone
.
In order to fix this, we need to locate the problem generator: lib/generator/all_problem.rb
.
exercise << Problem.new(
"all_gone",
{"words" => %w(gone gone gone gone gone gone gone)},
{"all_gone" => "assert"},
"word == 'gone'"
).assignment!
exercise << Problem.new(
"all_gone",
{"words" => %w(gone gone gone gone gone there gone gone)},
{"all_gone" => "refute"},
"word == 'gone'"
)
The name of the second problem can be changed.
Then regenerate the exercises with:
rake generate
Finally, run the tests:
rake test
Creating New Exercises
Check out master:
$ git checkout master
Create a new branch:
$ git checkout -b new-exercises
Make up one extra test for each test suite. Remember to delete the implementation once it's passing, and add a skip
to it.
$ git diff
$ git add -A
$ git commit -m "Add more exercises"
Push your branch up to GitHub:
$ git push -u origin new-exercises
Submit a pull request (go to the front page of your own enums-exercises
repository, there should be a button to compare/create a pull request for the branch that you just pushed up).
Keeping in sync with the upstream repository
origin
is your fork of the project. We'll need to connect to the upstream repository.
To do this, add a new remote named upstream that points to the Turing School repository:
$ git remote add upstream git@github.com:turingschool/enums-exercises.git
Then pull down the updated version of upstream:
$ git fetch upstream
And now make sure you're on master:
$ git checkout master
$ git branch # should say *master
Make master point to the exact commit that upstream/master is pointing at:
$ git reset --hard upstream/master
License
The MIT License (MIT)
Copyright (c) 2014 Jumpstart Lab