ruby - hello world

ruby/hello-world/GETTING_STARTED.md

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+# Getting Started
+
+These exercises lean on Test-Driven Development (TDD), but they're not an
+exact match. If you want a gentle introduction to TDD using minitest in
+Ruby, see the "Intro to TDD" over at JumpstartLab:
+http://tutorials.jumpstartlab.com/topics/testing/intro-to-tdd.html
+
+The following steps assume that you are in the same directory as the test
+suite.
+
+You must have the `minitest` gem installed:
+
+    $ gem install minitest
+
+## Step 1
+
+Run the test suite. It's written using the Minitest framework, and can be
+run with ruby:
+
+    $ ruby hello_world_test.rb
+
+This will fail, complaining that there is no file called `hello_world`.
+
+To fix the error create an empty file called `hello_world.rb` in the same
+directory as the `hello_world_test.rb` file.
+
+## Step 2
+
+Run the test again. It will give you a new error, since now the file exists,
+but is empty and does not contain the expected code.
+
+Depending on what platform you are on, the error will look different, but
+the way to fix it will be the same.
+
+On Windows, it will complain about:
+
+    syntax error, unexpected end-of-input, expecting '('
+
+On OS X and Linux, the error will be something like:
+
+
+    # Running:
+
+    E
+
+    Finished in 0.001328s, 753.0121 runs/s, 0.0000 assertions/s.
+
+      1) Error:
+    HelloWorldTest#test_say_hi:
+    NameError: uninitialized constant HelloWorldTest::HelloWorld
+    Did you mean?  HelloWorldTest
+        hello_world_test.rb:19:in `test_say_hi'
+
+    1 runs, 0 assertions, 0 failures, 1 errors, 0 skips
+
+
+Within the first test, we are referencing a constant named `HelloWorld` when
+we say `HelloWorld.hello`. When Ruby sees a capitalized name like
+`HelloWorld`, it looks it up in a big huge list of all the constants it knows about,
+to see what it points to. It could point to anything, and often in Ruby we have
+constants that point to definitions of classes or modules.
+
+When it looks `HelloWorld` up in its list, it doesn't find anything, so we need
+to make one.
+
+### Fixing the Error
+
+To fix it, open up the hello_world.rb file and add the following code:
+
+    class HelloWorld
+    end
+
+## Step 3
+
+Run the test again.
+
+    1) Error:
+    HelloWorldTest#test_no_name:
+    NoMethodError: undefined method `hello' for HelloWorld:Class
+        hello_world_test.rb:20:in `test_no_name'
+
+This time we have a `HelloWorld`, but we're trying tell it to `hello`, and
+`HelloWorld` doesn't understand that message.
+
+Open up hello_world.rb and add a method definition inside the class:
+
+    class HelloWorld
+      def self.hello
+      end
+    end
+
+## Step 4
+
+Run the test again.
+
+    1) Failure:
+    HelloWorldTest#test_no_name [hello_world_test.rb:11]:
+    When given no name, we should greet the world.
+    Expected: "Hello, World!"
+      Actual: nil
+
+Up until now we've been getting errors, this time we get a failure.
+
+An error means that Ruby cannot even run properly because of things like missing
+files or syntax errors, or referring to things that don't exist.
+
+A failure is different. A failure is when Ruby is running just fine
+and the test is expecting one outcome, but getting another.
+
+The test is expecting the `hello` method to return the string `"Hello, World!"`. The easiest way
+to make it pass, is to simply stick the string `"Hello, World!"` inside the method definition.
+
+## Step 5
+
+Run the test again.
+
+If it fails you're going to need to read the error message carefully to figure
+out what went wrong, and then try again.
+
+If it passes, then you're ready to move to the next step.
+
+## Submit
+
+When everything is passing, you can submit your code with the following
+command:
+
+    $ exercism submit hello_world.rb
+

ruby/hello-world/README.md

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+# Hello World
+
+The classical introductory exercise. Just say "Hello, World!".
+
+["Hello, World!"](http://en.wikipedia.org/wiki/%22Hello,_world!%22_program) is
+the traditional first program for beginning programming in a new language
+or environment.
+
+The objectives are simple:
+
+- Write a function that returns the string "Hello, World!".
+- Run the test suite and make sure that it succeeds.
+- Submit your solution and check it at the website.
+
+If everything goes well, you will be ready to fetch your first real exercise.
+
+* * * *
+
+For installation and learning resources, refer to the
+[exercism help page](http://exercism.io/languages/ruby).
+
+For running the tests provided, you will need the Minitest gem. Open a
+terminal window and run the following command to install minitest:
+
+    gem install minitest
+
+If you would like color output, you can `require 'minitest/pride'` in
+the test file, or note the alternative instruction, below, for running
+the test file.
+
+Run the tests from the exercise directory using the following command:
+
+    ruby hello_world_test.rb
+
+To include color from the command line:
+
+    ruby -r minitest/pride hello_world_test.rb
+
+
+## Source
+
+This is an exercise to introduce users to using Exercism [http://en.wikipedia.org/wiki/%22Hello,_world!%22_program](http://en.wikipedia.org/wiki/%22Hello,_world!%22_program)
+
+## Submitting Incomplete Solutions
+It's possible to submit an incomplete solution so you can see how others have completed the exercise.

ruby/hello-world/hello_world.rb

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+module HelloWorld
+  def self.hello
+    "Hello, World!"
+  end
+end

ruby/hello-world/hello_world_test.rb

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+begin
+  gem 'minitest', '>= 5.0.0'
+  require 'minitest/autorun'
+  require_relative 'hello_world'
+rescue Gem::LoadError => e
+  puts "\nMissing Dependency:\n#{e.backtrace.first} #{e.message}"
+  puts 'Minitest 5.0 gem must be installed for the Ruby track.'
+rescue LoadError => e
+  puts "\nError:\n#{e.backtrace.first} #{e.message}"
+  puts DATA.read
+  exit 1
+end
+
+# Common test data version: 1.1.0 be3ae66
+class HelloWorldTest < Minitest::Test
+  def test_say_hi
+    # skip
+    assert_equal "Hello, World!", HelloWorld.hello
+  end
+end
+
+__END__
+
+*****************************************************
+You got an error, which is exactly as it should be.
+This is the first step in the Test-Driven Development
+(TDD) process.
+
+The most important part of the error is
+
+   cannot load such file
+
+It's looking for a file named hello_world.rb that doesn't
+exist yet.
+
+To fix the error, create an empty file named hello_world.rb
+in the same directory as the hello_world_test.rb file.
+
+Then run the test again.
+
+For more guidance as you work on this exercise, see
+GETTING_STARTED.md.
+*****************************************************