.rspec

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+--format documentation
+--color

Gemfile

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+source 'https://rubygems.org'
+ruby '2.3'
+
+gem 'rspec'

Gemfile.lock

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+GEM
+  remote: https://rubygems.org/
+  specs:
+    diff-lcs (1.2.5)
+    rspec (3.5.0)
+      rspec-core (~> 3.5.0)
+      rspec-expectations (~> 3.5.0)
+      rspec-mocks (~> 3.5.0)
+    rspec-core (3.5.4)
+      rspec-support (~> 3.5.0)
+    rspec-expectations (3.5.0)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.5.0)
+    rspec-mocks (3.5.0)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.5.0)
+    rspec-support (3.5.0)
+
+PLATFORMS
+  ruby
+
+DEPENDENCIES
+  rspec
+
+RUBY VERSION
+   ruby 2.3.0p0
+
+BUNDLED WITH
+   1.13.3

README.md

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+Ruby Intro
+=============
+
+This 3-part homework gives some basic practice in Ruby as well as
+getting you accustomed to making testing a regular part of your workflow.
+
+Learning Goals
+--------------
+After completing this assignment, you will know how to:
+
+* Write simple code that uses basic constructs in the Ruby language, including methods and arguments, conditionals, string and array manipulation, regular expressions, and basic object-oriented programming mechanisms
+* Understand the Ruby project conventions for where code files and test files are located in a project's directory hierarchy
+* Run individual tests or suites of tests using the RSpec unit testing tool
+* Understand the basic syntax of RSpec unit tests
+ 
+Overview
+--------
+
+The repo for this assigment follows a fairly standard Ruby convention for codebases: the code
+files are stored in `lib/` and the test files are stored in `spec/`.
+(We use the RSpec unit-testing framework; if we were using Ruby's default
+framework, known as `Test::Unit`, the test files would be under
+`test/`.)
+
+We've placed "starter code" in `lib/ruby_intro.rb`; when you're all done, you
+can submit this single file to the autograder.
+
+However, you can test each of the 3 parts separately.  The files
+`spec/part[123]_spec.rb` contain RSpec tests for each of the three
+parts.  For example, to test your answers to Part 1, say `rspec
+spec/part1_spec.rb`.  `rspec` with no arguments runs the tests in all
+the files `spec/*_spec.rb`.
+
+* The line numbers in the RSpec error report will
+give you guidance as to which tests failed.  (You can check the [RSpec
+documentation](http://rspec.info) to see how the `.rspec` file can be
+used to customize the output format.)
+
+To ensure you have the rspec gem installed you need bundler and can then 
+run bundle install like so (if you accidently do not use c9 ide):
+
+```sh
+$ gem install bundler
+$ cd hw-ruby-intro
+$ bundle
+```
+
+When the above completes successfully you'll have RSpec installed and can
+run `rspec` from the command line to test your code.
+
+Before starting your homework, please refer to the recommanded workflow as below for this and future assignment:
+
+* Create a project with the name hw-ruby-intro in your Trustie workspace
+* Create a project repository with the name hw-ruby-intro in the setting page of the project
+* Link the project repository to this assignment
+* Clone the homework repository to your c9 ide workspace or anywhere you coding `$ git clone http://git.trustie.net/cgao/hw-ruby-intro.git`
+* Do your homework and test your solution
+* Commit change to your local git repository
+* Push your local repository at c9 workspace to your Trustie project repository
+* Submit your homework assignment
+
+Please refer to the Trustie user guide for creating project, repository, and using basic git command to manage your code repositories.
+
+# 1. Arrays, Hashes, and Enumerables
+
+Check the [Ruby 2.x documentation](http://ruby-doc.org) on `Array`,
+`Hash` and `Enumerable` as they could help tremendously with these
+exercises. :-) 
+
+0. Define a method `sum(array)` that takes an array of integers as an argument and returns the sum of its elements. For an empty array it should return zero.  Run associated tests via:  `$ rspec spec/part1_spec.rb:5`
+
+0. Define a method `max_2_sum(array)` which takes an array of integers as an argument and returns the sum of its two largest elements. For an empty array it should return zero. For an array with just one element, it should return that element. Run associated tests via:  `$ rspec spec/part1_spec.rb:23`
+
+0. Define a method `sum_to_n?(array, n)` that takes an array of integers and an additional integer, n, as arguments and returns true if any two elements in the array of integers sum to n. `sum_to_n?([], n)` should return false for any value of n, by definition. Run associated tests via:  `$ rspec spec/part1_spec.rb:42`
+
+You can check your progress on the all the above by running `$ rspec spec/part1_spec.rb`.
+
+# 2. Strings and Regular Expressions
+
+Check the documentation on String and Regexp as they could help tremendously with these exercises. :-)
+
+0. Define a method `hello(name)` that takes a string representing a name and returns the string "Hello, " concatenated with the name. Run associated tests via:  `$ rspec -e '#hello' spec/part2_spec.rb`
+
+0. Define a method `starts_with_consonant?(s)` that takes a string and returns true if it starts with a consonant and false otherwise. (For our purposes, a consonant is any letter other than A, E, I, O, U.) NOTE: be sure it works for both upper and lower case and for nonletters!  Run associated tests via:  `$ rspec -e '#starts_with_consonant?' spec/part2_spec.rb`
+
+0. Define a method `binary_multiple_of_4?(s)` that takes a string and returns true if the string represents a binary number that is a multiple of 4. NOTE: be sure it returns false if the string is not a valid binary number!  Run associated tests via:  `$ rspec -e '#binary_multiple_of_4?' spec/part2_spec.rb`
+
+You can check your progress on the all the above by running `$ rspec spec/part2_spec.rb`.
+
+# 3. Object Oriented Basics
+
+
+Define a class `BookInStock` which represents a book with an ISBN
+number, `isbn`, and price of the book as a floating-point number,
+`price`, as attributes. Run associated tests via:  `$ rspec -e 'getters and setters' spec/part3_spec.rb` 
+
+The constructor should accept the ISBN number
+(a string, since in real life ISBN numbers can begin with zero and can
+include hyphens) as the first argument and price as second argument, and
+should raise `ArgumentError` (one of Ruby's built-in exception types) if
+the ISBN number is the empty string or if the price is less than or
+equal to zero.  Include the proper getters and setters for these
+attributes. Run associated tests via:  `$ rspec -e 'constructor' spec/part3_spec.rb`
+
+Include a method `price_as_string` that returns the price of
+the book formatted with a leading dollar sign and two decimal places, that is, a price
+of 20 should format as "$20.00" and a price of 33.8 should format as
+"$33.80". Run associated tests via:  `$ rspec -e '#price_as_string' spec/part3_spec.rb`
+
+You can check your progress on the all the above by running `rspec spec/part3_spec.rb`.
+
+## More Challenges
+
+* Try getting setup with 
+an automated test framework such as [guard](http://code.tutsplus.com/tutorials/testing-your-ruby-code-with-guard-rspec-pry--cms-19974) or [autotest](https://rubygems.org/gems/autotest).  Guard or AutoTest can be set up so that 
+they will run all the tests in `spec/`, but every time you edit and save 
+your code file, the tests are automatically re-run, so you don't have to 
+run them manually.  As we'll see later, this is the "watch the test fail" 
+part of the TDD or test-driven process of development: write the tests before
+you write the code, watch the test fail, fill in the code and save the code file, 
+then watch the test pass!
+
+
+

lib/ruby_intro.rb

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+# When done, submit this entire file to the autograder.
+
+# Part 1
+
+def sum arr
+  # YOUR CODE HERE
+  sum = 0
+  arr.each do |i|
+    sum += i
+  end
+  return sum
+end
+
+def max_2_sum arr
+  # YOUR CODE HERE
+  if arr.size == 0
+    return 0
+  elsif arr.size == 1
+    return arr[0]
+  else
+    sum = 0
+    sum += arr.max
+    arr.delete_at arr.index(sum)
+    sum += arr.max
+    return sum
+  end
+end
+
+def sum_to_n? arr, n
+  # YOUR CODE HERE
+  if arr.size < 2
+    return false
+  end
+  arr.each_with_index do |first_number, i|
+    j = i + 1
+    while j < arr.size
+      if first_number + arr[j] == n
+        return true
+      end
+      j += 1
+    end
+  end
+  
+  return false
+end
+
+# Part 2
+
+def hello(name)
+  # YOUR CODE HERE
+  "Hello, " + name
+end
+
+def starts_with_consonant? s
+  # YOUR CODE HERE
+  if /^[^aeiouAEIOU]/ =~ s and /^[a-zA-Z]/ =~ s  # 必须不能一以原因以原音字母开头，而且必须以字母开头
+    return true
+  end
+  return false
+end
+
+def binary_multiple_of_4? s
+  # YOUR CODE HERE
+  if /[^01]/ =~ s  # 判断是否有效
+    return false
+  end
+  if s.size == 0
+    return false
+  end
+  if s.size == 1
+    return s == "0"
+  end
+  if s.size == 2
+    return s == "00"
+  end
+  if s[-2..-1].to_s.include?('1')
+    return false
+  else
+    return true
+  end
+end
+
+# Part 3
+
+class BookInStock
+# YOUR CODE HERE
+
+def initialize(isbn, price)
+  if isbn.empty? or price <= 0
+    raise ArgumentError
+  end
+  @isbn = isbn
+  @price = price
+end
+
+attr_accessor :isbn
+attr_accessor :price
+
+def price_as_string
+  format('$%.2f', @price)
+end
+
+end

spec/part1_spec.rb

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+require 'ruby_intro.rb'
+
+describe 'Ruby intro part 1' do
+
+  describe "#sum" do
+    it "should be defined" do
+      expect { sum([1,3,4]) }.not_to raise_error
+    end
+
+    it "returns correct sum [20 points]" , points: 20 do
+      expect(sum([1,2,3,4,5])).to be_a_kind_of Fixnum
+      expect(sum([1,2,3,4,5])).to eq(15)
+      expect(sum([1,2,3,4,-5])).to eq(5)
+      expect(sum([1,2,3,4,-5,5,-100])).to eq(-90)
+    end
+
+    it "works on the empty array [10 points]" , points: 10 do
+      expect { sum([]) }.not_to raise_error
+      expect(sum([])).to be_zero
+    end
+  end
+
+  describe "#max_2_sum" do
+    it "should be defined" do
+      expect { max_2_sum([1,2,3]) }.not_to raise_error
+    end
+    it "returns the correct sum [7 points]" , points: 7 do
+      expect(max_2_sum([1,2,3,4,5])).to be_a_kind_of Fixnum
+      expect(max_2_sum([1,-2,-3,-4,-5])).to eq(-1)
+    end
+    it 'works even if 2 largest values are the same [3 points]' , points: 3 do
+      expect(max_2_sum([1,2,3,3])).to eq(6)
+    end
+    it "returns zero if array is empty [10 points]" , points: 10 do
+      expect(max_2_sum([])).to be_zero
+    end
+    it "returns value of the element if just one element [10 points]" , points: 10 do
+      expect(max_2_sum([3])).to eq(3)
+    end
+  end
+
+  describe "#sum_to_n" do
+    it "should be defined" do
+      expect { sum_to_n?([1,2,3],4) }.not_to raise_error
+    end
+    it "returns true when any two elements sum to the second argument [30 points]" , points: 30 do
+      expect(sum_to_n?([1,2,3,4,5], 5)).to be true        # 2 + 3 = 5
+      expect(sum_to_n?([3,0,5], 5)).to be true            # 0 + 5 = 5
+      expect(sum_to_n?([-1,-2,3,4,5,-8], -3)).to be true  # handles negative sum
+      expect(sum_to_n?([-1,-2,3,4,5,-8], 12)).to be false # 3 + 4 + 5 = 12 (not 3 elements)
+      expect(sum_to_n?([-1,-2,3,4,6,-8], 12)).to be false # no two elements that sum
+    end
+    #    for rspec 2.14.1
+    # it "returns false for the single element array [5 points]" , points: 5 do
+    #   sum_to_n?([1], 1).should be_false
+    #   sum_to_n?([3], 0).should be_false
+    # end
+    # it "returns false for the empty array [5 points]" , points: 5 do
+    #   sum_to_n?([], 0).should be_false
+    #   sum_to_n?([], 7).should be_false
+    # end
+    it "returns false for any single element array [5 points]" , points: 5 do
+      expect(sum_to_n?([0], 0)).to be false
+      expect(sum_to_n?([1], 1)).to be false
+      expect(sum_to_n?([-1], -1)).to be false
+      expect(sum_to_n?([-3], 0)).to be false
+    end
+    it "returns false for an empty array [5 points]" , points: 5 do
+      expect(sum_to_n?([], 0)).to be false
+      expect(sum_to_n?([], 7)).to be false
+    end
+  end
+end

spec/part2_spec.rb

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+require 'ruby_intro.rb'
+
+describe "#hello" do
+  it "should be defined" do
+    expect { hello("Testing") }.not_to raise_error()#::NoMethodError)
+  end
+
+  it "The hello method returns the correct string [30 points]" , points: 30 do
+    expect(hello("Dan").class).to eq(String)
+    expect(hello("Dan")).to eq('Hello, Dan'), "Incorrect results for input: \"Dan\""
+    expect(hello("BILL")).to eq('Hello, BILL'), "Incorrect results for input: \"BILL\""
+    expect(hello("Mr. Ilson")).to eq('Hello, Mr. Ilson'), "Incorrect results for input: \"Mr. Ilson\""
+  end
+end
+
+describe "#starts_with_consonant?" do
+  it "should be defined" do
+    expect { starts_with_consonant?("d") }.not_to raise_error()#::NoMethodError)
+  end
+  it 'classifies true cases [10 points]' , points: 10 do
+    expect(starts_with_consonant?('v')).to be_truthy, "'v' is a consonant"
+    ['v', 'vest', 'Veeee', 'crypt'].each do |string|
+      expect(starts_with_consonant?(string)).to be_truthy, "Incorrect results for input: \"#{string}\""
+    end
+  end
+  it 'classifies false cases [10 points]' , points: 10 do
+    expect(starts_with_consonant?('a')).to be_falsy, "'a' is not a consonant"
+    ['asdfgh', 'Unix'].each do |string|
+      expect(starts_with_consonant?(string)).to be_falsy, "Incorrect results for input: \"#{string}\""
+    end
+  end
+  it 'works on the empty string [5 points]' , points: 5 do
+    expect(starts_with_consonant?('')).to be_falsy
+  end
+  it 'works on nonletters [5 points]' , points: 5 do
+    expect(starts_with_consonant?('#foo')).to be_falsy
+  end
+end
+
+describe "#binary_multiple_of_4?" do
+  it "should be defined" do
+    expect { binary_multiple_of_4?("yes") }.not_to raise_error()#::NoMethodError)
+  end
+  it "classifies valid binary numbers [30 points]" , points: 30 do
+    ["1010101010100", "0101010101010100", "100", "0"].each do |string|
+      expect(binary_multiple_of_4?(string)).to be_truthy,  "Incorrect results for input: \"#{string}\""
+    end
+    ["101", "1000000000001"].each do |string|
+      expect(binary_multiple_of_4?(string)).not_to be_truthy,  "Incorrect results for input: \"#{string}\""
+    end
+  end
+  it "rejects invalid binary numbers [10 points]" , points: 10 do
+    expect(binary_multiple_of_4?('a100')).to be_falsy, "'a100' is not a valid binary number!"
+    expect(binary_multiple_of_4?('')).to be_falsy, "The empty string is not a valid binary number!"
+  end
+end

spec/part3_spec.rb

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+require 'ruby_intro.rb'
+
+describe "BookInStock" do
+  it "should be defined" do
+    expect { BookInStock }.not_to raise_error
+  end
+
+  describe 'getters and setters' do
+    before(:each)  { @book = BookInStock.new('isbn1', 33.8) }
+    it 'should set ISBN [10 points]' , points: 10 do
+      expect(@book.isbn).to eq('isbn1')
+    end
+    it 'should set price [10 points]' , points: 10 do
+      expect(@book.price).to eq(33.8)
+    end
+    it 'should be able to change ISBN [10 points]' , points: 10 do
+      @book.isbn = 'isbn2'
+      expect(@book.isbn).to eq('isbn2')
+    end
+    it 'should be able to change price [10 points]' , points: 10 do
+      @book.price = 300.0
+      expect(@book.price).to eq(300.0)
+    end
+  end
+  describe 'constructor' do
+    it 'should reject invalid ISBN number [10 points]' , points: 10 do
+      expect { BookInStock.new('', 25.00) }.to raise_error(ArgumentError)
+    end
+    it 'should reject zero price [10 points]' , points: 10 do
+      expect { BookInStock.new('isbn1', 0) }.to raise_error(ArgumentError)
+    end
+    it 'should reject negative price [10 points]' , points: 10 do
+      expect { BookInStock.new('isbn1', -5.0) }.to raise_error(ArgumentError)
+    end
+  end
+  describe "#price_as_string" do
+    it "should be defined" do
+      expect(BookInStock.new('isbn1', 10)).to respond_to(:price_as_string)
+    end
+    it 'should display 33.95 as "$33.95" [10 points]' , points: 10 do
+      expect(BookInStock.new('isbn11', 33.95).price_as_string).to eq('$33.95')
+    end
+    it "should display 1.1 as $1.10 [10 points]" , points: 10 do
+      expect(BookInStock.new('isbn11', 1.1).price_as_string).to eq('$1.10')
+    end
+    it "should display 20 as $20.00 [10 points]" , points: 10 do
+      expect(BookInStock.new('isbn11', 20).price_as_string).to eq('$20.00')
+    end
+  end
+end