day2

ruby/day2.rb

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+require 'minitest/autorun'
+
+class Tree
+  include Enumerable
+
+  attr_accessor :children, :node_name
+  def initialize(name, children=[]) @children = children
+    @node_name = name
+  end
+  def visit_all(&block)
+    visit(&block)
+    children.each {|c| c.visit_all(&block)}
+  end
+
+  alias :each :visit_all
+  def visit(&block)
+    block.call self
+  end
+
+  def self.build(hash)
+    hash.map {|name, children|
+      Tree.new(name, self.build(children))
+    }
+  end
+end
+
+class Hash
+  def to_tree
+  end
+end
+
+describe 'day 2' do
+  it 'opens files' do
+    File.open 'README.md' do |file|
+      # This will close when done
+      expect(file.each_line.first).wont_be_nil
+    end
+  end
+
+  it 'converts hashes to arrays' do
+    person = {name: 'Alice', age: 42, country: 'US'}
+    expect(person.to_a).must_equal [
+      [:name, 'Alice'],
+      [:age, 42],
+      [:country, 'US'],
+    ]
+  end
+
+  it 'converts arrays to hashes' do
+    car = [[:make, 'Ford'], [:model, 'Pinto'], [:top_speed, 35]]
+    expect(car.to_h).must_equal ({
+      make: 'Ford',
+      model: 'Pinto',
+      top_speed: 35,
+    })
+  end
+
+  it 'iterates through hashes' do
+    pokemon = {name: 'Pikachu', type: 'Electric', weight: 13.2}
+    pokemon.each do |key, value|
+      expect(pokemon[key]).must_equal value
+    end
+  end
+
+  it 'has stack-like arrays' do
+    stack = []
+    stack << 1 << 2 << 3
+    expect(stack.pop).must_equal 3
+    expect(stack.pop).must_equal 2
+    expect(stack.pop).must_equal 1
+  end
+
+  it 'has queue-like arrays' do
+    stack = []
+    stack << 1 << 2 << 3
+    expect(stack.shift).must_equal 1
+    expect(stack.shift).must_equal 2
+    expect(stack.shift).must_equal 3
+  end
+
+  it 'has lookup arrays' do
+    lookup = []
+    lookup << [:yogurt, :dairy] << [:carrot, :veggie] << [:tomato, :fruit]
+    expect(lookup.assoc(:yogurt)).must_equal [:yogurt, :dairy]
+    expect(lookup.assoc(:tomato)).must_equal [:tomato, :fruit]
+    lookup.unshift [:tomato, :veggie]
+    expect(lookup.assoc(:tomato)).must_equal [:tomato, :veggie]
+  end
+
+  it 'handles contents of 16 numbers' do
+    numbers = (0...16).to_a
+    numbers.each_slice(4) do |nums|
+      expect(nums.length).must_equal 4
+    end
+  end
+
+  it 'makes a tree' do
+
+    tree = Tree.build(
+      'grandpa' => {
+        'dad' => {
+          'child 1' => {},
+          'child 2' => {}
+        },
+        'uncle' => {
+          'child 3' => {},
+          'child 4' => {} 
+        } 
+      }
+    ).first
+
+    expect(tree.map &:node_name).must_equal ['grandpa', 'dad', 'child 1', 'child 2', 'uncle', 'child 3', 'child 4']
+  end
+
+
+end