Prerequisite AI Programming Assignment

prob_spec.rb

# to run this file, in terminal window, do the following commands
# gem install rspec
# rspec prob_spec.rb

class Dice
	#you can code the class here
	
	#if you want to move the class code, move it to a file labelled as dice.rb
	#place the statement: require "dice"
	#at the top of this spec file
end

class Solve
	#you can code the class here
	
	#if you want to move the class code, move it to a file labelled as solve.rb
	#place the statement: require "solve"
	#at the top of this spec file
end

describe "Dice" do
	context "in context to initializing class variables" do
		it "should allow you to configure the number of sides for a dice, with each side having a label, and a unique probability" do
			dice = Dice.new(2, ["heads","tails"], [0.5,0.5])
			dice.number_of_choices.should == 2
			dice.choice_labels.should == ["heads","tails"]
			dice.("heads").should == 0.5
			dice.("tails").should == 0.5
		end
		
		it "should fail if you give it probability values that do not add up to 1" do
			expect { Dice.new(1,["heads"],[0.9]) }.should raise_error
		end
	end
end

describe "Solve" do
	it "should solve for the probability of a choice of events" do
		one_sided_die = Dice.new(1,"only side",[1.0])
		#Given 3 Dice and 5 Buckets, how many ways are there to place the Dice in the Buckets
		#Also known as k Choose n or 5 choose 3
		Solve.new(one_sided_die).choose(5, 3).should == 10
	end

  it "should solve for the probability of a list of ordered events" do
		four_sided_die = Dice.new(4, ["1","2","3","4"], [0.20,0.20,0.20,0.40])
		Solve.new(four_sided_die).prob_of_ordered_events(["1","4","2"]).should == 0.016
	end
	
	it "should solve for the probability of a set of unordered events" do
		two_sided_die = Dice.new(2,["heads","tails"],[0.5,0.5])
		Solve.new(two_sided_die).prob_of_unordered_events(["heads","tails"]).should == 0.5
	end
end

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