first approach, trying to learn TDD

germandz/fizzbuzz.rb

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+def fizz? number
+  (number%3 == 0) || (number.to_s.include?"3")
+end
+
+def buzz? number
+  (number%5 == 0)  || (number.to_s.include?"5")
+end
+
+def fizzbuzz? number
+  fizz?(number) && buzz?(number)
+end
+
+def output_for_number number
+  output = ""
+  output << "Fizz" if fizz? number
+  output << "Buzz" if buzz? number
+  output << "?" if fizzbuzz? number
+  output << number.to_s if output.empty?
+  output
+end
+
+def fizzbuzz
+  (1..100).inject("") { |result, number| result << output_for_number(number) << "\n"  }
+end

germandz/fizzbuzz_spec.rb

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+require File.dirname(__FILE__) + "/fizzbuzz.rb"
+
+describe "fizzbuzz" do
+
+  NEW_LINE_SEPARATOR = "\n"
+
+  def lines string
+    string.split(NEW_LINE_SEPARATOR)
+  end
+
+  def number_line_for_number number
+    number-1
+  end
+
+  it "must return 100 lines" do
+    lines(fizzbuzz).count.should == 100
+  end
+
+  it "must return 1 and 2 in the first two lines" do
+    lines(fizzbuzz)[number_line_for_number(1)].should == "1"
+    lines(fizzbuzz)[number_line_for_number(2)].should == "2"
+  end
+
+  it "must include 'Fizz' when line is for number 3" do
+    lines(fizzbuzz)[number_line_for_number(3)].should include "Fizz"
+  end
+
+  it "must include 'Fizz' when line is for a multiple of 3" do
+    (1..33).each do |base|
+    number = base*3
+      lines(fizzbuzz)[number_line_for_number(number)].should include "Fizz"
+    end
+  end
+
+  it "must include 'Buzz' when line is for number 5" do
+    lines(fizzbuzz)[number_line_for_number(5)].should include "Buzz"
+  end
+
+  it "must include 'Buzz' when line is for a multiple of 5" do
+    (1..20).each do |base|
+    number = base*5
+      lines(fizzbuzz)[number_line_for_number(number)].should include "Buzz"
+    end
+  end
+
+  it "must include '?' when line is for a multiple of 3 and 5" do
+    (1..6).each do |base|
+    number = base*3*5
+      lines(fizzbuzz)[number_line_for_number(number)].should include "?"
+    end
+  end
+
+  it "must include 'Fizz' when line is for a number including a 3" do
+    lines(fizzbuzz)[number_line_for_number(43)].should include "Fizz"
+  end
+
+  it "must include 'Buzz' when line is for a number including a 5" do
+    lines(fizzbuzz)[number_line_for_number(57)].should include "Buzz"
+  end
+
+end