Created
April 25, 2010 00:08
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My implementation of the roman numerals kata (just the roman to arabic part).
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| # (Roman to Arabic only) | |
| class RomanNumerals | |
| def initialize | |
| @numerals = { | |
| "I" => 1, | |
| "V" => 5, | |
| "X" => 10, | |
| "L" => 50, | |
| "C" => 100, | |
| :eol => 0 } | |
| end | |
| def convert(value) | |
| sum = 0 | |
| glyphs = value.split('').push(:eol) | |
| previous_value = @numerals[glyphs.shift] | |
| glyphs.each do |glyph| | |
| this_value = @numerals[glyph] | |
| if previous_value >= this_value then | |
| sum += previous_value | |
| previous_value = this_value | |
| else | |
| previous_value = this_value - previous_value | |
| end | |
| end | |
| sum | |
| end | |
| end | |
| describe RomanNumerals do | |
| before :each do | |
| @rn = RomanNumerals.new | |
| end | |
| it 'should have a convert method' do | |
| @rn.should respond_to(:convert) | |
| end | |
| describe 'converting Roman to Arabic' do | |
| it 'should, given "I", return 1' do | |
| @rn.convert("I").should == 1 | |
| end | |
| it 'should, given "II", return 2' do | |
| @rn.convert("II").should == 2 | |
| end | |
| it 'should, given "III", return 3' do | |
| @rn.convert("III").should == 3 | |
| end | |
| it 'should, given "IV", return 4' do | |
| @rn.convert("IV").should == 4 | |
| end | |
| it 'should, given "V", return 5' do | |
| @rn.convert("V").should == 5 | |
| end | |
| it 'should, given "VI", return 6' do | |
| @rn.convert("VI").should == 6 | |
| end | |
| it 'should, given "VII", return 7' do | |
| @rn.convert("VII").should == 7 | |
| end | |
| it 'should, given "VIII", return 8' do | |
| @rn.convert("VIII").should == 8 | |
| end | |
| it 'should, given "IX", return 9' do | |
| @rn.convert("IX").should == 9 | |
| end | |
| it 'should convert X to 10' do | |
| @rn.convert("X").should == 10 | |
| end | |
| it 'should convert XIV to 14' do | |
| @rn.convert("XIV").should == 14 | |
| end | |
| it 'should convert XLII to 42' do | |
| @rn.convert("XLII").should == 42 | |
| end | |
| it 'should convert XCIX to 99' do | |
| @rn.convert("XCIX").should == 99 | |
| end | |
| it 'should convert CCCXCI to 391' do | |
| @rn.convert("CCCXCI").should == 391 | |
| end | |
| end | |
| end |
Yeah, I started out with "it 'should return Y, given X" which is just all sorts of backwards. I went to the "given X, return Y" format because I wanted the test to describe a basic left-to-right "from -> to" sequence. In later tests I switched to "should convert X to Y" which I actually like better because it has the name of the method in it, and it leaves the "from" closer to the "to".
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rad! i like the test names. i prefer the "given" convention, much like "given_when_then" convention. funny, i didn't write a SINGLE test today following "given when then" and didn't start any tests with (it "should....").