................................. ................................. ................................. ................................. ............................ 467 tests, 0 failures, 0 confidence Katrina Owen @kytrinyx JumpstartLab

Pointe •◀ .

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F F F F F F F F F

test results not implementation

results

command query separation . . . . . . . . . . . . . . . . . . ✂

returns a value, has no side effects query

has side effects, returns nil command

. . . . . . . . . . . . . . . . . ✂ command query

query @waiter.menu

command @bill.add(steak)

both ... it’s complicated

responsibility and collaboration

mock expectation

mock stub . . . . . . . . . . . . . . . . . ✂ assertion dumb value

who is responsible?

sender :message receiver outgoing incoming

incoming assert the state of the system

outgoing assert collaboration

rules of thumb

Query Incoming ?

Query Incoming assert return value

Query Command Incoming assert return value ?

Query Command Incoming assert return value assert side effects

Query Command Incoming Outgoing assert return value assert side effects ?

Query Command Incoming Outgoing assert return value assert side effects do not assert

Query Command Incoming Outgoing assert return value assert side effects do not assert ?

Query Command Incoming Outgoing assert return value assert side effects do not assert assert message sent

Query Command Incoming Private Outgoing assert return value assert side effects ? ? do not assert assert message sent

Query Command Incoming Private Outgoing assert return value assert side effects do not assert do not assert do not assert assert message sent

Query Command Incoming Private Outgoing assert return value assert side effects do not assert do not assert do not assert assert message sent

1incoming query assert return value

1incoming query assert return value assert_equal "...", @waiter.menu

assert direct, local side effects 2 incoming command

assert direct, local side effects 2 incoming command bill.add(steak)

assert direct, local side effects 2 bill.add(steak) assert_equal 32.90, bill.total incoming command

3outgoing query do not assert

3outgoing query do not assert chef.todays_special

assert message send 4 outgoing command

assert message send kitchen.expect(:order_up) 4 outgoing command

assert message send kitchen.expect(:order_up) waiter.i_would_like(:steak) 4 outgoing command

assert message send kitchen.expect(:order_up) waiter.i_would_like(:steak) kitchen.verify 4 outgoing command

assert message send 4 outgoing command kitchen.should_receive(:order_up) waiter.i_would_like(:steak)

5private message do not assert

5private message do not assert note_to_self(stuff)

unit test

unit test return values +

unit test return values + side effects +

unit test return values + side effects + critical interations +

unit test return values + side effects + critical interations + implementation details -

meet practice theory

github.com/it-agile codersdojo_client

@kata.generate 'ruby.rspec', 'prime'

code kata small coding exercise

@kata.generate 'ruby.rspec', 'prime'

@kata.generate 'ruby.rspec', 'prime'

@kata.generate 'ruby.rspec', 'prime'

@kata.generate 'ruby.rspec', 'prime'

class Prime def foo 'fixme' end end

class Prime def foo 'fixme' end end describe Prime do let(:prime) { Prime.new } its(:foo) { should == 'bar' } end

No content

limit work in progress

Query Command Incoming Private Outgoing ✓

incoming command assert direct, local side effects

describe Scaffolder do it "generates the files and directories" it "replaces placeholders" end

describe Scaffolder do before (:each) do @shell = mock @shell.should_receive(:shell_extension).any_number_of_times.and_return "cmd" @shell.should_receive(:remove_command_name).any_number_of_times.and_return "del" @shell.should_receive(:path_separator).any_number_of_times.and_return ";" @shell.should_receive(:dir_separator).any_number_of_times.and_return "/" Scaffolder.should_receive(:current_file).any_number_of_times.and_return("aDir/lib/aFile.rb") @scaffolder = Scaffolder.new @shell end it "generates the files and directories" do @shell.should_receive(:real_dir_entries).with("aDir/templates/a.template").and_return ["a", "b"] @shell.should_receive(:cp_r).with "aDir/templates/a.template/a", "." @shell.should_receive(:file?).with("a").and_return false @shell.should_receive(:cp_r).with "aDir/templates/a.template/b", "." @shell.should_receive(:file?).with("b").and_return fals @scaffolder.scaffold "a.template", 'myKata' end it "replaces placeholders" do @shell.should_receive(:real_dir_entries).with("aDir/templates/a.template").and_return ["a", "README", "run-once.sh", "run-endless.sh"] @shell.should_receive(:cp_r).with "aDir/templates/a.template/a", "." @shell.should_receive(:file?).with("a").and_return false @shell.should_receive(:cp_r).with "aDir/templates/a.template/README", "." @shell.should_receive(:file?).with("README").and_return true @shell.should_receive(:read_file).with("README").and_return '%rm% %kata_file%\nb.%sh%\nc%:%d' @shell.should_receive(:write_file).with "README", 'del myKata\nb.cmd\nc;d' @shell.should_receive(:cp_r).with "aDir/templates/a.template/run-once.sh", "." @shell.should_receive(:file?).with("run-once.sh").and_return true @shell.should_receive(:read_file).with("run-once.sh").and_return "%rm% a\nb.%sh%\nc%:%d" @shell.should_receive(:write_file).with "run-once.sh", "del a\nb.cmd\nc;d" @shell.should_receive(:cp_r).with "aDir/templates/a.template/run-endless.sh", "." @shell.should_receive(:file?).with("run-endless.sh").and_return true @shell.should_receive(:read_file).with("run-endless.sh").and_return "%rm% a\nb.%sh%\nc%:%d" @shell.should_receive(:write_file).with "run-endless.sh", "del a\nb.cmd\nc;d" @scaffolder.scaffold "a.template", 'myKata' end end

describe Scaffolder do it "generates the files and directories" do @shell.should_receive(:real_dir_entries).with("aDir/templates/a.template").and @shell.should_receive(:cp_r).with "aDir/templates/a.template/a", "." @shell.should_receive(:file?).with("a").and_return false @shell.should_receive(:cp_r).with "aDir/templates/a.template/b", "." @shell.should_receive(:file?).with("b").and_return false @scaffolder.generate "a.template", 'myKata' end end

describe Scaffolder do it "replaces placeholders" do @shell.should_receive(:real_dir_entries).with("aDir/templates/a.template").and @shell.should_receive(:cp_r).with "aDir/templates/a.template/a", "." @shell.should_receive(:file?).with("a").and_return false @shell.should_receive(:cp_r).with "aDir/templates/a.template/README", "." @shell.should_receive(:file?).with("README").and_return true @shell.should_receive(:read_file).with("README").and_return '%rm% %kata_file%\ @shell.should_receive(:write_file).with "README", 'del myKata\nb.cmd\nc;d' @shell.should_receive(:cp_r).with "aDir/templates/a.template/run-once.sh", "." @shell.should_receive(:file?).with("run-once.sh").and_return true @shell.should_receive(:read_file).with("run-once.sh").and_return "%rm% a\nb.%s @shell.should_receive(:write_file).with "run-once.sh", "del a\nb.cmd\nc;d" @shell.should_receive(:cp_r).with "aDir/templates/a.template/run-endless.sh", @shell.should_receive(:file?).with("run-endless.sh").and_return true @shell.should_receive(:read_file).with("run-endless.sh").and_return "%rm% a\nb @shell.should_receive(:write_file).with "run-endless.sh", "del a\nb.cmd\nc;d" @scaffolder.generate "a.template", 'myKata' end end

describe Scaffolder do before(:each) do @shell = mock @shell.should_receive(:shell_extension).any_number_of_times.and_return "cmd" @shell.should_receive(:remove_command_name).any_number_of_times.and_return "de @shell.should_receive(:path_separator).any_number_of_times.and_return ";" @shell.should_receive(:dir_separator).any_number_of_times.and_return "/" Scaffolder.should_receive(:current_file).any_number_of_times.and_return("aDir/ @scaffolder = Scaffolder.new @shell end end

ZOM G ......F...

<3

test all the things

30 assertions

30 assertions @shell.should_receive(:x)

30 assertions @shell.should_receive(:x) .with(y)

30 assertions @shell.should_receive(:x) .with(y) .and_return z

......... ......... ......... .........

unit tests 30 assertions 20 assertions 10 assertions 0 assertions

unit tests testing what, exactly?

@kata.generate README prime.rb run.sh ... ?

@kata.generate README prime.rb run.sh ...

magic happens here

@shell.should_receive(:real_dir_entries).with("aDir/ @shell.should_receive(:cp_r).with "aDir/templates/a. @shell.should_receive(:file?).with("a").and_return f @shell.should_receive(:cp_r).with "aDir/templates/a. @shell.should_receive(:file?).with("README").and_ret @shell.should_receive(:read_file).with("README").and @shell.should_receive(:write_file).with "README", 'd @shell.should_receive(:cp_r).with "aDir/templates/a. @shell.should_receive(:file?).with("run-once.sh").an @shell.should_receive(:read_file).with("run-once.sh" @shell.should_receive(:write_file).with "run-once.sh @shell.should_receive(:cp_r).with "aDir/templates/a. @shell.should_receive(:file?).with("run-endless.sh") @shell.should_receive(:read_file).with("run-endless. @shell.should_receive(:write_file).with "run-endless

delegation vs micro-management

unit tests have conceded defeat

describe Scaffolder do before (:each) do @shell = mock @shell.should_receive(:shell_extension).any_number_of_times.and_return "cmd" @shell.should_receive(:remove_command_name).any_number_of_times.and_return "del" @shell.should_receive(:path_separator).any_number_of_times.and_return ";" @shell.should_receive(:dir_separator).any_number_of_times.and_return "/" Scaffolder.should_receive(:current_file).any_number_of_times.and_return("aDir/lib/aFile.rb") @scaffolder = Scaffolder.new @shell end it "generates the files and directories" do @shell.should_receive(:real_dir_entries).with("aDir/templates/a.template").and_return ["a", "b"] @shell.should_receive(:cp_r).with "aDir/templates/a.template/a", "." @shell.should_receive(:file?).with("a").and_return false @shell.should_receive(:cp_r).with "aDir/templates/a.template/b", "." @shell.should_receive(:file?).with("b").and_return false @scaffolder.scaffold "a.template", 'myKata' end it "replaces placeholders" do @shell.should_receive(:real_dir_entries).with("aDir/templates/a.template").and_return ["a", "README", "run-once.sh", "run-endless.sh"] @shell.should_receive(:cp_r).with "aDir/templates/a.template/a", "." @shell.should_receive(:file?).with("a").and_return false @shell.should_receive(:cp_r).with "aDir/templates/a.template/README", "." @shell.should_receive(:file?).with("README").and_return true @shell.should_receive(:read_file).with("README").and_return '%rm% %kata_file%\nb.%sh%\nc%:%d' @shell.should_receive(:write_file).with "README", 'del myKata\nb.cmd\nc;d' @shell.should_receive(:cp_r).with "aDir/templates/a.template/run-once.sh", "." @shell.should_receive(:file?).with("run-once.sh").and_return true @shell.should_receive(:read_file).with("run-once.sh").and_return "%rm% a\nb.%sh%\nc%:%d" @shell.should_receive(:write_file).with "run-once.sh", "del a\nb.cmd\nc;d" @shell.should_receive(:cp_r).with "aDir/templates/a.template/run-endless.sh", "." @shell.should_receive(:file?).with("run-endless.sh").and_return true @shell.should_receive(:read_file).with("run-endless.sh").and_return "%rm% a\nb.%sh%\nc%:%d" @shell.should_receive(:write_file).with "run-endless.sh", "del a\nb.cmd\nc;d" @scaffolder.scaffold "a.template", 'myKata' end end

unit tests for the generated kata files

integration tests for the generated kata files

characterization

characterization run the code

characterization run the code make assertions about whatever happens

describe Scaffolder do end

describe Scaffolder do it "works" do scaffolder.generate('ruby.rspec', 'prime') end end

describe Scaffolder do let(:scaffolder) { } it "works" do scaffolder.generate('ruby.rspec', 'prime') end end

describe Scaffolder do let(:scaffolder) { Scaffolder.new } it "works" do scaffolder.generate('ruby.rspec', 'prime') end end

describe Scaffolder do let(:scaffolder) { Scaffolder.new(shell) } it "works" do scaffolder.generate('ruby.rspec', 'prime') end end

describe Scaffolder do let(:shell) { ShellWrapper.new } let(:scaffolder) { Scaffolder.new(shell) } it "works" do scaffolder.scaffold('ruby.rspec', 'prime') end end

No content

$ git status

$ git status # Untracked files: # #!.meta #!README #!prime.rb #!run-endless.sh #!run-once.sh

describe Scaffolder do let(:files) do [ '.meta', 'prime.rb', 'README', 'run-endless.sh', 'run-once.sh' ] end it "works"... end

describe Scaffolder do it "works" do scaffolder.scaffold('ruby.rspec', 'prime') expect(File.read('.meta')).to eq('...') expect(File.read('README')).to eq('...') # etc end end

describe Scaffolder do after(:each) do files.each do |file| FileUtils.rm_f(file) end end it "works" do # ... end end

Finished in 0.00632 seconds 1 example, 0 failures .

I’m no genius and so can you

reality vs fantasy

red flag time to refactor

the secret fate of a characterization test

confidence to refactor

decouple template source and kata destination

simplify the algorithm

spot the abstractions

a KataFile KataFile = Struct.new(:name, :contents)

kata a Translator template

a KataStore ./templates/ruby.rspec/* [kata_file1, kata_file2, ...] [kata_file1, kata_file2, ...] /tmp/*

or something like that

theory vs practice

clarity and chaos

Query Command Incoming Private Outgoing assert return value assert side effects do not assert do not assert do not assert assert message sent

F F F F F F F thank you <3 <3 <3 ......... c

Practical Object Oriented Design in Ruby Sandi Metz The Magic Tricks of Testing Sandi Metz Working Effectively with Legacy Code Michael Feathers CodersDojo Client FreeBSD License, (c) The CodersDojo Team Limited Red Joseph Wilk Fonts & Colors Damon Davison