Deep down fixtures

Slides for talk given at RubyKaigi 2014

Transcript

1. Deep Down Fixtures @_cha1tanya
2. /rubykaigi2014/speakers/prathamesh.yml prathamesh: company: BigBinary role: Software Engineer hometown: Pune, India ruby_group: pune.rb github: prathamesh-sonpatki twitter: _cha1tanya interestes: <%= %w(ruby rails cricket emacs) %>
3. /india/rubyconfs.yml rubyconfindia: website: rubyconfindia.org location: Goa..probably when: Around April 2015**
4. /india/rubyconfs.yml rubyconfindia: website: rubyconfindia.org location: Goa when: April 3rd and 4th 2015 ! garden_city_ruby_conf: website: gardencityruby.org location: Banglore when: 10 January 2015 cfp: will open soon.. ! deccan_ruby_conf: website: deccanrubyconf.org location: pune when: Around June/July 2015**
5. Why I want to talk about fixtures?
6. Why? • We should know the tool before rejecting it
7. Why? • We should know the tool before rejecting it • Fixtures are baked into Rails
8. Why? • We should know the tool before rejecting it • Fixtures are baked into Rails • Understanding what all things are possible with fixtures
9. Why? • We should know the tool before rejecting it • Fixtures are baked into Rails • Understanding what all things are possible with fixtures • Staying close to Rails stack
10. Fixtures are weird
11. What are fixtures? • YAML files(CSV)
12. What are fixtures?
13. What are fixtures? • YAML files(CSV) • Real • Multiple definitions for same object
14. Creating Fixtures
15. Creating fixtures • As simple as writing .yml files
16. Creating fixtures • As simple as writing .yml files • Needs thinking
17. Creating fixtures • As simple as writing .yml files • Needs thinking • Needs creativity
18. Creating fixtures • As simple as writing .yml files • Needs thinking • Needs creativity(to make them memorable)
19. Protip: Key matters • :admin_user • :driver • :monitor • :emergency_contact_for_john
20. Protip: Key matters repo1: user_name: rails name: rails full_name: rails/rails language: ruby created_at: 2012-11-10 21:50:48.351554000 Z updated_at: 2012-11-10 21:50:48.351554000 Z issues_count: 0
21. Protip: Key matters repo1: user_name: rails name: rails full_name: rails/rails language: ruby created_at: 2012-11-10 21:50:48.351554000 Z updated_at: 2012-11-10 21:50:48.351554000 Z issues_count: 0 repo = repos(:repo1)
22. Protip: Key matters repo1: user_name: rails name: rails full_name: rails/rails language: ruby created_at: 2012-11-10 21:50:48.351554000 Z updated_at: 2012-11-10 21:50:48.351554000 Z issues_count: 0 repo = repos(:repo1)
23. Protip: Key matters rails_rails: user_name: rails name: rails full_name: rails/rails language: ruby created_at: 2012-11-10 21:50:48.351554000 Z updated_at: 2012-11-10 21:50:48.351554000 Z issues_count: 0 repo = repos(:rails_rails)
24. Protip:Don’t specify ids** rails_rails: id: 1 user_name: rails name: rails full_name: rails/rails language: ruby created_at: 2012-11-10 21:50:48.351554000 Z updated_at: 2012-11-10 21:50:48.351554000 Z issues_count: 0
25. Protip:Don’t specify ids** • Rails will generate stable ids for you • Useful in defining associations
26. ProProtip:Listen to DHH
27. Protip: Don’t cover everything
28. https://twitter.com/ search?q=fixtures %20from%3Adhh
31. Loading Fixtures
32. Loading fixtures ! • Read from yaml file • Convert into hash • Delete all existing data
33. Loading fixtures • Delete all existing data
34. Loading fixtures • Delete all existing data Fixture Delete (0.3ms) DELETE FROM "issue_assignments" Fixture Delete (0.3ms) DELETE FROM "issues" Fixture Delete (0.3ms) DELETE FROM "repo_subscriptions" Fixture Delete (0.3ms) DELETE FROM "repos" Fixture Delete (0.7ms) DELETE FROM "users"
35. Loading fixtures • Delete all existing data • Load data
36. Loading fixtures • Delete all existing data • Load data Fixture Insert (0.2ms) INSERT INTO "repo_subscriptions" ("user_name", "repo_name", "created_at", "updated_at", "last_sent_at", "email_limit", "id", "repo_id", "user_id") VALUES ('rails', 'rails', '2013-10-29 21:09:48.351554', '2013-10-29 21:09:48.351554', NULL, 5, 836719243, 603590727, 110871456)
37. All data is loaded before test suite starts
38. Tests will run faster!
39. Loading fixtures • Fixtures are ActiveRecord objects
40. Loading fixtures user = users(:prathamesh) assert_empty user.repos
41. Loading fixtures • Fixtures are ActiveRecord objects**
42. Loading fixtures # /rails/activerecord/lib/active_record/connection_adapters/abstract/ database_statements.rb ! # Inserts the given fixture into the table. Overridden in adapters that # require something beyond a simple insert (eg. Oracle). def insert_fixture(fixture, table_name) columns = schema_cache.columns_hash(table_name) ! key_list = [] value_list = fixture.map do |name, value| key_list << quote_column_name(name) quote(value, columns[name]) end ! execute "INSERT INTO #{quote_table_name(table_name)} (#{key_list.join(', ')}) VALUES (#{value_list.join(', ')})", 'Fixture Insert' end
43. Loading fixtures • Fixtures are ActiveRecord objects • Callbacks and validations are skipped!
44. Accessing Fixtures
45. Accessing fixtures • Access from database • Dynamic method • Auto-instantiation
46. Accessing fixtures • Access from database repo = Repo.first
47. Accessing fixtures • Dynamic method repo = repos(:rails_rails)
48. Accessing fixtures • Auto-instantiation # /test/test_helper.rb class ActiveSupport::TestCase self.use_instantiated_fixtures = true end ! @repos[‘rails_rails']
49. Accessing fixtures • Auto-instantiation # /test/test_helper.rb class ActiveSupport::TestCase self.use_instantiated_fixtures = true end ! @repos[‘rails_rails’] @rails_rails !
50. Accessing fixtures • Auto-instantiation • Slow, memory consuming
51. Identifying fixtures • How repos(:rails_rails) works?
52. Identifying fixtures # Returns a consistent, platform-independent identifier for +label+. # Integer identifiers are values less than 2^30. UUIDs are RFC 4122 versio 5 SHA-1 hashes. def self.identify(label, column_type = :integer) if column_type == :uuid Digest::UUID.uuid_v5(Digest::UUID::OID_NAMESPACE, label.to_s) else Zlib.crc32(label.to_s) % MAX_ID end end
53. Associations
54. Associations • Label references if you don’t specify id
55. Associations schneems_to_triage: repo: issue_triage_sandbox user: schneems user_name: bemurphy repo_name: issue_triage_sandbox jroes_to_rails: repo: rails_rails user: jroes user_name: rails repo_name: rails !
56. Associations schneems_to_triage: repo: issue_triage_sandbox user: schneems user_name: bemurphy repo_name: issue_triage_sandbox jroes_to_rails: repo: rails_rails user: jroes user_name: rails repo_name: rails !
57. Now lets learn some トリック
58. Setting a value to nil • A column with default value, but you need NULL • Many ways to do it
59. Setting a value to nil irb(main):001:0> require 'yaml' => true irb(main):002:0> YAML.load("--- \n:k: null\n") => {:k=>nil}
60. Setting a value to nil jroes_to_rails: repo: rails_rails user: jroes user_name: rails repo_name: rails created_at: 2013-10-29 21:09:48.351554000 Z updated_at: 2013-10-29 21:09:48.351554000 Z last_sent_at: NULL 60
61. Setting a value to nil irb(main):001:0> require 'yaml' => true irb(main):002:0> YAML.load("--- \n:k: \n") => {:k=>nil} irb(main):003:0>
62. Setting a value to nil jroes_to_rails: repo: rails_rails user: jroes user_name: rails repo_name: rails created_at: 2013-10-29 21:09:48.351554000 Z updated_at: 2013-10-29 21:09:48.351554000 Z last_sent_at:
63. ERBin it up • Need to generate dynamic data • Sprinkle ERB in yaml files
64. ERBin it up prathamesh: github: prathamesh-sonpatki private: false last_clicked_at: <%= Time.now %>
65. ERBin it up <% 1.upto(1000) do |i| %> issue_<%= i %>: name: rails_<%= i %> <% end %>
66. ERBin it up • Need to generate dynamic data • Sprinkle ERB in yaml files • Use with caution
67. Timestamps • Autofills standard timestamp columns if they are not present in fixture
68. Timestamps • Autofills standard timestamp columns if they are not present in fixture • Works only if model.record_timestamps is true(default is true)
69. Timestamps # /rails/activerecord/lib/active_record/fixtures.rb ! now = config.default_timezone == :utc ? Time.now.utc : Time.now now = now.to_s(:db) ! if model_class.record_timestamps timestamp_column_names.each do |c_name| row[c_name] = now unless row.key?(c_name) end end
70. Timestamps # /rails/activerecord/lib/active_record/fixtures.rb ! now = config.default_timezone == :utc ? Time.now.utc : Time.now now = now.to_s(:db) ! if model_class.record_timestamps timestamp_column_names.each do |c_name| row[c_name] = now unless row.key?(c_name) end end
71. Timestamps • Autofills standard timestamp columns if they are not present in fixture • Works only if model.record_timestamps is true(default is true) • created_at, updated_at, created_on, updated_on
72. DRYing up fixtures
73. Label Interpolation schneems: github: schneems ! jroes: github: jroes
74. Label Interpolation schneems: github:$LABEL ! jroes: github:$LABEL
75. Label Interpolation schneems: github:$LABEL email: $LABEL@example.com ! jroes: github:$LABEL email: $LABEL@example.com https://github.com/rails/rails/pull/14399
76. Label Interpolation # /rails/activerecord/lib/active_record/fixtures.rb ! # interpolate the fixture label row.each do |key, value| row[key] = value.gsub("$LABEL", label) if value.is_a? (String) end ! !
77. Database tricks** prathamesh: github: prathamesh-sonpatki private: false last_clicked_at: <%= Time.now %>
78. Database tricks** prathamesh: github: prathamesh-sonpatki private: false last_clicked_at: now
79. Database tricks** INSERT INTO "users" ("github", "private", “last_clicked_at”, ”id") VALUES (‘prathamesh-sonpatki', 't', ‘now',1144934)
80. Database tricks** ! • now is special value in PostGreSQL • Shorthand that will be converted to date/time when read. • http://www.postgresql.org/docs/9.3/static/datatype- datetime.html#AEN5861
81. YAML Defaults issue_triage_sandbox: user_name: bemurphy name: issue_triage_sandbox full_name: bemurphy/issue_triage_sandbox language: ruby created_at: 2012-11-10 21:50:48.351554000 Z updated_at: 2012-11-10 21:50:48.351554000 Z issues_count: 1 ! rails_rails: user_name: rails name: rails full_name: rails/rails language: ruby created_at: 2012-11-10 21:50:48.351554000 Z updated_at: 2012-11-10 21:50:48.351554000 Z issues_count: 0
82. YAML Defaults issue_triage_sandbox: user_name: bemurphy name: issue_triage_sandbox full_name: bemurphy/issue_triage_sandbox language: ruby created_at: 2012-11-10 21:50:48.351554000 Z updated_at: 2012-11-10 21:50:48.351554000 Z issues_count: 1 ! rails_rails: user_name: rails name: rails full_name: rails/rails language: ruby created_at: 2012-11-10 21:50:48.351554000 Z updated_at: 2012-11-10 21:50:48.351554000 Z issues_count: 0
83. YAML Defaults DEFAULTS: &DEFAULTS language: ruby created_at: 2012-11-10 21:50:48.351554000 Z updated_at: 2012-11-10 21:50:48.351554000 Z ! issue_triage_sandbox: user_name: bemurphy name: issue_triage_sandbox full_name: bemurphy/issue_triage_sandbox <<: *DEFAULTS issues_count: 1 ! rails_rails: user_name: rails name: rails full_name: rails/rails <<: *DEFAULTS issues_count: 0
84. Some moar advanced stuff
85. Ordered fixtures • By default fixtures are unordered • But sometimes, order is required • For eg. fork of a repo. Parent repo is needed before the repo can be forked.
86. Ordered fixtures rails_rails: id: 1 user_name: rails name: rails full_name: rails/rails language: ruby created_at: 2012-11-10 21:50:48.351554000 Z updated_at: 2012-11-10 21:50:48.351554000 Z issues_count: 0 parent_repo_id:
87. Ordered fixtures prathamesh_rails: id: 2 user_name: prathamesh-sonpatki name: rails full_name: prathamesh-sonpatki/rails language: ruby created_at: 2012-11-10 21:50:48.351554000 Z updated_at: 2012-11-10 21:50:48.351554000 Z issues_count: 0 parent_repo_id: 1
88. Ordered fixtures • OMAP YAML • http://yaml.org/type/omap.html
89. Ordered fixtures • OMAP YAML --- !omap - rails_rails: id: 1 user_name: rails name: rails full_name: rails/rails ! - prathamesh_rails: id: 2 user_name: prathamesh-sonpatki name: rails full_name: prathamesh-sonpatki/rails
90. Table name != Model name • Legacy table • Namespaced fixtures • Namespaced models
91. Table name != Model name • set_fixture_class method • class method • accepts hash of filenames with key and class name as value • key should be name of fixture(or relative path) • value should be name of class
92. Table name != Model name • Legacy table self.set_fixture_class old_issues: LegacyIssue
93. Table name != Model name • Namespaced fixtures self.set_fixture_class '/legacy/issues' => LegacyIssue
94. Table name != Model name • Namespaced models self.set_fixture_class 'legacy_issues' => Legacy::Issue
95. https://github.com/rails/rails/issues/16831
96. Fixtures work!
97. ありがとうございます！ @_cha1tanya
98. Credits • https://www.flickr.com/photos/raffacama/ 15001944068/ • http://www.deviantart.com/art/ready-to- jump-133369508 • https://whatdoitest.com/