Class: Fixpoint

Inherits:
Object
  • Object
show all
Defined in:
lib/fixpoint.rb

Overview

A fixpoint is a snapshot of the database contents. It is saved to the spec/fixpoints folder. A fixpoint (file) contains a mapping of table names to a list if their records.

Empty tables are stripped from files.

Make sure to run the tests in the right order: In a single RSpec file, you can use the order in which the tests are defined (‘RSpec.describe ’MyFeature’, order: :defined do`). However, tests in groups might follow a slightly different order (see relishapp.com/rspec/rspec-core/docs/configuration/overriding-global-ordering)

If you did a lot of changes to a test, you can remove a fixpoint file from its directory. It will be recreated when the test producing it runs again. Don’t forget re-running the tests _based on_ it because their fixpoints might have to change too. Example: You need to add something to the database’s seeds.rb. All subsequent fixpoints are missing the required entry. To update all fixpoints, just remove the whole ‘spec/fixpoints` folder and re-run all tests. Now all fixpoints should be updated. Be careful though, don’t just remove the fixpoints if you are not sure what is going on. A change in a fixpoint might point to an unintended change in code.

We need to be be careful to use let and let! with factories. Records might be created twice when using create in there (once by the fixpoint and once by the factory).

KNOWN ISSUES Under certain conditions you may get ‘duplicate key value violates unique constraint` because the primary key sequences are not updated correctly. If this happens, just add a Fixpoint.reset_pk_sequences! at the beginning of your test. We need to dig a little deeper here at some point…

LIMITATIONS The records in tables are ordered by their id. If there is no id for a table, we use database’s order (what the SELECT query returns). This order may be instable.

Direct Known Subclasses

IncrementalFixpoint

Defined Under Namespace

Classes: Error

Constant Summary collapse

FIXPOINT_FOLDER = 
'fixpoints'
TABLES_TO_SKIP = 
%w[ar_internal_metadata delayed_jobs schema_info schema_migrations].freeze

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(records_in_tables) ⇒ Fixpoint

Returns a new instance of Fixpoint.



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# File 'lib/fixpoint.rb', line 106

def initialize(records_in_tables)
  @records_in_tables = records_in_tables
end

Instance Attribute Details

#records_in_tables ⇒ Object (readonly)

the complete records in the tables



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# File 'lib/fixpoint.rb', line 104

def records_in_tables
  @records_in_tables
end

Class Method Details

.exists?(fixname) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/fixpoint.rb', line 36

def exists?(fixname)
  File.exist?(fixpoint_path(fixname))
end

.fixpoint_path(fixname) ⇒ Object

Raises:



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# File 'lib/fixpoint.rb', line 64

def fixpoint_path(fixname)
  fspath = self.fixpoints_path
  raise Fixpoint::Error, 'Can not automatically infer the base path for the specs, please set `rspec_config.fixpoints_path` explicitly' if fspath.nil?
  raise Fixpoint::Error, "Please create the fixpoints folder (and maybe create a .gitkeep): #{fspath}" if !File.exist?(fspath)

  File.join(fspath, "#{fixname}.yml")
end

.from_database(conn) ⇒ Object

Creates a Fixpoint from the database contents. Empty tables are skipped.



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# File 'lib/fixpoint.rb', line 48

def from_database(conn)
  new(read_database_records(conn))
end

.from_file(fixname) ⇒ Object

Raises:



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# File 'lib/fixpoint.rb', line 40

def from_file(fixname)
  raise Fixpoint::Error, "The requested fixpoint (\"#{fixname}\") could not be found. Re-run the test which stores the fixpoint." unless exists?(fixname)

  file_path = fixpoint_path(fixname)
  new(YAML.load_file(file_path))
end

.remove(fixname) ⇒ Object 



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# File 'lib/fixpoint.rb', line 52

def remove(fixname)
  FileUtils.rm_f(fixpoint_path(fixname))
end

.reset_pk_sequences!(conn) ⇒ Object

reset primary key sequences for all tables useful when tests sometimes run before the storing the first fixpoint. these test might have incremented the id sequence already, so the ids in the fixpoints chance (which leads to differences).



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# File 'lib/fixpoint.rb', line 59

def reset_pk_sequences!(conn)
  return unless conn.respond_to?(:reset_pk_sequence!)
  conn.tables.each { |table_name| conn.reset_pk_sequence!(table_name) }
end

Instance Method Details

#load_into_database(conn) ⇒ Object 



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# File 'lib/fixpoint.rb', line 110

def load_into_database(conn)
  # Here some more pointers on implementation details of fixtures:
  # - https://github.com/rails/rails/blob/2998672fc22f0d5e1a79a29ccb60d0d0e627a430/activerecord/lib/active_record/fixtures.rb#L612
  # - http://api.rubyonrails.org/v5.2.4/classes/ActiveRecord/FixtureSet.html#method-c-create_fixtures
  # - https://github.com/rails/rails/blob/67feba0c822d64741d574dfea808c1a2feedbcfc/activerecord/test/cases/fixtures_test.rb
  #
  # Note from the past (useful if we want to get back to using Rails' +create_fixtures+ method)
  # we used to do: ActiveRecord::FixtureSet.create_fixtures(folder_path, filename_without_extension) # this will also clear the table
  # but we abandoned this approach because we want to one file per fixpoint (not one file per table)
  # ActiveRecord::FixtureSet.reset_cache # create_fixtures does use only the table name as cache key. we always invalidate the cache because we may want to read different fixpoints but with the same table names

  # let's remove all data
  conn.tables.each { |table| conn.select_all("DELETE FROM #{conn.quote_table_name(table)}") }

  # actually insert
  conn.insert_fixtures_set(@records_in_tables)
  self.class.reset_pk_sequences!(conn)
end

#records_for_table(table_name, ignore_columns = []) ⇒ Object

Returns the records for the given table_name as a list of Hashes. ignore_columns array of columns to remove from each record Hash.

Aside from having the form <tt>[:created_at, :updated_at]</tt>,
it can contain attributes scoped by a table name <tt>[:created_at, :updated_at, users: [:password_hash]]</tt>



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# File 'lib/fixpoint.rb', line 143

def records_for_table(table_name, ignore_columns = [])
  strip_columns_from_records(@records_in_tables[table_name], table_name, ignore_columns)
end

#save_to_file(fixname) ⇒ Object 



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# File 'lib/fixpoint.rb', line 129

def save_to_file(fixname)
  file_path = self.class.fixpoint_path(fixname)
  FileUtils.mkdir_p(File.dirname(file_path))
  File.write(file_path, contents_for_file)
end

#table_names ⇒ Object 



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# File 'lib/fixpoint.rb', line 135

def table_names
  @records_in_tables.keys
end