ruby - 当 block 内的断言失败时，Minitest 报告错误的行号

Question

我已经编写了一个断言，用于收集在生成 block 时创建的新记录。这是一个示例，该 block 中有一个失败的断言:

  product =
    assert_latest_record Product do  #  line 337
      post :create, 
           :product => { ... }
      assert false  #  line 340
    end

我断言的来源如下，但我认为它不相关。它不会拦截 Minitest 异常，甚至不会调用 rescue 或 ensure。

问题是当该 block 内的断言失败时。故障诊断消息报告行号为 337 的外部断言行，而不是 340，即失败的内部断言行。这一点很重要，例如，如果我的同事编写了一个包含太多行的运行测试；隔离故障线路变得更加困难。

为什么 Minitest 没有报告正确的行号？

---

来源:

##
# When a test case calls methods that write new ActiveModel records to a database,
# sometimes the test needs to assert those records were created, by fetching them back
# for inspection. +assert_latest_record+ collects every record in the given model or
# models that appear while its block runs, and returns either a single record or a ragged
# array.
#
# ==== Parameters
#
# * +models+ - At least 1 ActiveRecord model or association.
# * +message+ - Optional string or ->{block} to provide more diagnostics at failure time.
# * <code>&block</code> - Required block to call and monitor for new records.
#
# ==== Example
#
#   user, email_addresses =
#     assert_latest_record User, EmailAddress, ->{ 'Need moar records!' } do
#       post :create, ...
#     end
#   assert_equal 'franklyn', user.login  #  1 user, so not an array
#   assert_equal 2, email_addresses.size
#   assert_equal 'franklyn@gmail.com', email_addresses.first.mail
#   assert_equal 'franklyn@hotmail.com', email_addresses.second.mail
#
# ==== Returns
#
# The returned value is a set of one or more created records. The set is normalized,
# so all arrays of one item are replaced with the item itself.
#
# ==== Operations
#
# The last argument to +assert_latest_record+ can be a string or a callable block.
# At failure time the assertion adds this string or this block's return value to
# the diagnostic message.
#
# You may call +assert_latest_record+ with anything that responds to <code>.pluck(:id)</code>
# and <code>.where()</code>, including ActiveRecord associations:
#
#   user = User.last
#   email_address =
#     assert_latest_record user.email_addresses do
#       post :add_email_address, user_id: user.id, ...
#     end
#   assert_equal 'franklyn@philly.com', email_address.mail
#   assert_equal email_address.user_id, user.id, 'This assertion is redundant.'
#
def assert_latest_record(*models, &block)
  models, message = _get_latest_record_args(models, 'assert')
  latests = _get_latest_record(models, block)
  latests.include?(nil) and _flunk_latest_record(models, latests, message, true)
  pass  #  Increment the test runner's assertion count
  return latests.size > 1 ? latests : latests.first
end

##
# When a test case calls methods that might write new ActiveModel records to a
# database, sometimes the test must check that no records were written.
# +refute_latest_record+ watches for new records in the given class or classes
# that appear while its block runs, and fails if any appear.
#
# ==== Parameters
#
# See +assert_latest_record+.
#
# ==== Operations
#
#   refute_latest_record User, EmailAddress, ->{ 'GET should not create records' } do
#     get :index
#   end
#
# The last argument to +refute_latest_record+ can be a string or a callable block.
# At failure time the assertion adds this string or this block's return value to
# the diagnostic message.
#
# Like +assert_latest_record+, you may call +refute_latest_record+ with anything
# that responds to <code>pluck(:id)</code> and <code>where()</code>, including
# ActiveRecord associations.
#
def refute_latest_record(*models, &block)
  models, message = _get_latest_record_args(models, 'refute')
  latests = _get_latest_record(models, block)
  latests.all?(&:nil?) or _flunk_latest_record(models, latests, message, false)
  pass
  return
end

##
# Sometimes a test must detect new records without using an assertion that passes
# judgment on whether they should have been written. Call +get_latest_record+ to
# return a ragged array of records created during its block, or +nil+:
#
#   user, email_addresses, posts =
#     get_latest_record User, EmailAddress, Post do
#       post :create, ...
#     end
#
#   assert_nil posts, "Don't create Post records while creating a User"
#
# Unlike +assert_latest_record+, +get_latest_record+ does not take a +message+ string
# or block, because it has no diagnostic message.
#
# Like +assert_latest_record+, you may call +get_latest_record+ with anything
# that responds to <code>.pluck(:id)</code> and <code>.where()</code>, including
# ActiveRecord associations.
#
def get_latest_record(*models, &block)
  assert models.any?, 'Call get_latest_record with one or more ActiveRecord models or associations.'
  refute_nil block, 'Call get_latest_record with a block.'
  records = _get_latest_record(models, block)
  return records.size > 1 ? records : records.first
end  #  Methods should be easy to use correctly and hard to use incorrectly...

def _get_latest_record_args(models, what) #:nodoc:
  message = nil
  message = models.pop unless models.last.respond_to?(:pluck)
  valid_message = message.nil? || message.kind_of?(String) || message.respond_to?(:call)
  models.length > 0 && valid_message and return models, message

  raise "call #{what}_latest_record(models..., message) with any number\n" +
        'of Model classes or associations, followed by an optional diagnostic message'
end
private :_get_latest_record_args

def _get_latest_record(models, block) #:nodoc:
  id_sets = models.map{ |model| model.pluck(*model.primary_key) }  #  Sorry about your memory!
  block.call
  record_sets = []

  models.each_with_index do |model, index|
    pk = model.primary_key
    set = id_sets[index]

    records =
      if set.length == 0
        model
      elsif pk.is_a?(Array)
        pks = pk.map{ |k| "`#{k}` = ?" }.join(' AND ')
        pks = [ "(#{pks})" ] * set.length
        pks = pks.join(' OR ')
        model.where.not(pks, *set.flatten)
      else
        model.where.not(pk => set)
      end

    records = records.order(pk).to_a
    record_sets.push records.size > 1 ? records : records.first
  end

  return record_sets
end
private :_get_latest_record

def _flunk_latest_record(models, latests, message, polarity) #:nodoc:
  itch_list = []

  models.each_with_index do |model, index|
    records_found = latests[index] != nil
    records_found == polarity or itch_list << model.name
  end

  itch_list = itch_list.join(', ')
  diagnostic = "should#{' not' unless polarity} create new #{itch_list} record(s) in block"
  message = nil if message == ''
  message = message.call.to_s if message.respond_to?(:call)
  message = [ message, diagnostic ].compact.join("\n")
  raise Minitest::Assertion, message
end
private :_flunk_latest_record

Answer 1

您可以尝试将其配置为在 test_helper.rb 中记录异常:

def MiniTest.filter_backtrace(backtrace)
  backtrace
end

我不确定这是否是默认设置，但根据您的配置，可能不会显示回溯。