Change behavior of should_not allow_value

Instead of asserting that any of the given value is an invalid value
(allowing good values to pass through), assert that *all* values are
invalid values (allowing good values not to pass through).

This means that this test which formerly passed now fails (assuming that
'good value' is a value that does not produce an invalid record):

    expect(record).not_to allow_value('good value', *bad_values)

NEWS.md

@@ -1,3 +1,15 @@
+# 3.0.0
+
+### Backward-incompatible changes
+
+* The negative form of `allow_value` has been changed so that instead of
+ asserting that any of the given values is an invalid value (allowing good
+ values to pass through), assert that *all* values are invalid values (allowing
+ good values not to pass through). This means that this test which formerly
+ passed will now fail:
+
+ expect(record).not_to allow_value('good value', *bad_values)
+
 # 2.8.0
 
 ### Deprecations

lib/shoulda/matchers/active_model/allow_value_matcher.rb

@@ -215,14 +215,12 @@ def _after_setting_value(&callback)
 
  def matches?(instance)
  self.instance = instance
- validator.record = instance
+ values_to_match.all? { |value| value_matches?(value) }
+ end
 
- values_to_match.none? do |value|
- validator.reset
- self.value = value
- set_attribute(value)
- errors_match? || any_range_error_occurred?
- end
+ def does_not_match?(instance)
+ self.instance = instance
+ values_to_match.all? { |value| !value_matches?(value) }
  end
 
  def failure_message
@@ -241,15 +239,26 @@ def description
 
  protected
 
- attr_reader :attribute_to_check_message_against
- attr_accessor :values_to_match, :instance, :attribute_to_set, :value,
+ attr_reader :instance, :attribute_to_check_message_against
+ attr_accessor :values_to_match, :attribute_to_set, :value,
  :matched_error, :after_setting_value_callback, :validator
 
+ def instance=(instance)
+ @instance = instance
+ validator.record = instance
+ end
+
  def attribute_to_check_message_against=(attribute)
  @attribute_to_check_message_against = attribute
  validator.attribute = attribute
  end
 
+ def value_matches?(value)
+ self.value = value
+ set_attribute(value)
+ !(errors_match? || any_range_error_occurred?)
+ end
+
  def set_attribute(value)
  set_attribute_ignoring_range_errors(value)
  after_setting_value_callback.call

spec/unit/shoulda/matchers/active_model/allow_value_matcher_spec.rb

@@ -165,24 +165,29 @@
  less_than_or_equal_to: 50000
  end.new
  end
+
  bad_values = [nil, '', 'abc', '0', '50001', '123456', []]
 
- it 'allows a good value' do
+ it 'matches given a good value' do
  expect(model).to allow_value('12345').for(:attr)
  end
 
- bad_values.each do |bad_value|
- it "rejects a bad value (#{bad_value.inspect})" do
+ it 'does not match given a bad value' do
+ bad_values.each do |bad_value|
  expect(model).not_to allow_value(bad_value).for(:attr)
  end
  end
 
- it "rejects several bad values (#{bad_values.map(&:inspect).join(', ')})" do
+ it 'does not match given multiple bad values' do
  expect(model).not_to allow_value(*bad_values).for(:attr)
  end
 
- it "rejects a mix of both good and bad values" do
- expect(model).not_to allow_value('12345', *bad_values).for(:attr)
+ it "does not match given good values along with bad values" do
+ message = %{Expected errors when attr is set to "12345",\ngot no errors}
+
+ expect {
+ expect(model).not_to allow_value('12345', *bad_values).for(:attr)
+ }.to fail_with_message(message)
  end
  end