diff --git a/lib/active_storage_validations/matchers/aspect_ratio_validator_matcher.rb b/lib/active_storage_validations/matchers/aspect_ratio_validator_matcher.rb
index 3c4f78bf..90ae0ed7 100644
--- a/lib/active_storage_validations/matchers/aspect_ratio_validator_matcher.rb
+++ b/lib/active_storage_validations/matchers/aspect_ratio_validator_matcher.rb
@@ -4,6 +4,7 @@
 require_relative 'concerns/allow_blankable.rb'
 require_relative 'concerns/contextable.rb'
 require_relative 'concerns/messageable.rb'
+require_relative 'concerns/rspecable.rb'
 require_relative 'concerns/validatable.rb'
 
 module ActiveStorageValidations
@@ -17,6 +18,7 @@ class AspectRatioValidatorMatcher
       include AllowBlankable
       include Contextable
       include Messageable
+      include Rspecable
       include Validatable
 
       def initialize(attribute_name)
@@ -25,7 +27,11 @@ def initialize(attribute_name)
       end
 
       def description
-        "validate the aspect ratios allowed on attachment #{@attribute_name}."
+        "validate the aspect ratios allowed on :#{@attribute_name}."
+      end
+
+      def failure_message
+        "is expected to validate aspect ratio of :#{@attribute_name}"
       end
 
       def allowing(*aspect_ratios)
@@ -49,10 +55,6 @@ def matches?(subject)
           all_rejected_aspect_ratios_rejected?
       end
 
-      def failure_message
-        "is expected to validate aspect ratio of #{@attribute_name}"
-      end
-
       protected
 
       def all_allowed_aspect_ratios_allowed?
diff --git a/lib/active_storage_validations/matchers/attached_validator_matcher.rb b/lib/active_storage_validations/matchers/attached_validator_matcher.rb
index 50cbed79..ea6c029a 100644
--- a/lib/active_storage_validations/matchers/attached_validator_matcher.rb
+++ b/lib/active_storage_validations/matchers/attached_validator_matcher.rb
@@ -3,6 +3,7 @@
 require_relative 'concerns/active_storageable.rb'
 require_relative 'concerns/contextable.rb'
 require_relative 'concerns/messageable.rb'
+require_relative 'concerns/rspecable.rb'
 require_relative 'concerns/validatable.rb'
 
 module ActiveStorageValidations
@@ -15,6 +16,7 @@ class AttachedValidatorMatcher
       include ActiveStorageable
       include Contextable
       include Messageable
+      include Rspecable
       include Validatable
 
       def initialize(attribute_name)
@@ -22,7 +24,11 @@ def initialize(attribute_name)
       end
 
       def description
-        "validate #{@attribute_name} must be attached"
+        "validate that :#{@attribute_name} must be attached"
+      end
+
+      def failure_message
+        "is expected to validate attachment of :#{@attribute_name}"
       end
 
       def matches?(subject)
@@ -35,14 +41,6 @@ def matches?(subject)
           is_invalid_when_file_not_attached?
       end
 
-      def failure_message
-        "is expected to validate attached of #{@attribute_name}"
-      end
-
-      def failure_message_when_negated
-        "is expected to not validate attached of #{@attribute_name}"
-      end
-
       private
 
       def is_valid_when_file_attached?
diff --git a/lib/active_storage_validations/matchers/concerns/rspecable.rb b/lib/active_storage_validations/matchers/concerns/rspecable.rb
new file mode 100644
index 00000000..fd4ce5f9
--- /dev/null
+++ b/lib/active_storage_validations/matchers/concerns/rspecable.rb
@@ -0,0 +1,26 @@
+require "active_support/concern"
+
+module ActiveStorageValidations
+  module Matchers
+    module Rspecable
+      extend ActiveSupport::Concern
+
+      def initialize(attribute_name)
+        super
+        @failure_message_artefacts = []
+      end
+
+      def description
+        raise NotImplementedError, "#{self.class} did not define #{__method__}"
+      end
+
+      def failure_message
+        raise NotImplementedError, "#{self.class} did not define #{__method__}"
+      end
+
+      def failure_message_when_negated
+        failure_message.sub(/is expected to validate/, 'is expected not to validate')
+      end
+    end
+  end
+end
diff --git a/lib/active_storage_validations/matchers/content_type_validator_matcher.rb b/lib/active_storage_validations/matchers/content_type_validator_matcher.rb
index abcb2578..fdbf15e4 100644
--- a/lib/active_storage_validations/matchers/content_type_validator_matcher.rb
+++ b/lib/active_storage_validations/matchers/content_type_validator_matcher.rb
@@ -7,6 +7,7 @@
 require_relative 'concerns/allow_blankable.rb'
 require_relative 'concerns/contextable.rb'
 require_relative 'concerns/messageable.rb'
+require_relative 'concerns/rspecable.rb'
 require_relative 'concerns/validatable.rb'
 
 module ActiveStorageValidations
@@ -20,6 +21,7 @@ class ContentTypeValidatorMatcher
       include AllowBlankable
       include Contextable
       include Messageable
+      include Rspecable
       include Validatable
 
       def initialize(attribute_name)
@@ -28,7 +30,33 @@ def initialize(attribute_name)
       end
 
       def description
-        "validate the content types allowed on attachment #{@attribute_name}"
+        "validate the content types allowed on :#{@attribute_name}"
+      end
+
+      def failure_message
+        message = ["is expected to validate the content types of :#{@attribute_name}"]
+        build_failure_message(message)
+        message.join("\n")
+      end
+
+      def build_failure_message(message)
+        if @allowed_types_not_allowed.present?
+          message << "  the following content type#{'s' if @allowed_types.count > 1} should be allowed: :#{@allowed_types.join(", :")}"
+          message << "  but #{pluralize(@allowed_types_not_allowed)} rejected"
+        end
+
+        if @rejected_types_not_rejected.present?
+          message << "  the following content type#{'s' if @rejected_types.count > 1} should be rejected: :#{@rejected_types.join(", :")}"
+          message << "  but #{pluralize(@rejected_types_not_rejected)} accepted"
+        end
+      end
+
+      def pluralize(types)
+        if types.count == 1
+          ":#{types[0]} was"
+        else
+          ":#{types.join(", :")} were"
+        end
       end
 
       def allowing(*types)
@@ -52,22 +80,6 @@ def matches?(subject)
           all_rejected_types_rejected?
       end
 
-      def failure_message
-        message = ["Expected #{@attribute_name}"]
-
-        if @allowed_types_not_allowed.present?
-          message << "Accept content types: #{@allowed_types.join(", ")}"
-          message << "#{@allowed_types_not_allowed.join(", ")} were rejected"
-        end
-
-        if @rejected_types_not_rejected.present?
-          message << "Reject content types: #{@rejected_types.join(", ")}"
-          message << "#{@rejected_types_not_rejected.join(", ")} were accepted"
-        end
-
-        message.join("\n")
-      end
-
       protected
 
       def all_allowed_types_allowed?
diff --git a/lib/active_storage_validations/matchers/dimension_validator_matcher.rb b/lib/active_storage_validations/matchers/dimension_validator_matcher.rb
index 77c06cfd..fa2cc068 100644
--- a/lib/active_storage_validations/matchers/dimension_validator_matcher.rb
+++ b/lib/active_storage_validations/matchers/dimension_validator_matcher.rb
@@ -4,6 +4,7 @@
 require_relative 'concerns/allow_blankable.rb'
 require_relative 'concerns/contextable.rb'
 require_relative 'concerns/messageable.rb'
+require_relative 'concerns/rspecable.rb'
 require_relative 'concerns/validatable.rb'
 
 module ActiveStorageValidations
@@ -17,15 +18,38 @@ class DimensionValidatorMatcher
       include AllowBlankable
       include Contextable
       include Messageable
+      include Rspecable
       include Validatable
 
       def initialize(attribute_name)
         @attribute_name = attribute_name
         @width_min = @width_max = @height_min = @height_max = nil
+        @failure_message_artefacts = []
       end
 
       def description
-        "validate image dimensions of #{@attribute_name}"
+        "validate the image dimensions of :#{@attribute_name}"
+      end
+
+      def failure_message
+        message = ["is expected to validate dimensions of :#{@attribute_name}"]
+        build_failure_message(message)
+        message.join("\n")
+      end
+
+      def build_failure_message(message)
+        return unless @failure_message_artefacts.present?
+
+        message << "  but there seem to have issues with the matcher methods you used, since:"
+        @failure_message_artefacts.each do |error_case|
+          message << "  validation failed when provided with a #{error_case[:width]}x#{error_case[:height]}px test image"
+        end
+        message << "  whereas it should have passed"
+      end
+
+      def width(width)
+        @width_min = @width_max = width
+        self
       end
 
       def width_min(width)
@@ -38,8 +62,13 @@ def width_max(width)
         self
       end
 
-      def width(width)
-        @width_min = @width_max = width
+      def width_between(range)
+        @width_min, @width_max = range.first, range.last
+        self
+      end
+
+      def height(height)
+        @height_min = @height_max = height
         self
       end
 
@@ -53,21 +82,11 @@ def height_max(height)
         self
       end
 
-      def width_between(range)
-        @width_min, @width_max = range.first, range.last
-        self
-      end
-
       def height_between(range)
         @height_min, @height_max = range.first, range.last
         self
       end
 
-      def height(height)
-        @height_min = @height_max = height
-        self
-      end
-
       def matches?(subject)
         @subject = subject.is_a?(Class) ? subject.new : subject
 
@@ -87,14 +106,6 @@ def matches?(subject)
           height_equals?
       end
 
-      def failure_message
-        <<~MESSAGE
-          is expected to validate dimensions of #{@attribute_name}
-            width between #{@width_min} and #{@width_max}
-            height between #{@height_min} and #{@height_max}
-        MESSAGE
-      end
-
       protected
 
       def valid_width
@@ -106,52 +117,57 @@ def valid_height
       end
 
       def width_not_smaller_than_min?
-        @width_min.nil? || !passes_validation_with_dimensions(@width_min - 1, valid_height, 'width')
+        @width_min.nil? || !passes_validation_with_dimensions(@width_min - 1, valid_height)
       end
 
       def width_larger_than_min?
-        @width_min.nil? || @width_min == @width_max || passes_validation_with_dimensions(@width_min + 1, valid_height, 'width')
+        @width_min.nil? || @width_min == @width_max || passes_validation_with_dimensions(@width_min + 1, valid_height)
       end
 
       def width_smaller_than_max?
-        @width_max.nil? || @width_min == @width_max || passes_validation_with_dimensions(@width_max - 1, valid_height, 'width')
+        @width_max.nil? || @width_min == @width_max || passes_validation_with_dimensions(@width_max - 1, valid_height)
       end
 
       def width_not_larger_than_max?
-        @width_max.nil? || !passes_validation_with_dimensions(@width_max + 1, valid_height, 'width')
+        @width_max.nil? || !passes_validation_with_dimensions(@width_max + 1, valid_height)
       end
 
       def width_equals?
-        @width_min.nil? || @width_min != @width_max || passes_validation_with_dimensions(@width_min, valid_height, 'width')
+        @width_min.nil? || @width_min != @width_max || passes_validation_with_dimensions(@width_min, valid_height)
       end
 
       def height_not_smaller_than_min?
-        @height_min.nil? || !passes_validation_with_dimensions(valid_width, @height_min - 1, 'height')
+        @height_min.nil? || !passes_validation_with_dimensions(valid_width, @height_min - 1)
       end
 
       def height_larger_than_min?
-        @height_min.nil? || @height_min == @height_max || passes_validation_with_dimensions(valid_width, @height_min + 1, 'height')
+        @height_min.nil? || @height_min == @height_max || passes_validation_with_dimensions(valid_width, @height_min + 1)
       end
 
       def height_smaller_than_max?
-        @height_max.nil? || @height_min == @height_max || passes_validation_with_dimensions(valid_width, @height_max - 1, 'height')
+        @height_max.nil? || @height_min == @height_max || passes_validation_with_dimensions(valid_width, @height_max - 1)
       end
 
       def height_not_larger_than_max?
-        @height_max.nil? || !passes_validation_with_dimensions(valid_width, @height_max + 1, 'height')
+        @height_max.nil? || !passes_validation_with_dimensions(valid_width, @height_max + 1)
       end
 
       def height_equals?
-        @height_min.nil? || @height_min != @height_max || passes_validation_with_dimensions(valid_width, @height_min, 'height')
+        @height_min.nil? || @height_min != @height_max || passes_validation_with_dimensions(valid_width, @height_min)
       end
 
-      def passes_validation_with_dimensions(width, height, check)
+      def passes_validation_with_dimensions(width, height)
         mock_dimensions_for(attach_file, width, height) do
           validate
-          is_valid?
+          is_valid? || add_failure_message_artefact(width, height)
         end
       end
 
+      def add_failure_message_artefact(width, height)
+        @failure_message_artefacts << { width: width, height: height }
+        false
+      end
+
       def is_custom_message_valid?
         return true unless @custom_message
 
diff --git a/lib/active_storage_validations/matchers/size_validator_matcher.rb b/lib/active_storage_validations/matchers/size_validator_matcher.rb
index c70e1bea..e0f45a9a 100644
--- a/lib/active_storage_validations/matchers/size_validator_matcher.rb
+++ b/lib/active_storage_validations/matchers/size_validator_matcher.rb
@@ -7,6 +7,7 @@
 require_relative 'concerns/allow_blankable.rb'
 require_relative 'concerns/contextable.rb'
 require_relative 'concerns/messageable.rb'
+require_relative 'concerns/rspecable.rb'
 require_relative 'concerns/validatable.rb'
 
 module ActiveStorageValidations
@@ -20,15 +21,33 @@ class SizeValidatorMatcher
       include AllowBlankable
       include Contextable
       include Messageable
+      include Rspecable
       include Validatable
 
       def initialize(attribute_name)
         @attribute_name = attribute_name
         @min = @max = nil
+        @failure_message_artefacts = []
       end
 
       def description
-        "validate file size of #{@attribute_name}"
+        "validate file size of :#{@attribute_name}"
+      end
+
+      def failure_message
+        message = ["is expected to validate file size of :#{@attribute_name}"]
+        build_failure_message(message)
+        message.join("\n")
+      end
+
+      def build_failure_message(message)
+        return unless @failure_message_artefacts.present?
+
+        message << "  but there seem to have issues with the matcher methods you used, since:"
+        @failure_message_artefacts.each do |error_case|
+          message << "  validation failed when provided with a #{error_case[:size]} bytes test file"
+        end
+        message << "  whereas it should have passed"
       end
 
       def less_than(size)
@@ -69,14 +88,6 @@ def matches?(subject)
           not_higher_than_max?
       end
 
-      def failure_message
-        "is expected to validate file size of #{@attribute_name} to be between #{@min} and #{@max} bytes"
-      end
-
-      def failure_message_when_negated
-        "is expected to not validate file size of #{@attribute_name} to be between #{@min} and #{@max} bytes"
-      end
-
       protected
 
       def not_lower_than_min?
@@ -99,10 +110,15 @@ def passes_validation_with_size(size)
         mock_size_for(io, size) do
           attach_file
           validate
-          is_valid?
+          is_valid? || add_failure_message_artefact(size)
         end
       end
 
+      def add_failure_message_artefact(size)
+        @failure_message_artefacts << { size: size }
+        false
+      end
+
       def is_custom_message_valid?
         return true unless @custom_message
 
diff --git a/test/dummy/app/models/aspect_ratio/matcher.rb b/test/dummy/app/models/aspect_ratio/matcher.rb
index 0832d0b8..1cb98dc3 100644
--- a/test/dummy/app/models/aspect_ratio/matcher.rb
+++ b/test/dummy/app/models/aspect_ratio/matcher.rb
@@ -32,6 +32,11 @@ class AspectRatio::Matcher < ApplicationRecord
   has_one_attached :as_instance
   validates :as_instance, aspect_ratio: :square
 
+  has_one_attached :failure_message
+  validates :failure_message, aspect_ratio: :square
+  has_one_attached :failure_message_when_negated
+  validates :failure_message_when_negated, aspect_ratio: :square
+
   # Combinations
   has_one_attached :allowing_one_with_message
   validates :allowing_one_with_message, aspect_ratio: { with: :portrait, message: 'Not authorized aspect ratio.' }
diff --git a/test/dummy/app/models/attached/matcher.rb b/test/dummy/app/models/attached/matcher.rb
index 25657ec5..77be774e 100644
--- a/test/dummy/app/models/attached/matcher.rb
+++ b/test/dummy/app/models/attached/matcher.rb
@@ -25,5 +25,10 @@ class Attached::Matcher < ApplicationRecord
   has_one_attached :as_instance
   validates :as_instance, attached: true
 
+  has_one_attached :failure_message
+  validates :failure_message, attached: true
+  has_one_attached :failure_message_when_negated
+  validates :failure_message_when_negated, attached: true
+
   has_one_attached :not_required
 end
diff --git a/test/dummy/app/models/content_type/matcher.rb b/test/dummy/app/models/content_type/matcher.rb
index 94eab6d7..413e545a 100644
--- a/test/dummy/app/models/content_type/matcher.rb
+++ b/test/dummy/app/models/content_type/matcher.rb
@@ -32,6 +32,11 @@ class ContentType::Matcher < ApplicationRecord
   has_one_attached :as_instance
   validates :as_instance, content_type: :png
 
+  has_one_attached :failure_message
+  validates :failure_message, content_type: :png
+  has_one_attached :failure_message_when_negated
+  validates :failure_message_when_negated, content_type: :png
+
   # Combinations
   has_one_attached :allowing_one_with_message
   validates :allowing_one_with_message, content_type: { in: ['file/pdf'], message: 'Not authorized file type.' }
diff --git a/test/dummy/app/models/dimension/matcher.rb b/test/dummy/app/models/dimension/matcher.rb
index bcf9e4af..268ae444 100644
--- a/test/dummy/app/models/dimension/matcher.rb
+++ b/test/dummy/app/models/dimension/matcher.rb
@@ -57,6 +57,11 @@ class Dimension::Matcher < ApplicationRecord
   has_one_attached :as_instance
   validates :as_instance, dimension: { width: 150, height: 150 }
 
+  has_one_attached :failure_message
+  validates :failure_message, dimension: { width: 150, height: 150 }
+  has_one_attached :failure_message_when_negated
+  validates :failure_message_when_negated, dimension: { width: 150, height: 150 }
+
   # Combinations
   has_one_attached :width_and_height_exact
   has_one_attached :width_and_height_exact_with_message
diff --git a/test/dummy/app/models/size/matcher.rb b/test/dummy/app/models/size/matcher.rb
index 9b0387a0..376490ef 100644
--- a/test/dummy/app/models/size/matcher.rb
+++ b/test/dummy/app/models/size/matcher.rb
@@ -47,6 +47,11 @@ class Size::Matcher < ApplicationRecord
   has_one_attached :as_instance
   validates :as_instance, size: { less_than_or_equal_to: 5.megabytes }
 
+  has_one_attached :failure_message
+  validates :failure_message, size: { less_than_or_equal_to: 5.megabytes }
+  has_one_attached :failure_message_when_negated
+  validates :failure_message_when_negated, size: { less_than_or_equal_to: 5.megabytes }
+
   # Combinations
   has_one_attached :less_than_with_message
   has_one_attached :less_than_or_equal_to_with_message
diff --git a/test/matchers/aspect_ratio_validator_matcher_test.rb b/test/matchers/aspect_ratio_validator_matcher_test.rb
index 99c2c23d..9128b67b 100644
--- a/test/matchers/aspect_ratio_validator_matcher_test.rb
+++ b/test/matchers/aspect_ratio_validator_matcher_test.rb
@@ -2,6 +2,7 @@
 
 require 'test_helper'
 require 'matchers/shared_examples/checks_if_is_a_valid_active_storage_attribute'
+require 'matchers/shared_examples/has_valid_rspec_message_methods'
 require 'matchers/shared_examples/works_with_allow_blank'
 require 'matchers/shared_examples/works_with_both_instance_and_class'
 require 'matchers/shared_examples/works_with_context'
@@ -10,6 +11,7 @@
 describe ActiveStorageValidations::Matchers::AspectRatioValidatorMatcher do
   include MatcherHelpers
 
+  include HasValidRspecMessageMethods
   include ChecksIfIsAValidActiveStorageAttribute
   include WorksWithBothInstanceAndClass
 
diff --git a/test/matchers/attached_validator_matcher_test.rb b/test/matchers/attached_validator_matcher_test.rb
index d5c29494..39e1b718 100644
--- a/test/matchers/attached_validator_matcher_test.rb
+++ b/test/matchers/attached_validator_matcher_test.rb
@@ -2,6 +2,7 @@
 
 require 'test_helper'
 require 'matchers/shared_examples/checks_if_is_a_valid_active_storage_attribute'
+require 'matchers/shared_examples/has_valid_rspec_message_methods'
 require 'matchers/shared_examples/works_with_both_instance_and_class'
 require 'matchers/shared_examples/works_with_context'
 require 'matchers/shared_examples/works_with_custom_message'
@@ -9,6 +10,7 @@
 describe ActiveStorageValidations::Matchers::AttachedValidatorMatcher do
   include MatcherHelpers
 
+  include HasValidRspecMessageMethods
   include ChecksIfIsAValidActiveStorageAttribute
   include WorksWithBothInstanceAndClass
 
diff --git a/test/matchers/content_type_validator_matcher_test.rb b/test/matchers/content_type_validator_matcher_test.rb
index 19c90793..1c4e8445 100644
--- a/test/matchers/content_type_validator_matcher_test.rb
+++ b/test/matchers/content_type_validator_matcher_test.rb
@@ -2,6 +2,7 @@
 
 require 'test_helper'
 require 'matchers/shared_examples/checks_if_is_a_valid_active_storage_attribute'
+require 'matchers/shared_examples/has_valid_rspec_message_methods'
 require 'matchers/shared_examples/works_with_allow_blank'
 require 'matchers/shared_examples/works_with_both_instance_and_class'
 require 'matchers/shared_examples/works_with_context'
@@ -10,6 +11,7 @@
 describe ActiveStorageValidations::Matchers::ContentTypeValidatorMatcher do
   include MatcherHelpers
 
+  include HasValidRspecMessageMethods
   include ChecksIfIsAValidActiveStorageAttribute
   include WorksWithBothInstanceAndClass
 
diff --git a/test/matchers/dimension_validator_matcher_test.rb b/test/matchers/dimension_validator_matcher_test.rb
index 1c8ebf36..f2d28e57 100644
--- a/test/matchers/dimension_validator_matcher_test.rb
+++ b/test/matchers/dimension_validator_matcher_test.rb
@@ -2,6 +2,7 @@
 
 require 'test_helper'
 require 'matchers/shared_examples/checks_if_is_a_valid_active_storage_attribute'
+require 'matchers/shared_examples/has_valid_rspec_message_methods'
 require 'matchers/shared_examples/works_with_allow_blank'
 require 'matchers/shared_examples/works_with_both_instance_and_class'
 require 'matchers/shared_examples/works_with_context'
@@ -140,6 +141,7 @@ module OnlyMatchWhenExactValues
 describe ActiveStorageValidations::Matchers::DimensionValidatorMatcher do
   include MatcherHelpers
 
+  include HasValidRspecMessageMethods
   include ChecksIfIsAValidActiveStorageAttribute
   include WorksWithBothInstanceAndClass
 
diff --git a/test/matchers/shared_examples/has_valid_rspec_message_methods.rb b/test/matchers/shared_examples/has_valid_rspec_message_methods.rb
new file mode 100644
index 00000000..f6dfb9b1
--- /dev/null
+++ b/test/matchers/shared_examples/has_valid_rspec_message_methods.rb
@@ -0,0 +1,118 @@
+module HasValidRspecMessageMethods
+  extend ActiveSupport::Concern
+
+  included do
+    describe 'when the matcher returns a failure message to the dev' do
+      before do
+        case validator_sym
+        when :aspect_ratio then matcher.rejecting(:square)
+        when :attached then matcher
+        when :content_type then matcher.rejecting('image/png')
+        when :dimension then matcher.width(75).height(75)
+        when :size then matcher.less_than_or_equal_to(7.megabytes)
+        end
+      end
+
+      subject { matcher }
+
+      let(:model_attribute) { :failure_message }
+      let(:expected_failure_message) do
+        case validator_sym
+        when :aspect_ratio
+          <<~FAILURE_MESSAGE
+            is expected to validate aspect ratio of :#{model_attribute}
+          FAILURE_MESSAGE
+        when :attached
+          <<~FAILURE_MESSAGE
+            is expected to validate attachment of :#{model_attribute}
+          FAILURE_MESSAGE
+        when :content_type
+          <<~FAILURE_MESSAGE
+            is expected to validate the content types of :#{model_attribute}
+              the following content type should be rejected: :image/png
+              but :image/png was accepted
+          FAILURE_MESSAGE
+        when :dimension
+          <<~FAILURE_MESSAGE
+            is expected to validate dimensions of :#{model_attribute}
+              but there seem to have issues with the matcher methods you used, since:
+              validation failed when provided with a 74x75px test image
+              validation failed when provided with a 76x75px test image
+              validation failed when provided with a 75x75px test image
+              whereas it should have passed
+          FAILURE_MESSAGE
+        when :size
+          <<~FAILURE_MESSAGE
+            is expected to validate file size of :#{model_attribute}
+              but there seem to have issues with the matcher methods you used, since:
+              validation failed when provided with a 7340031 bytes test file
+              whereas it should have passed
+          FAILURE_MESSAGE
+        end[0..-2] # to remove last \n generated by the <<~ format
+      end
+
+      it { is_expected_to_have_failure_message(expected_failure_message) }
+    end
+
+    describe 'when the matcher returns a negated failure message to the dev' do
+      before do
+        case validator_sym
+        when :aspect_ratio then matcher.allowing(:square)
+        when :attached then matcher
+        when :content_type then matcher.allowing('image/png')
+        when :dimension then matcher.width(150).height(150)
+        when :size then matcher.less_than_or_equal_to(5.megabytes)
+        end
+      end
+
+      subject { matcher }
+
+      let(:model_attribute) { :failure_message_when_negated }
+      let(:expected_failure_message) do
+        case validator_sym
+        when :aspect_ratio
+          <<~FAILURE_MESSAGE
+            is expected not to validate aspect ratio of :#{model_attribute}
+          FAILURE_MESSAGE
+        when :attached
+          <<~FAILURE_MESSAGE
+            is expected not to validate attachment of :#{model_attribute}
+          FAILURE_MESSAGE
+        when :content_type
+          <<~FAILURE_MESSAGE
+            is expected not to validate the content types of :#{model_attribute}
+          FAILURE_MESSAGE
+        when :dimension
+          <<~MESSAGE
+            is expected not to validate dimensions of :#{model_attribute}
+              but there seem to have issues with the matcher methods you used, since:
+              validation failed when provided with a 149x150px test image
+              validation failed when provided with a 151x150px test image
+              validation failed when provided with a 150x149px test image
+              validation failed when provided with a 150x151px test image
+              whereas it should have passed
+          MESSAGE
+        when :size
+          <<~FAILURE_MESSAGE
+            is expected not to validate file size of :#{model_attribute}
+              but there seem to have issues with the matcher methods you used, since:
+              validation failed when provided with a 5242881 bytes test file
+              whereas it should have passed
+          FAILURE_MESSAGE
+        end[0..-2] # to remove last \n generated by the <<~ format
+      end
+
+      it { is_expected_to_have_failure_message_when_negated(expected_failure_message) }
+    end
+
+    describe 'when the dev asks for a description of the matcher' do
+      subject { matcher.description }
+
+      let(:model_attribute) { :failure_message_when_negated }
+
+      it "returns a string containing the attribute name" do
+        assert(subject.match(/#{model_attribute}/))
+      end
+    end
+  end
+end
diff --git a/test/matchers/size_validator_matcher_test.rb b/test/matchers/size_validator_matcher_test.rb
index fe85aad7..8d694d90 100644
--- a/test/matchers/size_validator_matcher_test.rb
+++ b/test/matchers/size_validator_matcher_test.rb
@@ -2,6 +2,7 @@
 
 require 'test_helper'
 require 'matchers/shared_examples/checks_if_is_a_valid_active_storage_attribute'
+require 'matchers/shared_examples/has_valid_rspec_message_methods'
 require 'matchers/shared_examples/works_with_allow_blank'
 require 'matchers/shared_examples/works_with_both_instance_and_class'
 require 'matchers/shared_examples/works_with_context'
@@ -60,6 +61,7 @@ module OnlyMatchWhenExactValue
 describe ActiveStorageValidations::Matchers::SizeValidatorMatcher do
   include MatcherHelpers
 
+  include HasValidRspecMessageMethods
   include ChecksIfIsAValidActiveStorageAttribute
   include WorksWithBothInstanceAndClass
 
diff --git a/test/matchers/support/matcher_helpers.rb b/test/matchers/support/matcher_helpers.rb
index dff6d578..c476484a 100644
--- a/test/matchers/support/matcher_helpers.rb
+++ b/test/matchers/support/matcher_helpers.rb
@@ -17,6 +17,16 @@ def is_expected_to_raise_error(error_class, message)
     end
   end
 
+  def is_expected_to_have_failure_message(expected_failure_message)
+    subject.matches?(klass)
+    assert_equal(subject.failure_message, expected_failure_message)
+  end
+
+  def is_expected_to_have_failure_message_when_negated(expected_failure_message)
+    subject.matches?(klass)
+    assert_equal(subject.failure_message_when_negated, expected_failure_message)
+  end
+
   def validator_class
     subject.class.name.sub(/::Matchers/, '').sub(/Matcher/, '').constantize
   end