add an_attachment_with_mime_type option to check mime_type of attachments (#1380)

* adding support for a mime_type attachment matcher

* add test for new mime_type attachment checker

* update README and CHANGELOG for an_attachment_with_mime_type

Author: tansaku

CHANGELOG.rdoc

@@ -16,5 +16,6 @@ Compatibility:
 
 Features:
 * Message#inspect_structure and PartsList#inspect_structure pretty-print the hierarchy of message parts. (TylerRick)
+* `an_attachment_with_mime_type` matcher added to match attachments by mime type
 
 Please check [2-7-stable](https://github.com/mikel/mail/blob/2-7-stable/CHANGELOG.rdoc) for previous changes.

README.md

@@ -645,6 +645,12 @@ describe "sending an email" do
   # ... or any attachment
   it { is_expected.to have_sent_email.with_attachments(any_attachment) }
 
+  # ... or attachment with filename
+  it { is_expected.to have_sent_email.with_attachments(an_attachment_with_filename('file.txt')) }
+
+  # ... or attachment with mime_type
+  it { is_expected.to have_sent_email.with_attachments(an_attachment_with_mime_type('application/pdf')) }
+
   # ... by array of attachments
   it { is_expected.to have_sent_email.with_attachments([my_attachment1, my_attachment2]) } #note that order is important
 

lib/mail/matchers/attachment_matchers.rb

@@ -9,6 +9,10 @@ def an_attachment_with_filename(filename)
       AttachmentFilenameMatcher.new(filename)
     end
 
+    def an_attachment_with_mime_type(filename)
+      AttachmentMimeTypeMatcher.new(filename)
+    end
+
     class AnyAttachmentMatcher
       def ===(other)
         other.attachment?
@@ -25,5 +29,16 @@ def ===(other)
         other.attachment? && other.filename == filename
       end
     end
+
+    class AttachmentMimeTypeMatcher
+      attr_reader :mime_type
+      def initialize(mime_type)
+        @mime_type = mime_type
+      end
+
+      def ===(other)
+        other.attachment? && other.mime_type == mime_type
+      end
+    end
   end
 end

spec/matchers_spec.rb

@@ -176,6 +176,10 @@
         it { is_expected.to have_sent_email.with_attachments(an_attachment_with_filename(first_attachment.filename)) }
       end
 
+      context 'matching by mimetype' do
+        it { is_expected.to have_sent_email.with_attachments(an_attachment_with_mime_type(first_attachment.mime_type)) }
+      end
+
       context 'single attachment passed' do
         it { is_expected.to have_sent_email.with_attachments(first_attachment) }
       end