Added zipper

Wraps `Zip::OutputStream` to create an in memory zip file in order to answer a monad result for further processing.

Milestone: minor

app/aspects/zipper.rb

@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+
+require "dry/monads"
+require "initable"
+require "refinements/string"
+require "zip"
+
+module Terminus
+  module Aspects
+    # A monadic compressor of zip file content.
+    class Zipper
+      include Initable[io: Zip::OutputStream]
+      include Dry::Monads[:result]
+
+      using Refinements::String
+
+      def self.compress manifest, buffer
+        manifest.each do |name, content|
+          buffer.put_next_entry name
+          buffer.write content
+        end
+      end
+
+      def call manifest
+        io.write_buffer { self.class.compress manifest, it }
+          .tap(&:rewind)
+          .then { Success it }
+      rescue TypeError, Zip::Error => error
+        Failure error.message.up
+      end
+    end
+  end
+end

spec/app/aspects/zipper_spec.rb

@@ -0,0 +1,40 @@
+# frozen_string_literal: true
+
+require "hanami_helper"
+
+RSpec.describe Terminus::Aspects::Zipper do
+  subject(:zipper) { described_class.new }
+
+  describe "#call" do
+    let(:manifest) { {"one.txt" => "One", "two.txt" => "Two"} }
+
+    it "create zip file in memory" do
+      io = zipper.call(manifest).value!
+
+      content = Zip::File.open_buffer(io).each.with_object({}) do |entry, attributes|
+        attributes[entry.name] = entry.get_input_stream.read
+      end
+
+      expect(content).to eq(manifest)
+    end
+
+    it "answers StringIO instance" do
+      expect(zipper.call(manifest)).to match(Success(kind_of(StringIO)))
+    end
+
+    it "answers failure with invalid type" do
+      expect(zipper.call({bogus: Object.new})).to be_failure(
+        "No implicit conversion of Object into String"
+      )
+    end
+
+    it "answers failure with zip error" do
+      io = class_double Zip::OutputStream
+      zipper = described_class.new(io:)
+
+      allow(io).to receive(:write_buffer).and_raise(Zip::Error, "Danger!")
+
+      expect(zipper.call({test: "test"})).to be_failure("Danger!")
+    end
+  end
+end