Move class to lib, add sugar, add tests

config/initializers/xsd.rb

@@ -0,0 +1,2 @@
+require 'application_service'
+require 'xsd/util'

lib/application_service.rb

@@ -0,0 +1,5 @@
+class ApplicationService
+  def self.call(*args, &block)
+    new(*args, &block).call
+  end
+end

lib/xsd/util.rb

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+module Xsd
+  class Util < ApplicationService
+    SCHEMA_PATH = 'lib/schemas/'.freeze
+
+    attr_reader :xsd_schemas, :for_prefix
+
+    def initialize(params)
+      schema_path = params.fetch(:schema_path, SCHEMA_PATH)
+      @for_prefix = params.fetch(:for_prefix)
+      @xsd_schemas = Dir.entries(schema_path).select { |f| File.file? File.join(schema_path, f) }
+    end
+
+    def call
+      latest(for_prefix)
+    end
+
+    private
+
+    def latest(prefix)
+      schemas_by_name[prefix].last
+    end
+
+    def basename(filename)
+      File.basename(filename, '.xsd')
+    end
+
+    def prefix(filename)
+      regex = /([a-zA-Z]+-?[a-zA-Z]+)/
+
+      basename(filename).match(regex)[0]
+    end
+
+    def prefixes
+      xsd_schemas.map { |filename| prefix(filename) }.uniq
+    end
+
+    def schemas_by_name
+      prefixes.each_with_object({}) do |prefix, hash|
+        hash[prefix] = xsd_schemas.select { |filename| prefix_check(prefix, filename) }.uniq.sort
+      end
+    end
+
+    def prefix_check(prefix, filename)
+      version_regex = /\-\d+\S\d+/
+      (filename.include? prefix) && (filename.sub(prefix, '')[0, 4] =~ version_regex)
+    end
+  end
+end

test/lib/xsd_util/xsd_util_test.rb

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+require 'test_helper'
+require 'xsd/util'
+
+class XsdUtilTest < ActiveSupport::TestCase
+  def test_single_part_name
+    version = Xsd::Util.call(schema_path: 'test/fixtures/files/schemas', for_prefix: 'abcde')
+
+    assert_equal 'abcde-1.2.xsd', version
+  end
+
+  def test_double_part_name
+    version = Xsd::Util.call(schema_path: 'test/fixtures/files/schemas', for_prefix: 'abcde-fghij')
+
+    assert_equal 'abcde-fghij-1.3.xsd', version
+  end
+end