Move user version calculation to Repository

lib/pragma/migration/repository.rb

@@ -8,29 +8,58 @@ def sorted_versions
           versions.dup
         end
 
-        def migrations_since(user_version)
-          @versions.select { |version| version > user_version }.flat_map(&:migrations)
+        def user_version_proc
+          @user_version_proc ||= begin
+                                   lambda do |request|
+                                     request.get_header('X-Api-Version')
+                                   end
+                                 end
         end
 
-        def migration_active?(user_version, migration)
-          @versions.any? do |version|
-            version > user_version && version.migration?(migration)
+        def migrations_since(request_or_version)
+          user_version = if request_or_version.is_a?(Rack::Request)
+            user_version_from(request_or_version)
+          else
+            request_or_version
           end
+
+          @versions.select { |version| version > user_version }.flat_map(&:migrations)
         end
 
-        def migrations_applying_to(request, user_version:)
-          migrations_since(user_version).select do |migration|
+        def migrations_for(request)
+          migrations_since(request).select do |migration|
             migration.applies_to?(request)
           end
         end
 
+        def migration_active?(migration, request: nil, user_version: nil)
+          unless request || user_version
+            fail ArgumentError, 'You must pass one of :request or :user_version'
+          end
+
+          user_version ||= user_version_from(request)
+
+          @versions.any? do |version|
+            version > user_version && version.migration?(migration)
+          end
+        end
+
         protected
 
+        def user_version_from(request)
+          user_version = user_version_proc.call(request)
+          sorted_versions.include?(user_version) ? user_version : sorted_versions.last
+        end
+
         def version(number, migrations = [])
           versions << Version.new(number, migrations)
           sort_versions
         end
 
+        def user_version(&block)
+          @user_version_proc = block
+        end
+
         private
 
         def versions

lib/pragma/migration/runner.rb

@@ -3,34 +3,27 @@
 module Pragma
   module Migration
     class Runner
-      attr_reader :repository, :user_version
+      attr_reader :repository
 
-      def initialize(repository:, user_version:)
+      def initialize(repository)
         @repository = repository
-        @user_version = user_version
       end
 
       def run_upwards(request)
-        migrations_for(request).each do |migration|
+        repository.migrations_for(request).each do |migration|
           request = migration.new.up(request)
         end
 
         request
       end
 
       def run_downwards(request, response)
-        migrations_for(request).reverse.each do |migration|
+        repository.migrations_for(request).reverse.each do |migration|
           response = migration.new.down(response)
         end
 
         response
       end
-
-      private
-
-      def migrations_for(request)
-        repository.migrations_applying_to(request, user_version: user_version)
-      end
     end
   end
 end

spec/pragma/migration/repository_spec.rb

@@ -56,15 +56,15 @@
     end
 
     it 'returns false when the migration is not active' do
-      expect(repository.migration_active?('2017-12-25', migration1)).to eq(false)
+      expect(repository.migration_active?(migration1, user_version: '2017-12-25')).to eq(false)
     end
 
     it 'returns true when the migration is active' do
-      expect(repository.migration_active?('2017-12-25', migration2)).to eq(true)
+      expect(repository.migration_active?(migration2, user_version: '2017-12-25')).to eq(true)
     end
   end
 
-  describe '.migrations_applying_to' do
+  describe '.migrations_for' do
     let(:migration1) do
       Class.new(Pragma::Migration::Base) do
         apply_to '/api/v1/articles/*'
@@ -91,10 +91,10 @@
     end
 
     it 'returns the migrations applying to the current request' do
-      expect(repository.migrations_applying_to(
-        Rack::Request.new('PATH_INFO' => '/api/v1/articles/1'),
-        user_version: '2017-12-25'
-      )).to eq([migration2])
+      expect(repository.migrations_for(Rack::Request.new(
+        'PATH_INFO' => '/api/v1/articles/1',
+        'X-Api-Version' => '2017-12-25'
+      ))).to eq([migration2])
     end
   end
 end

spec/pragma/migration/runner_spec.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 RSpec.describe Pragma::Migration::Runner do
-  subject { described_class.new(repository: repository, user_version: user_version) }
+  subject { described_class.new(repository) }
 
   let(:repository) do
     Class.new(Pragma::Migration::Repository) do
@@ -90,7 +90,8 @@ def down(response)
     let(:request) do
       Rack::Request.new(
         'PATH_INFO' => '/api/v1/articles/1',
-        'rack.input' => ''
+        'rack.input' => '',
+        'X-Api-Version' => '2017-12-25'
       ).tap do |r|
         {
           'author_id' => 'test_id',
@@ -115,7 +116,8 @@ def down(response)
     let(:request) do
       Rack::Request.new(
         'PATH_INFO' => '/api/v1/articles/1',
-        'rack.input' => ''
+        'rack.input' => '',
+        'X-Api-Version' => '2017-12-25'
       ).tap do |r|
         {
           'author_id' => 'test_id',