[#224] Support custom data migration template

README.md

@@ -108,6 +108,7 @@ You can override this setting in `config/initializers/data_migrate.rb`
 ```ruby
 DataMigrate.configure do |config|
   config.data_migrations_path = 'db/awesomepath/'
+  config.data_template_path = Rails.root.join("lib", "awesomepath", "custom_data_migration.rb")
   config.db_configuration = {
     'host' => '127.0.0.1',
     'database' => 'awesome_database',

lib/data_migrate.rb

@@ -19,4 +19,7 @@
 end
 
 module DataMigrate
+  def self.root
+    File.dirname(__FILE__)
+  end
 end

lib/data_migrate/config.rb

@@ -12,12 +12,21 @@ def config
   end
 
   class Config
-    attr_accessor :data_migrations_path, :db_configuration, :spec_name
+    attr_accessor :data_migrations_path, :data_template_path, :db_configuration, :spec_name
+
+    DEFAULT_DATA_TEMPLATE_PATH = "data_migration.rb"
 
     def initialize
       @data_migrations_path = "db/data/"
+      @data_template_path = DEFAULT_DATA_TEMPLATE_PATH
       @db_configuration = nil
       @spec_name = nil
     end
+
+    def data_template_path=(value)
+      @data_template_path = value.tap do |path|
+        raise ArgumentError, "File not found: '#{path}'" unless path == DEFAULT_DATA_TEMPLATE_PATH || File.exists?(path)
+      end
+    end
   end
 end

lib/generators/data_migrate.rb

@@ -1,9 +1,22 @@
 require 'rails/generators/named_base'
+
 module DataMigrate
   module Generators
     class DataMigrationGenerator < Rails::Generators::NamedBase #:nodoc:
-      def self.source_root
-         @_data_migrate_source_root ||= File.expand_path(File.join(File.dirname(__FILE__), generator_name, 'templates'))
+      class << self
+        def source_root
+          build_data_migrate_source_root
+        end
+
+        private
+
+        def build_data_migrate_source_root
+          if DataMigrate.config.data_template_path == DataMigrate::Config::DEFAULT_DATA_TEMPLATE_PATH
+            File.expand_path(File.join(File.dirname(__FILE__), generator_name, 'templates'))
+          else
+            File.expand_path(File.dirname(DataMigrate.config.data_template_path))
+          end
+        end
       end
     end
   end

lib/generators/data_migration/data_migration_generator.rb

@@ -14,7 +14,7 @@ class DataMigrationGenerator < Rails::Generators::NamedBase
 
       def create_data_migration
         set_local_assigns!
-        migration_template "data_migration.rb", data_migrations_file_path
+        migration_template template_path, data_migrations_file_path
       end
 
       protected
@@ -26,6 +26,10 @@ def set_local_assigns!
         end
       end
 
+      def template_path
+        DataMigrate.config.data_template_path
+      end
+
       def migration_base_class_name
         "ActiveRecord::Migration[#{ActiveRecord::Migration.current_version}]"
       end

spec/data_migrate/config_spec.rb

@@ -1,12 +1,16 @@
 require "spec_helper"
 
 describe DataMigrate::Config do
-
   it "sets default data_migrations_path path", :no_override do
     expect(DataMigrate.config.data_migrations_path).to eq "db/data/"
   end
 
+  it "sets default data_template_path path", :no_override do
+    expect(DataMigrate.config.data_template_path).to eq DataMigrate::Config::DEFAULT_DATA_TEMPLATE_PATH
+  end
+
   describe "data migration path configured" do
+    subject { DataMigrate.config.data_migrations_path }
     before do
       @before = DataMigrate.config.data_migrations_path
       DataMigrate.configure do |config|
@@ -20,8 +24,43 @@
       end
     end
 
-    it do
-      expect(DataMigrate.config.data_migrations_path).to eq "db/awesome/"
+    it "equals the custom data migration path" do
+      is_expected.to eq "db/awesome/"
+    end
+  end
+
+  describe "data template path configured" do
+    subject { DataMigrate.config.data_template_path }
+
+    before do
+      @before = DataMigrate.config.data_template_path
+      DataMigrate.configure do |config|
+        config.data_template_path = data_template_path
+      end
+    end
+
+    let(:data_template_path) do
+      File.join(DataMigrate.root, "generators", "data_migration", "templates", "data_migration.rb")
+    end
+
+    after do
+      DataMigrate.configure do |config|
+        config.data_template_path = @before
+      end
+    end
+
+    it "equals the custom data template path" do
+      is_expected.to eq data_template_path
+    end
+
+    context "when path does not exist" do
+      subject { DataMigrate.config.data_template_path = invalid_path }
+
+      let(:invalid_path) { "lib/awesome/templates/data_migration.rb" }
+
+      it "checks that file exists on setting config var" do
+        expect { subject }.to raise_error { ArgumentError.new("File not found: '#{data_template_path}'") }
+      end
     end
   end
 end

spec/generators/data_migration/data_migration_generator_spec.rb

@@ -4,7 +4,8 @@
 require 'generators/data_migration/data_migration_generator'
 
 describe DataMigrate::Generators::DataMigrationGenerator do
-  let(:subject) { DataMigrate::Generators::DataMigrationGenerator }
+  subject { DataMigrate::Generators::DataMigrationGenerator }
+
   describe :next_migration_number do
     it "next migration" do
       Timecop.freeze("2016-12-03 22:15:26 -0800") do
@@ -19,14 +20,18 @@
   end
 
   describe :migration_base_class_name do
-    let(:subject) { DataMigrate::Generators::DataMigrationGenerator.new(['my_migration']) }
+    subject { generator.send(:migration_base_class_name) }
+
+    let(:generator) { DataMigrate::Generators::DataMigrationGenerator.new(['my_migration']) }
+
     it "returns the correct base class name" do
-      expect(subject.send(:migration_base_class_name)).to eq("ActiveRecord::Migration[#{ActiveRecord::Migration.current_version}]")
+      is_expected.to eq("ActiveRecord::Migration[#{ActiveRecord::Migration.current_version}]")
     end
   end
 
   describe :create_data_migration do
-    let(:subject) { DataMigrate::Generators::DataMigrationGenerator.new(['my_migration']) }
+    subject { DataMigrate::Generators::DataMigrationGenerator.new(['my_migration']) }
+
     let(:data_migrations_file_path) { 'abc/my_migration.rb' }
 
     context 'when custom data migrations path has a trailing slash' do
@@ -35,7 +40,7 @@
       end
 
       it 'returns correct file path' do
-        expect(subject).to receive(:migration_template).with(
+        is_expected.to receive(:migration_template).with(
           'data_migration.rb', data_migrations_file_path
         )
 
@@ -49,12 +54,48 @@
       end
 
       it 'returns correct file path' do
-        expect(subject).to receive(:migration_template).with(
+        is_expected.to receive(:migration_template).with(
           'data_migration.rb', data_migrations_file_path
         )
 
         subject.create_data_migration
       end
     end
   end
+
+  describe ".source_root" do
+    subject { described_class.source_root }
+
+    let(:default_source_root) do
+      File.expand_path(
+        File.dirname(File.join(DataMigrate.root, "generators", "data_migration", "templates", "data_migration.rb"))
+      )
+    end
+
+    it { is_expected.to eq default_source_root }
+
+    context "when DateMigrate.config.data_template_path is set" do
+      before do
+        @before = DataMigrate.config.data_template_path
+        DataMigrate.configure do |config|
+          config.data_template_path = data_template_path
+        end
+      end
+
+      let(:data_template_path) do
+        File.join(DataMigrate.root, "generators", "data_migration", "templates", "data_migration.rb")
+      end
+      let(:expected_source_root) { File.dirname(data_template_path) }
+
+      after do
+        DataMigrate.configure do |config|
+          config.data_template_path = @before
+        end
+      end
+
+      it "reads directory from config data template path" do
+        is_expected.to eq expected_source_root
+      end
+    end
+  end
 end