basic support for transaction/truncation with datamapper

examples/lib/datamapper.rb

@@ -0,0 +1,16 @@
+require "dm-core"
+
+# only to please activerecord API used in database_cleaner/examples/features/step_definitions
+# yes, i know that's lazy ...
+require "dm-validations"
+require "dm-aggregates"
+
+DataMapper.setup(:default, "sqlite3::memory:")
+
+class Widget
+  include DataMapper::Resource
+  property :id,   Serial
+  property :name, String
+end
+
+Widget.auto_migrate!

features/cleaning.feature

@@ -14,3 +14,5 @@ Feature: database cleaning
     | ORM          | Strategy      |
     | ActiveRecord | transaction   |
     | ActiveRecord | truncation    |
+    | DataMapper   | transaction   |
+    | DataMapper   | truncation    |

lib/database_cleaner/configuration.rb

@@ -12,7 +12,7 @@ module DatabaseCleaner
 
   module DataMapper
     def self.available_strategies
-      %w[]
+      %w[truncation transaction]
     end
   end
 
@@ -69,14 +69,14 @@ module DatabaseCleaner
 
     def orm
       @orm ||=begin
-                 if defined? ::ActiveRecord
-                  'active_record'
-                elsif defined? ::DataMapper
-                  'data_mapper'
-                else
-                  raise NoORMDetected, "No known ORM was detected!  Is ActiveRecord or DataMapper loaded?"
-                end
-              end
+        if defined? ::ActiveRecord
+          'active_record'
+        elsif defined? ::DataMapper
+          'data_mapper'
+        else
+          raise NoORMDetected, "No known ORM was detected!  Is ActiveRecord or DataMapper loaded?"
+        end
+      end
     end
 
 

lib/database_cleaner/data_mapper/transaction.rb

@@ -1,6 +1,23 @@
 module DatabaseCleaner::DataMapper
   class Transaction
 
-  end
+    def start(repo = :default)
+      repository(repo) do |r|
+        transaction = DataMapper::Transaction.new(r)
+        transaction.begin
+        r.adapter.push_transaction(transaction)
+      end
+    end
 
+    def clean(repo = :default)
+      repository(repo) do |r|
+        adapter = r.adapter
+        while adapter.current_transaction
+          adapter.current_transaction.rollback
+          adapter.pop_transaction
+        end
+      end
+    end
+
+  end
 end

lib/database_cleaner/data_mapper/truncation.rb

@@ -0,0 +1,131 @@
+module DataMapper
+  module Adapters
+    
+    class DataObjectsAdapter
+      
+      # make an equivalent to activerecord's Connection#tables method available
+      # dunno if there is a better/other way than this, or if this even works :)
+      def storage_names(repository = :default)
+        DataMapper::Resource.descendants.map { |model| model.storage_name(repository)}
+      end
+      
+    end
+    
+    class MysqlAdapter < DataObjectsAdapter
+      
+      def truncate_table(table_name)
+        execute("TRUNCATE TABLE #{quote_table_name(table_name)};")
+      end
+      
+      # copied from activerecord
+      def disable_referential_integrity
+        old = query("SELECT @@FOREIGN_KEY_CHECKS;")
+        begin
+          execute("SET FOREIGN_KEY_CHECKS = 0;")
+          yield
+        ensure
+          execute("SET FOREIGN_KEY_CHECKS = #{old};")
+        end
+      end
+    
+    end
+
+    class Sqlite3Adapter < DataObjectsAdapter
+      
+      def truncate_table(table_name)
+        execute("DELETE FROM #{quote_table_name(table_name)};")
+      end
+      
+      # this is a no-op copied from activerecord
+      # i didn't find out if/how this is possible
+      # activerecord also doesn't do more here
+      def disable_referential_integrity
+        yield
+      end
+      
+    end
+
+
+    # FIXME
+    # this definitely won't work!!!
+    # i basically just copied activerecord code to get a rough idea what they do
+    # anyways, i don't have postgres available, so i won't be the one to write this.
+    # maybe the stub codes below gets some postgres/datamapper user going, though.
+    class PostgresAdapter < DataObjectsAdapter
+      
+      def truncate_table(table_name)
+        execute("TRUNCATE TABLE #{quote_table_name(table_name)};")
+      end
+      
+      # FIXME
+      # copied from activerecord
+      def supports_disable_referential_integrity?
+        version = query("SHOW server_version")[0][0].split('.')
+        (version[0].to_i >= 8 && version[1].to_i >= 1) ? true : false
+      rescue
+        return false
+      end
+ 
+      # FIXME
+      # copied unchanged from activerecord
+      def disable_referential_integrity(repository = :default)
+        if supports_disable_referential_integrity? then
+          execute(storage_names(repository).collect do |name| 
+            "ALTER TABLE #{quote_table_name(name)} DISABLE TRIGGER ALL" 
+          end.join(";"))
+        end
+        yield
+      ensure
+        if supports_disable_referential_integrity? then
+          execute(storage_names(repository).collect do |name| 
+            "ALTER TABLE #{quote_table_name(name)} ENABLE TRIGGER ALL" 
+          end.join(";"))
+        end
+      end
+      
+    end
+
+  end
+  
+end
+
+
+module DatabaseCleaner::DataMapper
+  class Truncation
+
+    def initialize(options={})
+      if !options.empty? && !(options.keys - [:only, :except]).empty?
+        raise ArgumentError, "The only valid options are :only and :except. You specified #{options.keys.join(',')}."
+      end
+      if options.has_key?(:only) && options.has_key?(:except)
+        raise ArgumentError, "You may only specify either :only or :either.  Doing both doesn't really make sense does it?" 
+      end
+
+      @only = options[:only]
+      @tables_to_exclude = (options[:except] || []) << 'migration_info' # dm-migrations calls it like so
+    end
+    
+    
+    def start(repository = :default)
+      # no-op
+    end
+
+    def clean(repository = :default)
+      adapter = DataMapper.repository(repository).adapter
+      adapter.disable_referential_integrity do
+        tables_to_truncate.each do |table_name|
+          adapter.truncate_table table_name
+        end
+      end
+  end
+
+  private
+
+    # no idea if this works
+    def tables_to_truncate(repository = :default)
+      (@only || DataMapper.repository(repository).adapter.storage_names(repository)) - @tables_to_exclude
+    end
+
+  end
+
+end