Add option to specify CASCADE and RESTRICT for Truncation strategy

README.md

@@ -63,6 +63,8 @@ DatabaseCleaner[:active_record].strategy = DatabaseCleaner::ActiveRecord::Deleti
 
 * `:reset_ids` - Only valid for deletion strategy, when set to `true` resets ids to 1 after each table is cleaned.
 
+* `:truncate_option` - Only valid for PostgreSQL. Acceptable values are `:restrict` and `:cascade`. Default is `:restrict`
+
 ## Adapter configuration options
 
 `#db` defaults to the default ActiveRecord database, but can be specified manually in a few ways:

lib/database_cleaner/active_record/truncation.rb

@@ -5,7 +5,7 @@ module DatabaseCleaner
   module ActiveRecord
     class Truncation < Base
       def initialize(opts={})
-        if !opts.empty? && !(opts.keys - [:only, :except, :pre_count, :cache_tables, :reset_ids]).empty?
+        if !opts.empty? && !(opts.keys - [:only, :except, :pre_count, :cache_tables, :reset_ids, :truncate_option]).empty?
           raise ArgumentError, "The only valid options are :only, :except, :pre_count, :reset_ids, and :cache_tables. You specified #{opts.keys.join(',')}."
         end
 
@@ -14,6 +14,7 @@ def initialize(opts={})
 
         @reset_ids = opts[:reset_ids]
         @pre_count = opts[:pre_count]
+        @truncate_option = opts[:cascade] || :restrict
         @cache_tables = opts.has_key?(:cache_tables) ? !!opts[:cache_tables] : true
       end
 
@@ -22,7 +23,7 @@ def clean
           if pre_count? && connection.respond_to?(:pre_count_truncate_tables)
             connection.pre_count_truncate_tables(tables_to_truncate(connection))
           else
-            connection.truncate_tables(tables_to_truncate(connection))
+            connection.truncate_tables(tables_to_truncate(connection), { truncate_option: @cascade })
           end
         end
       end
@@ -96,7 +97,7 @@ def truncate_table(table_name)
           execute("DELETE FROM #{quote_table_name(table_name)}")
         end
 
-        def truncate_tables(tables)
+        def truncate_tables(tables, opts)
           tables.each { |t| truncate_table(t) }
         end
       end
@@ -146,7 +147,7 @@ def truncate_table(table_name)
           end
         end
 
-        def truncate_tables(tables)
+        def truncate_tables(tables, opts)
           tables.each { |t| truncate_table(t) }
         end
 
@@ -187,9 +188,10 @@ def database_tables
           tables_with_schema
         end
 
-        def truncate_tables(table_names)
+        def truncate_tables(table_names, opts)
           return if table_names.nil? || table_names.empty?
-          execute("TRUNCATE TABLE #{table_names.map{|name| quote_table_name(name)}.join(', ')} RESTART IDENTITY RESTRICT;")
+
+          execute("TRUNCATE TABLE #{table_names.map{|name| quote_table_name(name)}.join(', ')} RESTART IDENTITY #{opts[:truncate_option]};")
         end
 
         def pre_count_truncate_tables(tables)