add a truncate method to the connection

it doesn't work on SQLite3 since it doesn't support truncate, but that's
OK.  If you call truncate on the connection, you're now bound to that
database (same as if you use hstore or any other db specific feature).

2 files changed, 23 insertions, 0 deletions

diff --git a/activerecord/test/cases/adapters/mysql2/connection_test.rb b/activerecord/test/cases/adapters/mysql2/connection_test.rb
index 0b2f59b0eb..62c5abbf41 100644
--- a/activerecord/test/cases/adapters/mysql2/connection_test.rb
+++ b/activerecord/test/cases/adapters/mysql2/connection_test.rb
@@ -4,6 +4,8 @@ require 'support/connection_helper'
 class MysqlConnectionTest < ActiveRecord::TestCase
   include ConnectionHelper
 
+  fixtures :comments
+
   def setup
     super
     @subscriber = SQLSubscriber.new
@@ -24,6 +26,17 @@ class MysqlConnectionTest < ActiveRecord::TestCase
     end
   end
 
+  def test_truncate
+    rows = ActiveRecord::Base.connection.exec_query("select count(*) from comments")
+    count = rows.first.values.first
+    assert_operator count, :>, 0
+
+    ActiveRecord::Base.connection.truncate("comments")
+    rows = ActiveRecord::Base.connection.exec_query("select count(*) from comments")
+    count = rows.first.values.first
+    assert_equal 0, count
+  end
+
   def test_no_automatic_reconnection_after_timeout
     assert @connection.active?
     @connection.update('set @@wait_timeout=1')
diff --git a/activerecord/test/cases/adapters/postgresql/connection_test.rb b/activerecord/test/cases/adapters/postgresql/connection_test.rb
index d26cda46fa..7d179944d4 100644
--- a/activerecord/test/cases/adapters/postgresql/connection_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/connection_test.rb
@@ -8,6 +8,8 @@ module ActiveRecord
     class NonExistentTable < ActiveRecord::Base
     end
 
+    fixtures :comments
+
     def setup
       super
       @subscriber = SQLSubscriber.new
@@ -20,6 +22,14 @@ module ActiveRecord
       super
     end
 
+    def test_truncate
+      count = ActiveRecord::Base.connection.execute("select count(*) from comments").first['count'].to_i
+      assert_operator count, :>, 0
+      ActiveRecord::Base.connection.truncate("comments")
+      count = ActiveRecord::Base.connection.execute("select count(*) from comments").first['count'].to_i
+      assert_equal 0, count
+    end
+
     def test_encoding
       assert_not_nil @connection.encoding
     end