Merge pull request #257 from sherbet/cleaning

DatabaseCleaner.cleaning

README.markdown

@@ -146,7 +146,7 @@ passed to [`keys`](http://redis.io/commands/keys)).
 
 (I should point out the truncation strategy will never truncate your schema_migrations table.)
 
-Some strategies require that you call `DatabaseCleaner.start` before calling `clean` (for example the `:transaction` one needs to know to open up a transaction). So you would have:
+Some strategies need to be started before tests are run (for example the `:transaction` strategy needs to know to open up a transaction). This can be accomplished by calling `DatabaseCleaner.start` at the beginning of the run, or by running the tests inside a block to `Database.cleaning`. So you would have:
 
 ```ruby
 require 'database_cleaner'
@@ -158,6 +158,12 @@ DatabaseCleaner.start # usually this is called in setup of a test
 dirty_the_db
 
 DatabaseCleaner.clean # cleanup of the test
+
+# OR
+
+DatabaseCleaner.cleaning do
+  dirty_the_db
+end
 ```
 
 At times you may want to do a single clean with one strategy.
@@ -196,12 +202,10 @@ RSpec.configure do |config|
     DatabaseCleaner.clean_with(:truncation)
   end
 
-  config.before(:each) do
-    DatabaseCleaner.start
+  config.around(:each) do |example|
+    DatabaseCleaner.cleaning do
+      example.run
     end
-
-  config.after(:each) do
-    DatabaseCleaner.clean
   end
 
 end
@@ -221,6 +225,13 @@ class MiniTest::Spec
     DatabaseCleaner.clean
   end
 end
+
+# with the minitest-around gem, this may be used instead:
+class Minitest::Spec
+  around do |tests|
+    DatabaseCleaner.cleaning(&tests)
+  end
+end
 ```
 
 ### Cucumber Example
@@ -239,12 +250,8 @@ rescue NameError
   raise "You need to add database_cleaner to your Gemfile (in the :test group) if you wish to use it."
 end
 
-Before do
-  DatabaseCleaner.start
-end
-
-After do |scenario|
-  DatabaseCleaner.clean
+Around do |scenario, block|
+  DatabaseCleaner.cleaning(&block)
 end
 ```
 
@@ -358,6 +365,9 @@ If you are using Postgres and have foreign key constraints, the truncation strat
 client_min_messages = warning
 ```
 
+### Nothing happens in JRuby with Sequel using transactions
+
+Due to an inconsistency in JRuby's implementation of Fibers, Sequel gives a different connection to `DatabaseCleaner.start` than is used for tests run between `.start` and `.clean`. This can be worked around by running your tests in a block like `DatabaseCleaner.cleaning { run_my_tests }` instead, which does not use Fibers. 
 
 ## Debugging
 

lib/database_cleaner/base.rb

@@ -88,6 +88,10 @@ module DatabaseCleaner
 
     alias clean! clean
 
+    def cleaning(&block)
+      strategy.cleaning(&block)
+    end
+
     def auto_detected?
       !!@autodetected
     end

lib/database_cleaner/configuration.rb

@@ -81,6 +81,12 @@ module DatabaseCleaner
 
     alias clean! clean
 
+    def cleaning(&inner_block)
+      connections.inject(inner_block) do |curr_block, connection|
+        proc { connection.cleaning(&curr_block) }
+      end.call
+    end
+
     def clean_with(*args)
       connections.each { |connection| connection.clean_with(*args) }
     end

lib/database_cleaner/cucumber.rb

@@ -1,11 +1,3 @@
-Before do
-  DatabaseCleaner.start
-end
-
-After do
-  begin
-    DatabaseCleaner.clean
-  rescue Exception =>  e
-    DatabaseCleaner.logger.error "Exception encountered by DatabaseCleaner in Cucumber After block: #{e}"
-  end
+Around do |scenario, block|
+  DatabaseCleaner.cleaning(&block)
 end

lib/database_cleaner/generic/base.rb

@@ -10,6 +10,12 @@ module ::DatabaseCleaner
          :default
        end
 
+       def cleaning(&block)
+         start
+         yield
+         clean
+       end
+
        module ClassMethods
          def available_strategies
            %W[]

lib/database_cleaner/sequel/transaction.rb

@@ -4,7 +4,18 @@ module DatabaseCleaner
     class Transaction
       include ::DatabaseCleaner::Sequel::Base
 
+      def self.check_fiber_brokenness
+        if !@checked_fiber_brokenness && Fiber.new { Thread.current }.resume != Thread.current
+          raise RuntimeError, "This ruby engine's Fibers are not compatible with Sequel's connection pool. " +
+            "To work around this, please use DatabaseCleaner.cleaning with a block instead of " +
+            "DatabaseCleaner.start and DatabaseCleaner.clean"
+        end
+        @checked_fiber_brokenness = true
+      end
+
       def start
+        self.class.check_fiber_brokenness
+
         @fibers||= []
         db= self.db
         f= Fiber.new do
@@ -20,6 +31,10 @@ module DatabaseCleaner
         f= @fibers.pop
         f.resume
       end
+
+      def cleaning
+        self.db.transaction(:rollback => :always, :savepoint => true) { yield }
+      end
     end
   end
 end

spec/database_cleaner/base_spec.rb

@@ -451,6 +451,13 @@ module DatabaseCleaner
           subject.clean!
         end
       end
+
+      describe "cleaning" do
+        it "should proxy cleaning to the strategy" do
+          strategy.should_receive(:cleaning)
+          subject.cleaning { }
+        end
+      end
     end
 
     describe "auto_detected?" do

spec/database_cleaner/configuration_spec.rb

@@ -163,6 +163,11 @@ describe ::DatabaseCleaner do
       ::DatabaseCleaner.clean
     end
 
+    it 'should proxy cleaning' do
+      connection.should_receive(:cleaning)
+      ::DatabaseCleaner.cleaning { }
+    end
+
     it "should proxy clean_with" do
       stratagem = double("stratgem")
       connection.should_receive(:clean_with).with(stratagem, {})
@@ -203,6 +208,28 @@ describe ::DatabaseCleaner do
         ::DatabaseCleaner.clean
       end
 
+      it "should initiate cleaning on each connection, yield, and finish cleaning each connection" do
+        [active_record, data_mapper].each do |connection|
+          mc = class << connection; self; end
+          mc.send(:attr_reader, :started, :cleaned)
+          mc.send(:define_method, 'cleaning') do |&block|
+            @started = true
+            block.call
+            @cleaned = true
+          end
+        end
+
+        ::DatabaseCleaner.cleaning do
+          active_record.started.should == true
+          data_mapper.started.should == true
+          active_record.cleaned.should == nil
+          data_mapper.cleaned.should == nil
+          @yielded = true
+        end
+        active_record.cleaned.should == true
+        data_mapper.cleaned.should == true
+      end
+
       it "should proxy clean_with to all connections" do
         stratagem = double("stratgem")
         active_record.should_receive(:clean_with).with(stratagem)

spec/database_cleaner/shared_strategy.rb

@@ -5,9 +5,11 @@ end
 shared_examples_for "a generic truncation strategy" do
   it { should respond_to(:start) }
   it { should respond_to(:clean) }
+  it { should respond_to(:cleaning) }
 end
 
 shared_examples_for "a generic transaction strategy" do
   it { should respond_to(:start) }
   it { should respond_to(:clean) }
+  it { should respond_to(:cleaning) }
 end