Adds Module#synchronize for easier method-level synchronization.

1 files changed, 57 insertions, 0 deletions

diff --git a/activesupport/test/core_ext/module/synchronization_test.rb b/activesupport/test/core_ext/module/synchronization_test.rb
new file mode 100644
index 0000000000..78be6b725f
--- /dev/null
+++ b/activesupport/test/core_ext/module/synchronization_test.rb
@@ -0,0 +1,57 @@
+require 'abstract_unit'
+
+class SynchronizationTest < Test::Unit::TestCase
+  def setup
+    @target = Class.new
+    @target.cattr_accessor :mutex, :instance_writer => false
+    @target.mutex = Mutex.new
+    @instance = @target.new
+  end
+
+  def test_synchronize_aliases_method_chain_with_synchronize
+    @target.module_eval do
+      attr_accessor :value
+      synchronize :value, :with => :mutex
+    end
+    assert @instance.respond_to?(:value_with_synchronization)
+    assert @instance.respond_to?(:value_without_synchronization)
+  end
+
+  def test_synchronize_does_not_change_behavior
+    @target.module_eval do
+      attr_accessor :value
+      synchronize :value, :with => :mutex
+    end
+    expected = "some state"
+    @instance.value = expected
+    assert_equal expected, @instance.value
+  end
+
+  def test_synchronize_with_no_mutex_raises_an_argument_error
+    assert_raises(ArgumentError) do
+      @target.synchronize :to_s
+    end
+  end
+
+  def test_double_synchronize_raises_an_argument_error
+    @target.synchronize :to_s, :with => :mutex
+    assert_raises(ArgumentError) do
+      @target.synchronize :to_s, :with => :mutex
+    end
+  end
+
+  def test_mutex_is_entered_during_method_call
+    dummy = Object.new
+    def dummy.synchronize
+      @sync_count ||= 0
+      @sync_count += 1
+      yield
+    end
+    def dummy.sync_count; @sync_count; end
+    @target.mutex = dummy
+    @target.synchronize :to_s, :with => :mutex
+    @instance.to_s
+    @instance.to_s
+    assert_equal 2, dummy.sync_count
+  end
+end
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