Removed one check from reduce_permits

Author: adamruzicka

lib/concurrent/atomic/semaphore.rb

@@ -109,6 +109,8 @@ def release(permits = 1)
     end
 
     # @!macro [attach] semaphore_method_reduce_permits
+    # 
+    #   @api private
     #
     #   Shrinks the number of available permits by the indicated reduction.
     #
@@ -123,10 +125,6 @@ def reduce_permits(reduction)
       unless reduction.is_a?(Fixnum) && reduction >= 0
         fail ArgumentError, 'reduction must be an non-negative integer'
       end
-      unless @free - reduction >= 0
-        fail(ArgumentError,
-             'cannot reduce number of available_permits below zero')
-      end
       @mutex.synchronize { @free -= reduction }
       nil 
     end
@@ -211,10 +209,6 @@ def reduce_permits(reduction)
         unless reduction.is_a?(Fixnum) && reduction >= 0
           fail ArgumentError, 'reduction must be an non-negative integer'
         end
-        unless @semaphore.availablePermits - reduction >= 0
-          fail(ArgumentError,
-               'cannot reduce number of available_permits below zero')
-        end
         @semaphore.reducePermits(reduction)
       end
     end

spec/concurrent/atomic/semaphore_spec.rb

@@ -86,10 +86,9 @@
       }.to raise_error(ArgumentError)
     end
 
-    it 'raises ArgumentError when reducing below zero' do
-      expect {
-        semaphore.reduce_permits 1000
-      }.to raise_error(ArgumentError)
+    it 'reduces permits below zero' do
+      semaphore.reduce_permits 1003
+      expect(semaphore.available_permits).to eq -1000
     end
 
     it 'reduces permits' do