assertions.rb: assert_throw

* lib/test/unit/assertions.rb (Test::Unit::Assertions#assert_throw):
  assertion for throw.  MiniTest::Assertions#assert_throws discards
  the cautht value.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42960 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,4 +1,8 @@
-Tue Sep 17 15:52:32 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+Tue Sep 17 15:53:20 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* lib/test/unit/assertions.rb (Test::Unit::Assertions#assert_throw):
+	  assertion for throw.  MiniTest::Assertions#assert_throws discards
+	  the cautht value.
 
 	* lib/test/unit/assertions.rb (Test::Unit::Assertions#assert_nothing_thrown):
 	  returns the result of the given block.

lib/test/unit/assertions.rb

@@ -169,6 +169,25 @@ module Test
         ret
       end
 
+      # :call-seq:
+      #   assert_throw( tag, failure_message = nil, &block )
+      #
+      #Fails unless the given block throws +tag+, returns the caught
+      #value otherwise.
+      #
+      #An optional failure message may be provided as the final argument.
+      #
+      #    tag = Object.new
+      #    assert_throw(tag, "#{tag} was not thrown!") do
+      #      throw tag
+      #    end
+      def assert_throw(tag, msg = nil)
+        catch(tag) do
+          yield(tag)
+          assert(false, message(msg) {"Expected #{mu_pp(tag)} to have been thrown"})
+        end
+      end
+
       # :call-seq:
       #   assert_equal( expected, actual, failure_message = nil )
       #