Current progress

koans/about_blocks.rb

@@ -0,0 +1,96 @@
+require File.expand_path(File.dirname(__FILE__) + '/neo')
+
+class AboutBlocks < Neo::Koan
+  def method_with_block
+    result = yield
+    result
+  end
+
+  def test_methods_can_take_blocks
+    yielded_result = method_with_block { 1 + 2 }
+    assert_equal __, yielded_result
+  end
+
+  def test_blocks_can_be_defined_with_do_end_too
+    yielded_result = method_with_block do 1 + 2 end
+    assert_equal __, yielded_result
+  end
+
+  # ------------------------------------------------------------------
+
+  def method_with_block_arguments
+    yield("Jim")
+  end
+
+  def test_blocks_can_take_arguments
+    method_with_block_arguments do |argument|
+      assert_equal __, argument
+    end
+  end
+
+  # ------------------------------------------------------------------
+
+  def many_yields
+    yield(:peanut)
+    yield(:butter)
+    yield(:and)
+    yield(:jelly)
+  end
+
+  def test_methods_can_call_yield_many_times
+    result = []
+    many_yields { |item| result << item }
+    assert_equal __, result
+  end
+
+  # ------------------------------------------------------------------
+
+  def yield_tester
+    if block_given?
+      yield
+    else
+      :no_block
+    end
+  end
+
+  def test_methods_can_see_if_they_have_been_called_with_a_block
+    assert_equal __, yield_tester { :with_block }
+    assert_equal __, yield_tester
+  end
+
+  # ------------------------------------------------------------------
+
+  def test_block_can_affect_variables_in_the_code_where_they_are_created
+    value = :initial_value
+    method_with_block { value = :modified_in_a_block }
+    assert_equal __, value
+  end
+
+  def test_blocks_can_be_assigned_to_variables_and_called_explicitly
+    add_one = lambda { |n| n + 1 }
+    assert_equal __, add_one.call(10)
+
+    # Alternative calling syntax
+    assert_equal __, add_one[10]
+  end
+
+  def test_stand_alone_blocks_can_be_passed_to_methods_expecting_blocks
+    make_upper = lambda { |n| n.upcase }
+    result = method_with_block_arguments(&make_upper)
+    assert_equal __, result
+  end
+
+  # ------------------------------------------------------------------
+
+  def method_with_explicit_block(&block)
+    block.call(10)
+  end
+
+  def test_methods_can_take_an_explicit_block_argument
+    assert_equal __, method_with_explicit_block { |n| n * 2 }
+
+    add_one = lambda { |n| n + 1 }
+    assert_equal __, method_with_explicit_block(&add_one)
+  end
+
+end