Added preliminary interval skip list deletion examples

spec/runtime/interval_skip_list/delete_spec.rb

@@ -5,3 +5,79 @@ class IntervalSkipList
   public :insert_node, :delete_node, :head, :nodes
 end
 
+describe IntervalSkipList, " with nodes of height 1, 3, 1, 2, 3" do
+  attr_reader :list, :node
+  include IntervalSkipListSpecHelper
+
+  before do
+    @list = IntervalSkipList.new
+  end
+
+  it_should_behave_like "#next_node_height is deterministic"
+  def expected_node_heights
+    [1, 3, 1, 2, 3]
+  end
+
+  before do
+    list.insert(1..3, :b)
+    list.insert(1..5, :c)
+    list.insert(1..7, :d)
+    list.insert(1..9, :a)
+  end
+
+  describe " nodes[0]" do
+    before do
+      @node = list.nodes[0]
+    end
+
+    it "has a key of 1 and a height of 1" do
+      node.key.should == 1
+      node.height.should == 1
+    end
+  end
+
+  describe " nodes[1]" do
+    before do
+      @node = list.nodes[1]
+    end
+
+    it "has a key of 3 and a height of 3" do
+      node.key.should == 3
+      node.height.should == 3
+    end
+  end
+
+  describe " nodes[2]" do
+    before do
+      @node = list.nodes[2]
+    end
+
+    it "has a key of 5 and a height of 1" do
+      node.key.should == 5
+      node.height.should == 1
+    end
+  end
+
+  describe " nodes[3]" do
+    before do
+      @node = list.nodes[3]
+    end
+
+    it "has a key of 7 and a height of 2" do
+      node.key.should == 7
+      node.height.should == 2
+    end
+  end
+
+  describe " nodes[4]" do
+    before do
+      @node = list.nodes[4]
+    end
+
+    it "has a key of 9 and a height of 3" do
+      node.key.should == 9
+      node.height.should == 3
+    end
+  end
+
+end

spec/runtime/interval_skip_list/insert_spec.rb

@@ -15,12 +15,6 @@ def expected_node_heights
     [1, 3, 2, 3, 1]
   end
 
-  def confirm_containing_intervals(range, *markers)
-    (range.begin).upto(range.end) do |i|
-      list.containing(i).should have_markers(*markers)
-    end
-  end
-
   describe ", when :a is inserted on 1..7" do
     before do
       list.insert(1..7, :a)