Extend specs of Set#divide

library/set/divide_spec.rb

@@ -13,11 +13,11 @@
     ret.sort.should == ["five", "four", "one", "three", "two"]
   end
 
-  # BUG: Does not raise a LocalJumpError, but a NoMethodError
-  #
-  # it "raises a LocalJumpError when not passed a block" do
-  #   lambda { Set[1].divide }.should raise_error(LocalJumpError)
-  # end
+  it "returns an enumerator when not passed a block" do
+    ret = Set[1, 2, 3, 4].divide
+    ret.should be_kind_of(Enumerator)
+    ret.each(&:even?).should == Set[Set[1, 3], Set[2, 4]]
+  end
 end
 
 describe "Set#divide when passed a block with an arity of 2" do
@@ -31,4 +31,29 @@
     Set[1, 2].divide { |x, y| ret << [x, y] }
     ret.sort.should == [[1, 1], [1, 2], [2, 1], [2, 2]]
   end
+
+  it "returns an enumerator when not passed a block" do
+    ret = Set[1, 2, 3, 4].divide
+    ret.should be_kind_of(Enumerator)
+    ret.each { |a, b| (a + b).even? }.should == Set[Set[1, 3], Set[2, 4]]
+  end
+end
+
+describe "Set#divide when passed a block with an arity of > 2" do
+  it "only uses the first element if the arity > 2" do
+    set = Set["one", "two", "three", "four", "five"].divide do |x, y, z|
+      y.should be_nil
+      z.should be_nil
+      x.length
+    end
+    set.map { |x| x.to_a.sort }.sort.should == [["five", "four"], ["one", "two"], ["three"]]
+  end
+
+  it "only uses the first element if the arity = -1" do
+    set = Set["one", "two", "three", "four", "five"].divide do |*xs|
+      xs.size.should == 1
+      xs.first.length
+    end
+    set.map { |x| x.to_a.sort }.sort.should == [["five", "four"], ["one", "two"], ["three"]]
+  end
 end