Revert "SortedSet was removed at a3db08d7b6ff119223f77e3df00b4f6deac971e2"

* This reverts commit b06ffce4aef002dc47c3c5968181230e7ab8d7cc.
* Do not revert specs, wrap them with `ruby_version_is` (tool for that in next commit).

1 files changed, 44 insertions, 0 deletions

diff --git a/spec/ruby/library/set/sortedset/flatten_spec.rb b/spec/ruby/library/set/sortedset/flatten_spec.rb
new file mode 100644
index 0000000000..ca4e4637e6
--- /dev/null
+++ b/spec/ruby/library/set/sortedset/flatten_spec.rb
@@ -0,0 +1,44 @@
+require_relative '../../../spec_helper'
+require 'set'
+
+# Note: Flatten make little sens on sorted sets, because SortedSets are not (by default)
+# comparable. For a SortedSet to be both valid and nested, we need to define a comparison operator:
+module SortedSet_FlattenSpecs
+  class ComparableSortedSet < SortedSet
+    def <=>(other)
+      return puts "#{other} vs #{self}" unless other.is_a?(ComparableSortedSet)
+      to_a <=> other.to_a
+    end
+  end
+end
+
+describe "SortedSet#flatten" do
+  it "returns a copy of self with each included SortedSet flattened" do
+    klass = SortedSet_FlattenSpecs::ComparableSortedSet
+    set = klass[klass[1,2], klass[3,4], klass[5,6,7], klass[8]]
+    flattened_set = set.flatten
+
+    flattened_set.should_not equal(set)
+    flattened_set.should == klass[1, 2, 3, 4, 5, 6, 7, 8]
+  end
+end
+
+describe "SortedSet#flatten!" do
+  it "flattens self" do
+    klass = SortedSet_FlattenSpecs::ComparableSortedSet
+    set = klass[klass[1,2], klass[3,4], klass[5,6,7], klass[8]]
+    set.flatten!
+    set.should == klass[1, 2, 3, 4, 5, 6, 7, 8]
+  end
+
+  it "returns self when self was modified" do
+    klass = SortedSet_FlattenSpecs::ComparableSortedSet
+    set = klass[klass[1,2], klass[3,4]]
+    set.flatten!.should equal(set)
+  end
+
+  it "returns nil when self was not modified" do
+    set = SortedSet[1, 2, 3, 4]
+    set.flatten!.should be_nil
+  end
+end