1 files changed, 33 insertions, 0 deletions
diff --git a/spec/ruby/library/set/sortedset/subset_spec.rb b/spec/ruby/library/set/sortedset/subset_spec.rb
new file mode 100644
index 0000000000..7768692df6
--- /dev/null
+++ b/spec/ruby/library/set/sortedset/subset_spec.rb
@@ -0,0 +1,33 @@
+require_relative '../../../spec_helper'
+require 'set'
+
+describe "SortedSet#subset?" do
+  before :each do
+    @set = SortedSet[1, 2, 3, 4]
+  end
+
+  it "returns true if passed a SortedSet that is equal to self or self is a subset of" do
+    @set.subset?(@set).should be_true
+    SortedSet[].subset?(SortedSet[]).should be_true
+
+    SortedSet[].subset?(@set).should be_true
+    SortedSet[].subset?(SortedSet[1, 2, 3]).should be_true
+    SortedSet[].subset?(SortedSet["a", "b", "c"]).should be_true
+
+    SortedSet[1, 2, 3].subset?(@set).should be_true
+    SortedSet[1, 3].subset?(@set).should be_true
+    SortedSet[1, 2].subset?(@set).should be_true
+    SortedSet[1].subset?(@set).should be_true
+
+    SortedSet[5].subset?(@set).should be_false
+    SortedSet[1, 5].subset?(@set).should be_false
+    SortedSet["test"].subset?(@set).should be_false
+  end
+
+  it "raises an ArgumentError when passed a non-SortedSet" do
+    -> { SortedSet[].subset?([]) }.should raise_error(ArgumentError)
+    -> { SortedSet[].subset?(1) }.should raise_error(ArgumentError)
+    -> { SortedSet[].subset?("test") }.should raise_error(ArgumentError)
+    -> { SortedSet[].subset?(Object.new) }.should raise_error(ArgumentError)
+  end
+end