1 files changed, 21 insertions, 0 deletions
diff --git a/spec/ruby/library/prime/instance_spec.rb b/spec/ruby/library/prime/instance_spec.rb
new file mode 100644
index 0000000000..680895eb64
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+++ b/spec/ruby/library/prime/instance_spec.rb
@@ -0,0 +1,21 @@
+require_relative '../../spec_helper'
+require 'prime'
+
+describe "Prime.instance" do
+  it "returns a object representing the set of prime numbers" do
+    Prime.instance.should.is_a?(Prime)
+  end
+
+  it "returns a object with no obsolete features" do
+    Prime.instance.should_not.respond_to?(:succ)
+    Prime.instance.should_not.respond_to?(:next)
+  end
+
+  it "does not complain anything" do
+    -> { Prime.instance }.should_not complain
+  end
+
+  it "raises a ArgumentError when is called with some arguments" do
+    -> { Prime.instance(1) }.should.raise(ArgumentError)
+  end
+end