1 files changed, 35 insertions, 11 deletions
diff --git a/spec/ruby/core/queue/initialize_spec.rb b/spec/ruby/core/queue/initialize_spec.rb
index 83c7e595fe..c6c1ae63c5 100644
--- a/spec/ruby/core/queue/initialize_spec.rb
+++ b/spec/ruby/core/queue/initialize_spec.rb
@@ -7,6 +7,10 @@ describe "Queue#initialize" do
     q.should.empty?
   end
 
+  it "is a private method" do
+    Queue.private_instance_methods.include?(:initialize).should == true
+  end
+
   ruby_version_is '3.1' do
     it "adds all elements of the passed Enumerable to self" do
       q = Queue.new([1, 2, 3])
@@ -18,21 +22,41 @@ describe "Queue#initialize" do
       q.should.empty?
     end
 
-    it "uses #to_a on the provided Enumerable" do
-      enumerable = MockObject.new('mock-enumerable')
-      enumerable.should_receive(:to_a).and_return([1, 2, 3])
-      q = Queue.new(enumerable)
-      q.size.should == 3
-      q.should_not.empty?
-      q.pop.should == 1
-      q.pop.should == 2
-      q.pop.should == 3
-      q.should.empty?
+    describe "converts the given argument to an Array using #to_a" do
+      it "uses #to_a on the provided Enumerable" do
+        enumerable = MockObject.new('mock-enumerable')
+        enumerable.should_receive(:to_a).and_return([1, 2, 3])
+        q = Queue.new(enumerable)
+        q.size.should == 3
+        q.should_not.empty?
+        q.pop.should == 1
+        q.pop.should == 2
+        q.pop.should == 3
+        q.should.empty?
+      end
+
+      it "raises a TypeError if the given argument can't be converted to an Array" do
+        -> { Queue.new(42) }.should raise_error(TypeError)
+        -> { Queue.new(:abc) }.should raise_error(TypeError)
+      end
+
+      it "raises a NoMethodError if the given argument raises a NoMethodError during type coercion to an Array" do
+        enumerable = MockObject.new('mock-enumerable')
+        enumerable.should_receive(:to_a).and_raise(NoMethodError)
+        -> { Queue.new(enumerable) }.should raise_error(NoMethodError)
+      end
     end
 
-    it "raises if the provided Enumerable does not respond to #to_a" do
+    it "raises TypeError if the provided Enumerable does not respond to #to_a" do
       enumerable = MockObject.new('mock-enumerable')
       -> { Queue.new(enumerable) }.should raise_error(TypeError, "can't convert MockObject into Array")
     end
+
+    it "raises TypeError if #to_a does not return Array" do
+      enumerable = MockObject.new('mock-enumerable')
+      enumerable.should_receive(:to_a).and_return("string")
+
+      -> { Queue.new(enumerable) }.should raise_error(TypeError, "can't convert MockObject to Array (MockObject#to_a gives String)")
+    end
   end
 end