1 files changed, 38 insertions, 0 deletions
diff --git a/spec/ruby/core/thread/fetch_spec.rb b/spec/ruby/core/thread/fetch_spec.rb
new file mode 100644
index 0000000000..33ac3e0433
--- /dev/null
+++ b/spec/ruby/core/thread/fetch_spec.rb
@@ -0,0 +1,38 @@
+require File.expand_path('../../../spec_helper', __FILE__)
+
+ruby_version_is '2.5' do
+  describe 'Thread#fetch' do
+    describe 'with 2 arguments' do
+      it 'returns the value of the fiber-local variable if value has been assigned' do
+        th = Thread.new { Thread.current[:cat] = 'meow' }
+        th.join
+        th.fetch(:cat, true).should == 'meow'
+      end
+
+      it "returns the default value if fiber-local variable hasn't been assigned" do
+        th = Thread.new {}
+        th.join
+        th.fetch(:cat, true).should == true
+      end
+    end
+
+    describe 'with 1 argument' do
+      it 'raises a KeyError when the Thread does not have a fiber-local variable of the same name' do
+        th = Thread.new {}
+        th.join
+        -> { th.fetch(:cat) }.should raise_error(KeyError)
+      end
+
+      it 'returns the value of the fiber-local variable if value has been assigned' do
+        th = Thread.new { Thread.current[:cat] = 'meow' }
+        th.join
+        th.fetch(:cat).should == 'meow'
+      end
+    end
+
+    it 'raises an ArgumentError when not passed one or two arguments' do
+      -> { Thread.current.fetch() }.should raise_error(ArgumentError)
+      -> { Thread.current.fetch(1, 2, 3) }.should raise_error(ArgumentError)
+    end
+  end
+end