1 files changed, 49 insertions, 0 deletions
diff --git a/spec/ruby/core/fiber/yield_spec.rb b/spec/ruby/core/fiber/yield_spec.rb
new file mode 100644
index 0000000000..12ec6ebcef
--- /dev/null
+++ b/spec/ruby/core/fiber/yield_spec.rb
@@ -0,0 +1,49 @@
+require_relative '../../spec_helper'
+
+describe "Fiber.yield" do
+  it "passes control to the Fiber's caller" do
+    step = 0
+    fiber = Fiber.new { step = 1; Fiber.yield; step = 2; Fiber.yield; step = 3 }
+    fiber.resume
+    step.should == 1
+    fiber.resume
+    step.should == 2
+  end
+
+  it "returns its arguments to the caller" do
+    fiber = Fiber.new { true; Fiber.yield :glark; true }
+    fiber.resume.should == :glark
+    fiber.resume
+  end
+
+  it "returns nil to the caller if given no arguments" do
+    fiber = Fiber.new { true; Fiber.yield; true }
+    fiber.resume.should == nil
+    fiber.resume
+  end
+
+  it "returns to the Fiber the value of the #resume call that invoked it" do
+    fiber = Fiber.new { Fiber.yield.should == :caller }
+    fiber.resume
+    fiber.resume :caller
+  end
+
+  it "does not propagate or reraise a rescued exception" do
+    fiber = Fiber.new do
+      begin
+        raise "an error in a Fiber"
+      rescue
+        Fiber.yield :first
+      end
+
+      :second
+    end
+
+    fiber.resume.should == :first
+    fiber.resume.should == :second
+  end
+
+  it "raises a FiberError if called from the root Fiber" do
+    ->{ Fiber.yield }.should.raise(FiberError)
+  end
+end