1 files changed, 59 insertions, 0 deletions
diff --git a/spec/ruby/core/kernel/to_enum_spec.rb b/spec/ruby/core/kernel/to_enum_spec.rb
new file mode 100644
index 0000000000..1cee26b694
--- /dev/null
+++ b/spec/ruby/core/kernel/to_enum_spec.rb
@@ -0,0 +1,59 @@
+require_relative '../../spec_helper'
+
+describe "Kernel#to_enum" do
+  it "is defined in Kernel" do
+    Kernel.method_defined?(:to_enum).should == true
+  end
+
+  it "returns a new enumerator" do
+    "abc".to_enum.should.instance_of?(Enumerator)
+  end
+
+  it "defaults the first argument to :each" do
+    enum = [1,2].to_enum
+    enum.map { |v| v }.should == [1,2].each { |v| v }
+  end
+
+  it "sets regexp matches in the caller" do
+    "wawa".to_enum(:scan, /./).map {|o| $& }.should == ["w", "a", "w", "a"]
+    a = []
+    "wawa".to_enum(:scan, /./).each {|o| a << $& }
+    a.should == ["w", "a", "w", "a"]
+  end
+
+  it "exposes multi-arg yields as an array" do
+    o = Object.new
+    def o.each
+      yield :a
+      yield :b1, :b2
+      yield [:c]
+      yield :d1, :d2
+      yield :e1, :e2, :e3
+    end
+
+    enum = o.to_enum
+    enum.next.should == :a
+    enum.next.should == [:b1, :b2]
+    enum.next.should == [:c]
+    enum.next.should == [:d1, :d2]
+    enum.next.should == [:e1, :e2, :e3]
+  end
+
+  it "uses the passed block's value to calculate the size of the enumerator" do
+    Object.new.to_enum { 100 }.size.should == 100
+  end
+
+  it "defers the evaluation of the passed block until #size is called" do
+    ScratchPad.record []
+
+    enum = Object.new.to_enum do
+      ScratchPad << :called
+      100
+    end
+
+    ScratchPad.recorded.should.empty?
+
+    enum.size
+    ScratchPad.recorded.should == [:called]
+  end
+end