1 files changed, 91 insertions, 0 deletions
diff --git a/spec/ruby/core/hash/to_proc_spec.rb b/spec/ruby/core/hash/to_proc_spec.rb
new file mode 100644
index 0000000000..bc4756600d
--- /dev/null
+++ b/spec/ruby/core/hash/to_proc_spec.rb
@@ -0,0 +1,91 @@
+require_relative '../../spec_helper'
+require_relative 'fixtures/classes'
+
+describe "Hash#to_proc" do
+  before :each do
+    @key = Object.new
+    @value = Object.new
+    @hash = { @key => @value }
+    @default = Object.new
+    @unstored = Object.new
+  end
+
+  it "returns an instance of Proc" do
+    @hash.to_proc.should.instance_of? Proc
+  end
+
+  describe "the returned proc" do
+    before :each do
+      @proc = @hash.to_proc
+    end
+
+    it "is a lambda" do
+      @proc.should.lambda?
+    end
+
+    it "has an arity of 1" do
+      @proc.arity.should == 1
+    end
+
+    it "raises ArgumentError if not passed exactly one argument" do
+      -> {
+        @proc.call
+      }.should.raise(ArgumentError)
+
+      -> {
+        @proc.call 1, 2
+      }.should.raise(ArgumentError)
+    end
+
+    context "with a stored key" do
+      it "returns the paired value" do
+        @proc.call(@key).should.equal?(@value)
+      end
+    end
+
+    context "passed as a block" do
+      it "retrieves the hash's values" do
+        [@key].map(&@proc)[0].should.equal?(@value)
+      end
+
+      context "to instance_exec" do
+        it "always retrieves the original hash's values" do
+          hash = {foo: 1, bar: 2}
+          proc = hash.to_proc
+
+          hash.instance_exec(:foo, &proc).should == 1
+
+          hash2 = {quux: 1}
+          hash2.instance_exec(:foo, &proc).should == 1
+        end
+      end
+    end
+
+    context "with no stored key" do
+      it "returns nil" do
+        @proc.call(@unstored).should == nil
+      end
+
+      context "when the hash has a default value" do
+        before :each do
+          @hash.default = @default
+        end
+
+        it "returns the default value" do
+          @proc.call(@unstored).should.equal?(@default)
+        end
+      end
+
+      context "when the hash has a default proc" do
+        it "returns an evaluated value from the default proc" do
+          @hash.default_proc = -> hash, called_with { [hash.keys, called_with] }
+          @proc.call(@unstored).should == [[@key], @unstored]
+        end
+      end
+    end
+
+    it "raises an ArgumentError when calling #call on the Proc with no arguments" do
+      -> { @hash.to_proc.call }.should.raise(ArgumentError)
+    end
+  end
+end