1 files changed, 68 insertions, 0 deletions
diff --git a/spec/ruby/core/hash/new_spec.rb b/spec/ruby/core/hash/new_spec.rb
new file mode 100644
index 0000000000..207fc2931f
--- /dev/null
+++ b/spec/ruby/core/hash/new_spec.rb
@@ -0,0 +1,68 @@
+require_relative '../../spec_helper'
+require_relative 'fixtures/classes'
+
+# Actually these are specs of Hash#initialize, there is no Hash.new it's just Class.new.
+describe "Hash.new" do
+  it "creates an empty Hash if passed no arguments" do
+    Hash.new.should == {}
+    Hash.new.size.should == 0
+  end
+
+  it "creates a new Hash with default object if passed a default argument" do
+    Hash.new(5).default.should == 5
+    Hash.new({}).default.should == {}
+  end
+
+  it "does not create a copy of the default argument" do
+    str = "foo"
+    Hash.new(str).default.should.equal?(str)
+  end
+
+  it "creates a Hash with a default_proc if passed a block" do
+    Hash.new.default_proc.should == nil
+
+    h = Hash.new { |x| "Answer to #{x}" }
+    h.default_proc.call(5).should == "Answer to 5"
+    h.default_proc.call("x").should == "Answer to x"
+  end
+
+  it "raises an ArgumentError if more than one argument is passed" do
+    -> { Hash.new(5,6) }.should.raise(ArgumentError)
+  end
+
+  it "raises an ArgumentError if passed both default argument and default block" do
+    -> { Hash.new(5) { 0 }   }.should.raise(ArgumentError)
+    -> { Hash.new(nil) { 0 } }.should.raise(ArgumentError)
+  end
+
+  ruby_version_is ""..."3.4" do
+    it "emits a deprecation warning if keyword arguments are passed" do
+      -> { Hash.new(unknown: true) }.should complain(
+        Regexp.new(Regexp.escape("Calling Hash.new with keyword arguments is deprecated and will be removed in Ruby 3.4; use Hash.new({ key: value }) instead"))
+      )
+
+      -> { Hash.new(1, unknown: true) }.should.raise(ArgumentError)
+      -> { Hash.new(unknown: true) { 0 } }.should.raise(ArgumentError)
+
+      Hash.new({ unknown: true }).default.should == { unknown: true }
+    end
+  end
+
+  ruby_version_is "3.4" do
+    it "accepts a capacity: argument" do
+      Hash.new(5, capacity: 42).default.should == 5
+      Hash.new(capacity: 42).default.should == nil
+      (Hash.new(capacity: 42) { 1 }).default_proc.should_not == nil
+    end
+
+    it "ignores negative capacity" do
+      -> { Hash.new(capacity: -42) }.should_not.raise
+    end
+
+    it "raises an error if unknown keyword arguments are passed" do
+      -> { Hash.new(unknown: true) }.should.raise(ArgumentError)
+      -> { Hash.new(1, unknown: true) }.should.raise(ArgumentError)
+      -> { Hash.new(unknown: true) { 0 } }.should.raise(ArgumentError)
+    end
+  end
+end