Move Hash specs to rely less on shared examples

This is mostly a mechanical translation. A few things of interest:

Two shared specs weren't actually shared. `Hash#index` used to be an alias for `Hash#key` but was removed at some point. `Hash#values_at` had shared specs which never were actually shared.

Tests for `Hash#[]=` used `send`. I explicitly added back a test usign `send` to assert the return value.

I cleaned up requires, each test file can be run in isolation.

For `../mspec/bin/mspec core/hash`:

```
Before:
69 files, 633 examples, 1176 expectations, 0 failures, 0 errors, 0 tagged

After:
69 files, 558 examples, 1026 expectations, 0 failures, 0 errors, 0 tagged
```

So 75 fewer specs, 150 fewer assertions

Author: Earlopain

CONTRIBUTING.md

@@ -229,7 +229,7 @@ to avoid duplication of specs, we have shared specs that are re-used in other sp
 bit tricky however, so let's go over it.
 
 Commonly, if a shared spec is only reused within its own module, the shared spec will live within a
-shared directory inside that module's directory. For example, the `core/hash/shared/key.rb` spec is
+shared directory inside that module's directory. For example, the `core/hash/shared/iteration.rb` spec is
 only used by `Hash` specs, and so it lives inside `core/hash/shared/`.
 
 When a shared spec is used across multiple modules or classes, it lives within the `shared/` directory.
@@ -243,25 +243,25 @@ variables from the implementor spec: `@method` and `@object`, which the implemen
 Here's an example of a snippet of a shared spec and two specs which integrates it:
 
 ```ruby
-# core/hash/shared/key.rb
-describe :hash_key_p, shared: true do
-  it "returns true if the key's matching value was false" do
-    { xyz: false }.send(@method, :xyz).should == true
+# core/hash/shared/iteration.rb
+describe :hash_iteration_no_block, shared: true do
+  it "returns an Enumerator if called on a non-empty hash without a block" do
+    {}.send(@method).should.instance_of?(Enumerator)
   end
 end
 
-# core/hash/key_spec.rb
-describe "Hash#key?" do
-  it_behaves_like :hash_key_p, :key?
+# core/hash/select_spec.rb
+describe "Hash#select" do
+  it_behaves_like :hash_iteration_no_block, :select
 end
 
-# core/hash/include_spec.rb
-describe "Hash#include?" do
-  it_behaves_like :hash_key_p, :include?
+# core/hash/reject_spec.rb
+describe "Hash#reject?" do
+  it_behaves_like :hash_iteration_no_block, :reject
 end
 ```
 
-In the example, the first `describe` defines the shared spec `:hash_key_p`, which defines a spec that
+In the example, the first `describe` defines the shared spec `:hash_iteration_no_block`, which defines a spec that
 calls the `@method` method with an expectation. In the implementor spec, we use `it_behaves_like` to
 integrate the shared spec. `it_behaves_like` takes 3 parameters: the key of the shared spec, a method,
 and an object. These last two parameters are accessible via `@method` and `@object` in the shared spec.

core/hash/each_pair_spec.rb

@@ -1,11 +1,111 @@
 require_relative '../../spec_helper'
-require_relative 'fixtures/classes'
 require_relative 'shared/iteration'
-require_relative 'shared/each'
 require_relative '../enumerable/shared/enumeratorized'
 
 describe "Hash#each_pair" do
-  it_behaves_like :hash_each, :each_pair
   it_behaves_like :hash_iteration_no_block, :each_pair
   it_behaves_like :enumeratorized_with_origin_size, :each_pair, { 1 => 2, 3 => 4, 5 => 6 }
+
+  # This is inconsistent with below, MRI checks the block arity in rb_hash_each_pair()
+  it "yields a [[key, value]] Array for each pair to a block expecting |*args|" do
+    all_args = []
+    { 1 => 2, 3 => 4 }.each_pair { |*args| all_args << args }
+    all_args.sort.should == [[[1, 2]], [[3, 4]]]
+  end
+
+  it "yields the key and value of each pair to a block expecting |key, value|" do
+    r = {}
+    h = { a: 1, b: 2, c: 3, d: 5 }
+    h.each_pair { |k,v| r[k.to_s] = v.to_s }.should.equal?(h)
+    r.should == { "a" => "1", "b" => "2", "c" => "3", "d" => "5" }
+  end
+
+  it "yields the key only to a block expecting |key,|" do
+    ary = []
+    h = { "a" => 1, "b" => 2, "c" => 3 }
+    h.each_pair { |k,| ary << k }
+    ary.sort.should == ["a", "b", "c"]
+  end
+
+  it "always yields an Array of 2 elements, even when given a callable of arity 2" do
+    obj = Object.new
+    def obj.foo(key, value)
+    end
+
+    -> {
+      { "a" => 1 }.each_pair(&obj.method(:foo))
+    }.should.raise(ArgumentError)
+
+    -> {
+      { "a" => 1 }.each_pair(&-> key, value { })
+    }.should.raise(ArgumentError)
+  end
+
+  it "yields an Array of 2 elements when given a callable of arity 1" do
+    obj = Object.new
+    def obj.foo(key_value)
+      ScratchPad << key_value
+    end
+
+    ScratchPad.record([])
+    { "a" => 1 }.each_pair(&obj.method(:foo))
+    ScratchPad.recorded.should == [["a", 1]]
+  end
+
+  it "raises an error for a Hash when an arity enforcing callable of arity >2 is passed in" do
+    obj = Object.new
+    def obj.foo(key, value, extra)
+    end
+
+    -> {
+      { "a" => 1 }.each_pair(&obj.method(:foo))
+    }.should.raise(ArgumentError)
+  end
+
+  it "uses the same order as keys() and values()" do
+    h = { a: 1, b: 2, c: 3, d: 5 }
+    keys = []
+    values = []
+
+    h.each_pair do |k, v|
+      keys << k
+      values << v
+    end
+
+    keys.should == h.keys
+    values.should == h.values
+  end
+
+  # Confirming the argument-splatting works from child class for both k, v and [k, v]
+  it "properly expands (or not) child class's 'each'-yielded args" do
+    cls1 = Class.new(Hash) do
+      attr_accessor :k_v
+      def each
+        super do |k, v|
+          @k_v = [k, v]
+          yield k, v
+        end
+      end
+    end
+
+    cls2 = Class.new(Hash) do
+      attr_accessor :k_v
+      def each
+        super do |k, v|
+          @k_v = [k, v]
+          yield([k, v])
+        end
+      end
+    end
+
+    obj1 = cls1.new
+    obj1['a'] = 'b'
+    obj1.map {|k, v| [k, v]}.should == [['a', 'b']]
+    obj1.k_v.should == ['a', 'b']
+
+    obj2 = cls2.new
+    obj2['a'] = 'b'
+    obj2.map {|k, v| [k, v]}.should == [['a', 'b']]
+    obj2.k_v.should == ['a', 'b']
+  end
 end

core/hash/each_spec.rb

@@ -1,11 +1,7 @@
 require_relative '../../spec_helper'
-require_relative 'fixtures/classes'
-require_relative 'shared/iteration'
-require_relative 'shared/each'
-require_relative '../enumerable/shared/enumeratorized'
 
 describe "Hash#each" do
-  it_behaves_like :hash_each, :each
-  it_behaves_like :hash_iteration_no_block, :each
-  it_behaves_like :enumeratorized_with_origin_size, :each, { 1 => 2, 3 => 4, 5 => 6 }
+  it "is an alias of Hash#each_pair" do
+    Hash.instance_method(:each).should == Hash.instance_method(:each_pair)
+  end
 end

core/hash/element_set_spec.rb

@@ -1,7 +1,121 @@
 require_relative '../../spec_helper'
 require_relative 'fixtures/classes'
-require_relative 'shared/store'
 
 describe "Hash#[]=" do
-  it_behaves_like :hash_store, :[]=
+  it "associates the key with the value and return the value" do
+    h = { a: 1 }
+    h[:b] = 2
+    h.should == { b:2, a:1 }
+  end
+
+  it "returns the assigned value" do
+    h = {}
+    h.send(:[]=, 1, 2).should == 2
+  end
+
+  it "duplicates string keys using dup semantics" do
+    # dup doesn't copy singleton methods
+    key = +"foo"
+    def key.reverse() "bar" end
+    h = {}
+    h[key] = 0
+    h.keys[0].reverse.should == "oof"
+  end
+
+  it "stores unequal keys that hash to the same value" do
+    h = {}
+    k1 = ["x"]
+    k2 = ["y"]
+    # So they end up in the same bucket
+    k1.should_receive(:hash).and_return(0)
+    k2.should_receive(:hash).and_return(0)
+
+    h[k1] = 1
+    h[k2] = 2
+    h.size.should == 2
+  end
+
+  it "accepts keys with private #hash method" do
+    key = HashSpecs::KeyWithPrivateHash.new
+    h = {}
+    h[key] = "foo"
+    h[key].should == "foo"
+  end
+
+  it " accepts keys with an Integer hash" do
+    o = mock(hash: 1 << 100)
+    h = {}
+    h[o] = 1
+    h[o].should == 1
+  end
+
+  it "duplicates and freezes string keys" do
+    key = +"foo"
+    h = {}
+    h[key] = 0
+    key << "bar"
+
+    h.should == { "foo" => 0 }
+    h.keys[0].should.frozen?
+  end
+
+  it "doesn't duplicate and freeze already frozen string keys" do
+    key = "foo".freeze
+    h = {}
+    h[key] = 0
+    h.keys[0].should.equal?(key)
+  end
+
+  it "keeps the existing key in the hash if there is a matching one" do
+    h = { "a" => 1, "b" => 2, "c" => 3, "d" => 4 }
+    key1 = HashSpecs::ByValueKey.new(13)
+    key2 = HashSpecs::ByValueKey.new(13)
+    h[key1] = 41
+    key_in_hash = h.keys.last
+    key_in_hash.should.equal?(key1)
+    h[key2] = 42
+    last_key = h.keys.last
+    last_key.should.equal?(key_in_hash)
+    last_key.should_not.equal?(key2)
+  end
+
+  it "keeps the existing String key in the hash if there is a matching one" do
+    h = { "a" => 1, "b" => 2, "c" => 3, "d" => 4 }
+    key1 = "foo".dup
+    key2 = "foo".dup
+    key1.should_not.equal?(key2)
+    h[key1] = 41
+    frozen_key = h.keys.last
+    frozen_key.should_not.equal?(key1)
+    h[key2] = 42
+    h.keys.last.should.equal?(frozen_key)
+    h.keys.last.should_not.equal?(key2)
+  end
+
+  it "raises a FrozenError if called on a frozen instance" do
+    -> { HashSpecs.frozen_hash[1] = 2 }.should.raise(FrozenError)
+  end
+
+  it "does not raise an exception if changing the value of an existing key during iteration" do
+    hash = {1 => 2, 3 => 4, 5 => 6}
+    hash.each { hash[1] = :foo }
+    hash.should == {1 => :foo, 3 => 4, 5 => 6}
+  end
+
+  it "does not dispatch to hash for Boolean, Integer, Float, String, or Symbol" do
+    code = <<-EOC
+      load '#{fixture __FILE__, "name.rb"}'
+      hash = {}
+      [true, false, 1, 2.0, "hello", :ok].each do |value|
+        hash[value] = 42
+        raise "incorrect value" unless hash[value] == 42
+        hash[value] = 43
+        raise "incorrect value" unless hash[value] == 43
+      end
+      puts "OK"
+      puts hash.size
+    EOC
+    result = ruby_exe(code, args: "2>&1")
+    result.should == "OK\n6\n"
+  end
 end

core/hash/filter_spec.rb

@@ -1,10 +1,13 @@
 require_relative '../../spec_helper'
-require_relative 'shared/select'
 
 describe "Hash#filter" do
-  it_behaves_like :hash_select, :filter
+  it "is an alias of Hash#select" do
+    Hash.instance_method(:filter).should == Hash.instance_method(:select)
+  end
 end
 
 describe "Hash#filter!" do
-  it_behaves_like :hash_select!, :filter!
+  it "is an alias of Hash#select!" do
+    Hash.instance_method(:filter!).should == Hash.instance_method(:select!)
+  end
 end

core/hash/has_key_spec.rb

@@ -1,7 +1,7 @@
 require_relative '../../spec_helper'
-require_relative 'fixtures/classes'
-require_relative 'shared/key'
 
 describe "Hash#has_key?" do
-  it_behaves_like :hash_key_p, :has_key?
+  it "is an alias of Hash#include?" do
+    Hash.instance_method(:has_key?).should == Hash.instance_method(:include?)
+  end
 end

core/hash/has_value_spec.rb

@@ -1,7 +1,16 @@
 require_relative '../../spec_helper'
-require_relative 'fixtures/classes'
-require_relative 'shared/value'
 
 describe "Hash#has_value?" do
-  it_behaves_like :hash_value_p, :has_value?
+  it "returns true if the value exists in the hash" do
+    { a: :b }.has_value?(:a).should == false
+    { 1 => 2 }.has_value?(2).should == true
+    h = Hash.new(5)
+    h.has_value?(5).should == false
+    h = Hash.new { 5 }
+    h.has_value?(5).should == false
+  end
+
+  it "uses == semantics for comparing values" do
+    { 5 => 2.0 }.has_value?(2).should == true
+  end
 end

core/hash/include_spec.rb

@@ -1,7 +1,40 @@
 require_relative '../../spec_helper'
-require_relative 'fixtures/classes'
-require_relative 'shared/key'
 
 describe "Hash#include?" do
-  it_behaves_like :hash_key_p, :include?
+  it "returns true if argument is a key" do
+    h = { a: 1, b: 2, c: 3, 4 => 0 }
+    h.include?(:a).should == true
+    h.include?(:b).should == true
+    h.include?(2).should == false
+    h.include?(4).should == true
+
+    not_supported_on :opal do
+      h.include?('b').should == false
+      h.include?(4.0).should == false
+    end
+  end
+
+  it "returns true if the key's matching value was nil" do
+    { xyz: nil }.include?(:xyz).should == true
+  end
+
+  it "returns true if the key's matching value was false" do
+    { xyz: false }.include?(:xyz).should == true
+  end
+
+  it "returns true if the key is nil" do
+    { nil => 'b' }.include?(nil).should == true
+    { nil => nil }.include?(nil).should == true
+  end
+
+  it "compares keys with the same #hash value via #eql?" do
+    x = mock('x')
+    x.stub!(:hash).and_return(42)
+
+    y = mock('y')
+    y.stub!(:hash).and_return(42)
+    y.should_receive(:eql?).and_return(false)
+
+    { x => nil }.include?(y).should == false
+  end
 end