(PUP-11061) Override Sensitive equality/hash

Previously, instances of Sensitive with the same @value were not equal.
This patch overrides ==, eql? and hash to fix that.

  a = Puppet::Pops::Types::PSensitiveType::Sensitive.new('secret')
  b = Puppet::Pops::Types::PSensitiveType::Sensitive.new('secret')
  a == b
  # true
  h = { a => 1 }
  h[b] = 2
  h
  # {#<Sensitive [value redacted]>=>2}

Author: jpartlow

lib/puppet/pops/types/p_sensitive_type.rb

@@ -24,6 +24,16 @@ def to_s
     def inspect
       "#<#{self}>"
     end
+
+    def hash
+      @value.hash
+    end
+
+    def ==(other)
+      other.is_a?(Sensitive) &&
+        other.hash == hash
+    end
+    alias eql? ==
   end
 
   def self.register_ptype(loader, ir)

spec/unit/pops/types/p_sensitive_type_spec.rb

@@ -113,6 +113,24 @@ module Types
       expect(eval_and_collect_notices(code)).to eq(['Sensitive[Integer] != Sensitive[String]'])
     end
 
+    it 'equals another instance with the same value' do
+      code =<<-CODE
+        $i = Sensitive('secret')
+        $o = Sensitive('secret')
+        notice($i == $o)
+      CODE
+      expect(eval_and_collect_notices(code)).to eq(['true'])
+    end
+
+    it 'has equal hash keys for same values' do
+      code =<<-CODE
+        $i = Sensitive('secret')
+        $o = Sensitive('secret')
+        notice({$i => 1} == {$o => 1})
+      CODE
+      expect(eval_and_collect_notices(code)).to eq(['true'])
+    end
+
     it 'can be created from another sensitive instance ' do
       code =<<-CODE
         $o = Sensitive("hunter2")