[Ruby 2.7] Add specs for pattern matching

core/array/deconstruct_spec.rb

@@ -0,0 +1,11 @@
+require_relative '../../spec_helper'
+
+ruby_version_is "2.7" do
+  describe "Array#deconstruct" do
+    it "returns self" do
+      array = [1]
+
+      array.deconstruct.should equal array
+    end
+  end
+end

core/hash/deconstruct_keys_spec.rb

@@ -0,0 +1,25 @@
+require_relative '../../spec_helper'
+
+ruby_version_is "2.7" do
+  describe "Hash#deconstruct_keys" do
+    it "returns self" do
+      hash = {a: 1, b: 2}
+
+      hash.deconstruct_keys([:a, :b]).should equal hash
+    end
+
+    it "requires one argument" do
+      -> {
+        {a: 1}.deconstruct_keys
+      }.should raise_error(ArgumentError, /wrong number of arguments \(given 0, expected 1\)/)
+    end
+
+    it "ignores argument" do
+      hash = {a: 1, b: 2}
+
+      hash.deconstruct_keys([:a]).should == {a: 1, b: 2}
+      hash.deconstruct_keys(0   ).should == {a: 1, b: 2}
+      hash.deconstruct_keys(''  ).should == {a: 1, b: 2}
+    end
+  end
+end

core/struct/deconstruct_keys_spec.rb

@@ -0,0 +1,50 @@
+require_relative '../../spec_helper'
+
+ruby_version_is "2.7" do
+  describe "Struct#deconstruct_keys" do
+    it "returns a hash of attributes" do
+      struct = Struct.new(:x, :y)
+      s = struct.new(1, 2)
+
+      s.deconstruct_keys([:x, :y]).should == {x: 1, y: 2}
+    end
+
+    it "requires one argument" do
+      -> {
+        Struct.new(:x).new(1).deconstruct_keys
+      }.should raise_error(ArgumentError, /wrong number of arguments \(given 0, expected 1\)/)
+    end
+
+    it "returns only specified keys" do
+      struct = Struct.new(:x, :y, :z)
+      s = struct.new(1, 2, 3)
+
+      s.deconstruct_keys([:x, :y]).should == {x: 1, y: 2}
+      s.deconstruct_keys([:x]    ).should == {x: 1}
+      s.deconstruct_keys([]      ).should == {}
+    end
+
+    it "accepts string attribute names" do
+      struct = Struct.new(:x, :y)
+      s = struct.new(1, 2)
+
+      s.deconstruct_keys(['x', 'y']).should == {'x' => 1, 'y' => 2}
+    end
+
+    it "accepts argument position number as well but returns them as keys" do
+      struct = Struct.new(:x, :y, :z)
+      s = struct.new(10, 20, 30)
+
+      s.deconstruct_keys([0, 1, 2]).should == {0 => 10, 1 => 20, 2 => 30}
+      s.deconstruct_keys([0, 1]   ).should == {0 => 10, 1 => 20}
+      s.deconstruct_keys([0]      ).should == {0 => 10}
+    end
+
+    it "ignores not existing attribute names" do
+      struct = Struct.new(:x, :y)
+      s = struct.new(1, 2)
+
+      s.deconstruct_keys([:a, :b, :c]).should == {}
+    end
+  end
+end

core/struct/deconstruct_spec.rb

@@ -0,0 +1,12 @@
+require_relative '../../spec_helper'
+
+ruby_version_is "2.7" do
+  describe "Struct#deconstruct" do
+    it "returns an array of attribute values" do
+      struct = Struct.new(:x, :y)
+      s = struct.new(1, 2)
+
+      s.deconstruct.should == [1, 2]
+    end
+  end
+end