Merge csv-3.2.6

Merged: https://github.com/ruby/ruby/pull/6890

test/csv/test_patterns.rb

@@ -0,0 +1,27 @@
+# frozen_string_literal: true
+
+require_relative "helper"
+
+class TestCSVPatternMatching < Test::Unit::TestCase
+
+  def test_hash
+    case CSV::Row.new(%i{A B C}, [1, 2, 3])
+    in B: b, C: c
+      assert_equal([2, 3], [b, c])
+    end
+  end
+
+  def test_hash_rest
+    case CSV::Row.new(%i{A B C}, [1, 2, 3])
+    in B: b, **rest
+      assert_equal([2, { A: 1, C: 3 }], [b, rest])
+    end
+  end
+
+  def test_array
+    case CSV::Row.new(%i{A B C}, [1, 2, 3])
+    in *, matched
+      assert_equal(3, matched)
+    end
+  end
+end