[ruby/csv] Add `undef: :replace` for `CSV.open` (#129)

This PR adds `undef: :replace` option for `CSV.open`.

`File.open` has `undef: :replace` option, but `CSV.open` does not.
It would be convenient if `CSV.open` could have a shortcut by having
`undef: :replace` option.
https://github.com/ruby/csv/commit/cff8b18480

1 files changed, 22 insertions, 0 deletions

diff --git a/test/csv/interface/test_read.rb b/test/csv/interface/test_read.rb
index 58ec188f94..4b0f5e7e96 100644
--- a/test/csv/interface/test_read.rb
+++ b/test/csv/interface/test_read.rb
@@ -125,6 +125,28 @@ class TestCSVInterfaceRead < Test::Unit::TestCase
     end
   end
 
+  def test_open_with_undef_replace
+    # U+00B7 Middle Dot
+    CSV.open(@input.path, "w", encoding: Encoding::CP932, undef: :replace) do |rows|
+      rows << ["\u00B7"]
+    end
+    CSV.open(@input.path, encoding: Encoding::CP932) do |csv|
+      assert_equal([["?"]],
+                   csv.to_a)
+    end
+  end
+
+  def test_open_with_undef_replace_and_replace_string
+    # U+00B7 Middle Dot
+    CSV.open(@input.path, "w", encoding: Encoding::CP932, undef: :replace, replace: "X") do |rows|
+      rows << ["\u00B7"]
+    end
+    CSV.open(@input.path, encoding: Encoding::CP932) do |csv|
+      assert_equal([["X"]],
+                   csv.to_a)
+    end
+  end
+
   def test_parse
     assert_equal(@rows,
                  CSV.parse(@data, col_sep: "\t", row_sep: "\r\n"))