optional/capi/string_spec.rb

# encoding: utf-8
require_relative 'spec_helper'
require_relative '../../shared/string/times'

load_extension('string')

describe :rb_str_new2, shared: true do
  it "returns a new string object calling strlen on the passed C string" do
    # Hardcoded to pass const char * = "hello\0invisible"
    @s.send(@method, "hello\0not used").should == "hello"
  end

  it "encodes the string with ASCII_8BIT" do
    @s.send(@method, "hello").encoding.should == Encoding::ASCII_8BIT
  end
end

describe "C-API String function" do
  before :each do
    @s = CApiStringSpecs.new
  end

  class ValidTostrTest
    def to_str
      "ruby"
    end
  end

  class InvalidTostrTest
    def to_str
      []
    end
  end

  describe "rb_str_set_len" do
    before :each do
      # Make a completely new copy of the string
      # for every example (#dup doesn't cut it).
      @str = "abcdefghij"[0..-1]
    end

    it "reduces the size of the string" do
      @s.rb_str_set_len(@str, 5).should == "abcde"
    end

    it "inserts a NULL byte at the length" do
      @s.rb_str_set_len(@str, 5).should == "abcde"
      @s.rb_str_set_len(@str, 8).should == "abcde\x00gh"
    end

    it "updates the byte size and character size" do
      @s.rb_str_set_len(@str, 4)
      @str.bytesize.should == 4
      @str.size.should == 4
      @str.should == "abcd"
    end

    it "updates the string's attributes visible in C code" do
      @s.rb_str_set_len_RSTRING_LEN(@str, 4).should == 4
    end

    it "can reveal characters written from C with RSTRING_PTR" do
      @s.rb_str_set_len(@str, 1)
      @str.should == "a"

      @str.force_encoding(Encoding::UTF_8)
      @s.RSTRING_PTR_set(@str, 1, 'B'.ord)
      @s.RSTRING_PTR_set(@str, 2, 'C'.ord)
      @s.rb_str_set_len(@str, 3)

      @str.bytesize.should == 3
      @str.should == "aBC"
    end
  end

  describe "rb_str_buf_new" do
    it "returns the equivalent of an empty string" do
      buf = @s.rb_str_buf_new(10, nil)
      buf.should == ""
      buf.bytesize.should == 0
      buf.size.should == 0
      @s.RSTRING_LEN(buf).should == 0
    end

    it "returns a string with the given capacity" do
      buf = @s.rb_str_buf_new(256, nil)
      @s.rb_str_capacity(buf).should == 256
    end

    it "returns a string that can be appended to" do
      str = @s.rb_str_buf_new(10, "defg")
      str << "abcde"
      str.should == "abcde"
    end

    it "returns a string that can be concatenated to another string" do
      str = @s.rb_str_buf_new(10, "defg")
      ("abcde" + str).should == "abcde"
    end

    it "returns a string whose bytes can be accessed by RSTRING_PTR" do
      str = @s.rb_str_buf_new(10, "abcdefghi")
      @s.rb_str_new(str, 10).should == "abcdefghi\x00"
    end

    it "returns a string that can be modified by rb_str_set_len" do
      str = @s.rb_str_buf_new(10, "abcdef")
      @s.rb_str_set_len(str, 4)
      str.should == "abcd"

      @s.rb_str_set_len(str, 8)
      str[0, 6].should == "abcd\x00f"
      @s.RSTRING_LEN(str).should == 8
    end

    it "can be used as a general buffer and reveal characters with rb_str_set_len" do
      str = @s.rb_str_buf_new(10, "abcdef")

      @s.RSTRING_PTR_set(str, 0, 195)
      @s.RSTRING_PTR_set(str, 1, 169)
      @s.rb_str_set_len(str, 2)

      str.force_encoding(Encoding::UTF_8)
      str.bytesize.should == 2
      str.size.should == 1
      str.should == "é"
    end
  end

  describe "rb_str_buf_new2" do
    it "returns a new string object calling strlen on the passed C string" do
      # Hardcoded to pass const char * = "hello\0invisible"
      @s.rb_str_buf_new2.should == "hello"
    end
  end

  describe "rb_str_new" do
    it "creates a new String with ASCII-8BIT Encoding" do
      @s.rb_str_new("", 0).encoding.should == Encoding::ASCII_8BIT
    end

    it "returns a new string object from a char buffer of len characters" do
      @s.rb_str_new("hello", 3).should == "hel"
    end

    it "returns an empty string if len is 0" do
      @s.rb_str_new("hello", 0).should == ""
    end

    it "copy length bytes and does not stop at the first \\0 byte" do
      @s.rb_str_new("he\x00llo", 6).should == "he\x00llo"
      @s.rb_str_new_native("he\x00llo", 6).should == "he\x00llo"
    end

    it "returns a string from an offset char buffer" do
      @s.rb_str_new_offset("hello", 1, 3).should == "ell"
    end
  end

  describe "rb_str_new2" do
    it_behaves_like :rb_str_new2, :rb_str_new2
  end

  describe "rb_str_new_cstr" do
    it_behaves_like :rb_str_new2, :rb_str_new_cstr
  end

  describe "rb_usascii_str_new" do
    it "creates a new String with US-ASCII Encoding from a char buffer of len characters" do
      str = "abc".force_encoding("us-ascii")
      result = @s.rb_usascii_str_new("abcdef", 3)
      result.should == str
      result.encoding.should == Encoding::US_ASCII
    end
  end

  describe "rb_usascii_str_new_cstr" do
    it "creates a new String with US-ASCII Encoding" do
      str = "abc".force_encoding("us-ascii")
      result = @s.rb_usascii_str_new_cstr("abc")
      result.should == str
      result.encoding.should == Encoding::US_ASCII
    end
  end

  describe "rb_str_encode" do
    it "returns a String in the destination encoding" do
      result = @s.rb_str_encode("abc", Encoding::ISO_8859_1, 0, nil)
      result.encoding.should == Encoding::ISO_8859_1
    end

    it "transcodes the String" do
      result = @s.rb_str_encode("ありがとう", "euc-jp", 0, nil)
      euc_jp = [0xa4, 0xa2, 0xa4, 0xea, 0xa4, 0xac, 0xa4, 0xc8, 0xa4, 0xa6].pack('C*').force_encoding("euc-jp")
      result.should == euc_jp
      result.encoding.should == Encoding::EUC_JP
    end

    it "returns a dup of the original String" do
      a = "abc"
      b = @s.rb_str_encode("abc", "us-ascii", 0, nil)
      a.should_not equal(b)
    end

    it "returns a duplicate of the original when the encoding doesn't change" do
      a = "abc"
      b = @s.rb_str_encode("abc", Encoding::UTF_8, 0, nil)
      a.should_not equal(b)
    end

    it "accepts encoding flags" do
      xFF = [0xFF].pack('C').force_encoding('utf-8')
      result = @s.rb_str_encode("a#{xFF}c", "us-ascii",
                                Encoding::Converter::INVALID_REPLACE, nil)
      result.should == "a?c"
      result.encoding.should == Encoding::US_ASCII
    end

    it "accepts an encoding options Hash specifying replacement String" do
      # Yeah, MRI aborts with rb_bug() if the options Hash is not frozen
      options = { replace: "b" }.freeze
      xFF = [0xFF].pack('C').force_encoding('utf-8')
      result = @s.rb_str_encode("a#{xFF}c", "us-ascii",
                                Encoding::Converter::INVALID_REPLACE,
                                options)
      result.should == "abc"
      result.encoding.should == Encoding::US_ASCII
    end
  end

  describe "rb_str_new3" do
    it "returns a copy of the string" do
      str1 = "hi"
      str2 = @s.rb_str_new3 str1
      str1.should == str2
      str1.should_not equal str2
    end
  end

  describe "rb_str_new4" do
    it "returns the original string if it is already frozen" do
      str1 = "hi"
      str1.freeze
      str2 = @s.rb_str_new4 str1
      str1.should == str2
      str1.should equal(str2)
      str1.frozen?.should == true
      str2.frozen?.should == true
    end

    it "returns a frozen copy of the string" do
      str1 = "hi"
      str2 = @s.rb_str_new4 str1
      str1.should == str2
      str1.should_not equal(str2)
      str2.frozen?.should == true
    end
  end

  describe "rb_str_dup" do
    it "returns a copy of the string" do
      str1 = "hi"
      str2 = @s.rb_str_dup str1
      str1.should == str2
      str1.should_not equal str2
    end
  end

  describe "rb_str_new5" do
    it "returns a new string with the same class as the passed string" do
      string_class = Class.new(String)
      template_string = string_class.new("hello world")
      new_string = @s.rb_str_new5(template_string, "hello world", 11)

      new_string.should == "hello world"
      new_string.class.should == string_class
    end
  end

  describe "rb_tainted_str_new" do
    it "creates a new tainted String" do
      newstring = @s.rb_tainted_str_new("test", 4)
      newstring.should == "test"
      newstring.tainted?.should be_true
    end
  end

  describe "rb_tainted_str_new2" do
    it "creates a new tainted String" do
      newstring = @s.rb_tainted_str_new2("test")
      newstring.should == "test"
      newstring.tainted?.should be_true
    end
  end

  describe "rb_str_append" do
    it "appends a string to another string" do
      @s.rb_str_append("Hello", " Goodbye").should == "Hello Goodbye"
    end

    it "raises a TypeError trying to append non-String-like object" do
      lambda { @s.rb_str_append("Hello", 32323)}.should raise_error(TypeError)
    end

    it "changes Encoding if a string is appended to an empty string" do
      string = "パスタ".encode(Encoding::ISO_2022_JP)
      @s.rb_str_append("", string).encoding.should == Encoding::ISO_2022_JP
    end
  end

  describe "rb_str_plus" do
    it "returns a new string from concatenating two other strings" do
      @s.rb_str_plus("Hello", " Goodbye").should == "Hello Goodbye"
    end
  end

  describe "rb_str_times" do
    it_behaves_like :string_times, :rb_str_times, ->(str, times) { @s.rb_str_times(str, times) }
  end

  describe "rb_str_buf_cat" do
    it "concatenates a C string to a ruby string" do
      @s.rb_str_buf_cat("Your house is on fire").should == "Your house is on fire?"
    end
  end

  describe "rb_str_cat" do
    it "concatenates a C string to ruby string" do
      @s.rb_str_cat("Your house is on fire").should == "Your house is on fire?"
    end
  end

  describe "rb_str_cat2" do
    it "concatenates a C string to a ruby string" do
      @s.rb_str_cat2("Your house is on fire").should == "Your house is on fire?"
    end
  end

  describe "rb_str_cmp" do
    it "returns 0 if two strings are identical" do
      @s.rb_str_cmp("ppp", "ppp").should == 0
    end

    it "returns -1 if the first string is shorter than the second" do
      @s.rb_str_cmp("xxx", "xxxx").should == -1
    end

    it "returns -1 if the first string is lexically less than the second" do
      @s.rb_str_cmp("xxx", "yyy").should == -1
    end

    it "returns 1 if the first string is longer than the second" do
      @s.rb_str_cmp("xxxx", "xxx").should == 1
    end

    it "returns 1 if the first string is lexically greater than the second" do
      @s.rb_str_cmp("yyy", "xxx").should == 1
    end
  end

  describe "rb_str_split" do
    it "splits strings over a splitter" do
      @s.rb_str_split("Hello,Goodbye").should == ["Hello", "Goodbye"]
    end
  end

  describe "rb_str2inum" do
    it "converts a string to a number given a base" do
      @s.rb_str2inum("10", 10).should == 10
      @s.rb_str2inum("A", 16).should == 10
    end
  end

  describe "rb_cstr2inum" do
    it "converts a C string to a Fixnum given a base" do
      @s.rb_cstr2inum("10", 10).should == 10
      @s.rb_cstr2inum("10", 16).should == 16
    end

    it "converts a C string to a Bignum given a base" do
      @s.rb_cstr2inum(bignum_value.to_s, 10).should == bignum_value
    end

    it "converts a C string to a Fixnum non-strictly if base is not 0" do
      @s.rb_cstr2inum("1234a", 10).should == 1234
    end

    it "converts a C string to a Fixnum strictly if base is 0" do
      lambda { @s.rb_cstr2inum("1234a", 0) }.should raise_error(ArgumentError)
    end
  end

  describe "rb_cstr_to_inum" do
    it "converts a C string to a Fixnum given a base" do
      @s.rb_cstr_to_inum("1234", 10, true).should == 1234
    end

    it "converts a C string to a Bignum given a base" do
      @s.rb_cstr_to_inum(bignum_value.to_s, 10, true).should == bignum_value
    end

    it "converts a C string to a Fixnum non-strictly" do
      @s.rb_cstr_to_inum("1234a", 10, false).should == 1234
    end

    it "converts a C string to a Fixnum strictly" do
      lambda { @s.rb_cstr_to_inum("1234a", 10, true) }.should raise_error(ArgumentError)
    end
  end

  describe "rb_str_subseq" do
    it "returns a byte-indexed substring" do
      str = "\x00\x01\x02\x03\x04".force_encoding("binary")
      @s.rb_str_subseq(str, 1, 2).should == "\x01\x02".force_encoding("binary")
    end
  end

  describe "rb_str_substr" do
    it "returns a substring" do
      "hello".length.times do |time|
        @s.rb_str_substr("hello", 0, time + 1).should == "hello"[0..time]
      end
    end
  end

  describe "rb_str_to_str" do
    it "calls #to_str to coerce the value to a String" do
      @s.rb_str_to_str("foo").should == "foo"
      @s.rb_str_to_str(ValidTostrTest.new).should == "ruby"
    end

    it "raises a TypeError if coercion fails" do
      lambda { @s.rb_str_to_str(0) }.should raise_error(TypeError)
      lambda { @s.rb_str_to_str(InvalidTostrTest.new) }.should raise_error(TypeError)
    end
  end

  describe "RSTRING_PTR" do
    it "returns a pointer to the string's contents" do
      str = "abc"
      chars = []
      @s.RSTRING_PTR_iterate(str) do |c|
        chars << c
      end
      chars.should == [97, 98, 99]
    end

    it "allows changing the characters in the string" do
      str = "abc"
      @s.RSTRING_PTR_assign(str, 'A'.ord)
      str.should == "AAA"
    end

    it "reflects changes after a rb_funcall" do
      lamb = proc { |s| s.replace "NEW CONTENT" }

      str = "beforebefore"

      ret = @s.RSTRING_PTR_after_funcall(str, lamb)

      str.should == "NEW CONTENT"
      ret.should == str
    end

    it "reflects changes from native memory and from String#setbyte in bounds" do
      str = "abc"
      from_rstring_ptr = @s.RSTRING_PTR_after_yield(str) { str.setbyte(1, 'B'.ord) }
      from_rstring_ptr.should == "1B2"
      str.should == "1B2"
    end

    it "returns a pointer to the contents of encoded pointer-sized string" do
      s = "70パク".
        encode(Encoding::UTF_16LE).
        force_encoding(Encoding::UTF_16LE).
        encode(Encoding::UTF_8)

      chars = []
      @s.RSTRING_PTR_iterate(s) do |c|
        chars << c
      end
      chars.should == [55, 48, 227, 131, 145, 227, 130, 175]
    end
  end

  describe "RSTRING_LEN" do
    it "returns the size of the string" do
      @s.RSTRING_LEN("gumdrops").should == 8
    end
  end

  describe "RSTRING_LENINT" do
    it "returns the size of a string" do
      @s.RSTRING_LENINT("silly").should == 5
    end
  end

  describe :string_value_macro, shared: true do
    before :each do
      @s = CApiStringSpecs.new
    end

    it "does not call #to_str on a String" do
      str = "genuine"
      str.should_not_receive(:to_str)
      @s.send(@method, str)
    end

    it "does not call #to_s on a String" do
      str = "genuine"
      str.should_not_receive(:to_str)
      @s.send(@method, str)
    end

    it "calls #to_str on non-String objects" do
      str = mock("fake")
      str.should_receive(:to_str).and_return("wannabe")
      @s.send(@method, str).should == "wannabe"
    end

    it "does not call #to_s on non-String objects" do
      str = mock("fake")
      str.should_not_receive(:to_s)
      lambda { @s.send(@method, str) }.should raise_error(TypeError)
    end
  end

  describe "StringValue" do
    it_behaves_like :string_value_macro, :StringValue
  end

  describe "SafeStringValue" do
    it "raises for tained string when $SAFE is 1" do
      begin
        Thread.new {
          $SAFE = 1
          lambda {
            @s.SafeStringValue("str".taint)
          }.should raise_error(SecurityError)
        }.join
      ensure
        $SAFE = 0
      end
    end

    it_behaves_like :string_value_macro, :SafeStringValue
  end

  describe "rb_str_resize" do
    it "reduces the size of the string" do
      str = @s.rb_str_resize("test", 2)
      str.size.should == 2
      @s.RSTRING_LEN(str).should == 2
      str.should == "te"
    end

    it "updates the string's attributes visible in C code" do
      @s.rb_str_resize_RSTRING_LEN("test", 2).should == 2
    end

    it "increases the size of the string" do
      expected = "test".force_encoding("US-ASCII")
      str = @s.rb_str_resize(expected.dup, 12)
      str.size.should == 12
      @s.RSTRING_LEN(str).should == 12
      str[0, 4].should == expected
    end
  end

  describe "rb_str_inspect" do
    it "returns the equivalent of calling #inspect on the String" do
      @s.rb_str_inspect("value").should == %["value"]
    end
  end

  describe "rb_str_intern" do
    it "returns a symbol created from the string" do
      @s.rb_str_intern("symbol").should == :symbol
    end

    it "returns a symbol even if passed an empty string" do
      @s.rb_str_intern("").should == "".to_sym
    end

    it "returns a symbol even if the passed string contains NULL characters" do
      @s.rb_str_intern("no\0no").should == "no\0no".to_sym
    end
  end

  describe "rb_str_freeze" do
    it "freezes the string" do
      s = ""
      @s.rb_str_freeze(s).should == s
      s.frozen?.should be_true
    end
  end

  describe "rb_str_hash" do
    it "hashes the string into a number" do
      s = "hello"
      @s.rb_str_hash(s).should be_kind_of(Integer)
    end
  end

  describe "rb_str_update" do
    it "splices the replacement string into the original at the given location" do
      @s.rb_str_update("hello", 2, 3, "wuh").should == "hewuh"
    end
  end
end

describe "rb_str_free" do
  # This spec only really exists to make sure the symbol
  # is available. There is no guarantee this even does
  # anything at all
  it "indicates data for a string might be freed" do
    @s.rb_str_free("xyz").should be_nil
  end
end

describe :rb_external_str_new, shared: true do
  it "returns a String in the default external encoding" do
    Encoding.default_external = "UTF-8"
    @s.send(@method, "abc").encoding.should == Encoding::UTF_8
  end

  it "returns an ASCII-8BIT encoded string if any non-ascii bytes are present and default external is US-ASCII" do
    Encoding.default_external = "US-ASCII"
    x80 = [0x80].pack('C')
    @s.send(@method, "#{x80}abc").encoding.should == Encoding::ASCII_8BIT
  end

  it "returns a tainted String" do
    @s.send(@method, "abc").tainted?.should be_true
  end
end

describe "C-API String function" do
  before :each do
    @s = CApiStringSpecs.new
    @external = Encoding.default_external
    @internal = Encoding.default_internal
  end

  after :each do
    Encoding.default_external = @external
    Encoding.default_internal = @internal
  end

  describe "rb_str_length" do
    it "returns the string's length" do
      @s.rb_str_length("dewdrops").should == 8
    end

    it "counts characters in multi byte encodings" do
      @s.rb_str_length("düwdrops").should == 8
    end
  end

  describe "rb_str_equal" do
    it "compares two same strings" do
      s = "hello"
      @s.rb_str_equal(s, "hello").should be_true
    end

    it "compares two different strings" do
      s = "hello"
      @s.rb_str_equal(s, "hella").should be_false
    end
  end

  describe "rb_external_str_new" do
    it_behaves_like :rb_external_str_new, :rb_external_str_new
  end

  describe "rb_external_str_new_cstr" do
    it_behaves_like :rb_external_str_new, :rb_external_str_new_cstr
  end

  describe "rb_external_str_new_with_enc" do
    it "returns a String in the specified encoding" do
      s = @s.rb_external_str_new_with_enc("abc", 3, Encoding::UTF_8)
      s.encoding.should == Encoding::UTF_8
    end

    it "returns an ASCII-8BIT encoded String if any non-ascii bytes are present and the specified encoding is US-ASCII" do
      x80 = [0x80].pack('C')
      s = @s.rb_external_str_new_with_enc("#{x80}abc", 4, Encoding::US_ASCII)
      s.encoding.should == Encoding::ASCII_8BIT
    end


#     it "transcodes a String to Encoding.default_internal if it is set" do
#       Encoding.default_internal = Encoding::EUC_JP
#
#  -      a = "\xE3\x81\x82\xe3\x82\x8c".force_encoding("utf-8")
#  +      a = [0xE3, 0x81, 0x82, 0xe3, 0x82, 0x8c].pack('C6').force_encoding("utf-8")
#         s = @s.rb_external_str_new_with_enc(a, a.bytesize, Encoding::UTF_8)
#  -
#  -      s.should == "\xA4\xA2\xA4\xEC".force_encoding("euc-jp")
#  +      x = [0xA4, 0xA2, 0xA4, 0xEC].pack('C4')#.force_encoding('ascii-8bit')
#  +      s.should == x
#         s.encoding.should equal(Encoding::EUC_JP)
#     end

    it "transcodes a String to Encoding.default_internal if it is set" do
      Encoding.default_internal = Encoding::EUC_JP

      a = [0xE3, 0x81, 0x82, 0xe3, 0x82, 0x8c].pack('C6').force_encoding("utf-8")
      s = @s.rb_external_str_new_with_enc(a, a.bytesize, Encoding::UTF_8)
      x = [0xA4, 0xA2, 0xA4, 0xEC].pack('C4').force_encoding('euc-jp')
      s.should == x
      s.encoding.should equal(Encoding::EUC_JP)
    end

    it "returns a tainted String" do
      s = @s.rb_external_str_new_with_enc("abc", 3, Encoding::US_ASCII)
      s.tainted?.should be_true
    end
  end

  describe "rb_locale_str_new" do
    it "returns a String with 'locale' encoding" do
      s = @s.rb_locale_str_new("abc", 3)
      s.should == "abc".force_encoding(Encoding.find("locale"))
      s.encoding.should equal(Encoding.find("locale"))
    end
  end

  describe "rb_locale_str_new_cstr" do
    it "returns a String with 'locale' encoding" do
      s = @s.rb_locale_str_new_cstr("abc")
      s.should == "abc".force_encoding(Encoding.find("locale"))
      s.encoding.should equal(Encoding.find("locale"))
    end
  end

  describe "rb_str_conv_enc" do
    it "returns the original String when to encoding is not specified" do
      a = "abc".force_encoding("us-ascii")
      @s.rb_str_conv_enc(a, Encoding::US_ASCII, nil).should equal(a)
    end

    it "returns the original String if a transcoding error occurs" do
      a = [0xEE].pack('C').force_encoding("utf-8")
      @s.rb_str_conv_enc(a, Encoding::UTF_8, Encoding::EUC_JP).should equal(a)
    end

    it "returns a transcoded String" do
      a = "\xE3\x81\x82\xE3\x82\x8C".force_encoding("utf-8")
      result = @s.rb_str_conv_enc(a, Encoding::UTF_8, Encoding::EUC_JP)
      x = [0xA4, 0xA2, 0xA4, 0xEC].pack('C4').force_encoding('utf-8')
      result.should == x.force_encoding("euc-jp")
      result.encoding.should equal(Encoding::EUC_JP)
    end

    describe "when the String encoding is equal to the destination encoding" do
      it "returns the original String" do
        a = "abc".force_encoding("us-ascii")
        @s.rb_str_conv_enc(a, Encoding::US_ASCII, Encoding::US_ASCII).should equal(a)
      end

      it "returns the original String if the destination encoding is ASCII compatible and the String has no high bits set" do
        a = "abc".encode("us-ascii")
        @s.rb_str_conv_enc(a, Encoding::UTF_8, Encoding::US_ASCII).should equal(a)
      end

      it "returns the origin String if the destination encoding is ASCII-8BIT" do
        a = "abc".force_encoding("ascii-8bit")
        @s.rb_str_conv_enc(a, Encoding::US_ASCII, Encoding::ASCII_8BIT).should equal(a)
      end
    end
  end

  describe "rb_str_conv_enc_opts" do
    it "returns the original String when to encoding is not specified" do
      a = "abc".force_encoding("us-ascii")
      @s.rb_str_conv_enc_opts(a, Encoding::US_ASCII, nil, 0, nil).should equal(a)
    end

    it "returns the original String if a transcoding error occurs" do
      a = [0xEE].pack('C').force_encoding("utf-8")
      @s.rb_str_conv_enc_opts(a, Encoding::UTF_8,
                              Encoding::EUC_JP, 0, nil).should equal(a)
    end

    it "returns a transcoded String" do
      a = "\xE3\x81\x82\xE3\x82\x8C".force_encoding("utf-8")
      result = @s.rb_str_conv_enc_opts(a, Encoding::UTF_8, Encoding::EUC_JP, 0, nil)
      x = [0xA4, 0xA2, 0xA4, 0xEC].pack('C4').force_encoding('utf-8')
      result.should == x.force_encoding("euc-jp")
      result.encoding.should equal(Encoding::EUC_JP)
    end

    describe "when the String encoding is equal to the destination encoding" do
      it "returns the original String" do
        a = "abc".force_encoding("us-ascii")
        @s.rb_str_conv_enc_opts(a, Encoding::US_ASCII,
                                Encoding::US_ASCII, 0, nil).should equal(a)
      end

      it "returns the original String if the destination encoding is ASCII compatible and the String has no high bits set" do
        a = "abc".encode("us-ascii")
        @s.rb_str_conv_enc_opts(a, Encoding::UTF_8,
                                Encoding::US_ASCII, 0, nil).should equal(a)
      end

      it "returns the origin String if the destination encoding is ASCII-8BIT" do
        a = "abc".force_encoding("ascii-8bit")
        @s.rb_str_conv_enc_opts(a, Encoding::US_ASCII,
                                Encoding::ASCII_8BIT, 0, nil).should equal(a)
      end
    end
  end

  describe "rb_str_export" do
    it "returns the original String with the external encoding" do
      Encoding.default_external = Encoding::ISO_8859_1
      s = @s.rb_str_export("Hëllo")
      s.encoding.should equal(Encoding::ISO_8859_1)
    end
  end

  describe "rb_str_export_locale" do
    it "returns the original String with the locale encoding" do
      s = @s.rb_str_export_locale("abc")
      s.should == "abc".force_encoding(Encoding.find("locale"))
      s.encoding.should equal(Encoding.find("locale"))
    end
  end

  describe "rb_sprintf" do
    it "replaces the parts like sprintf" do
      @s.rb_sprintf1("Awesome %s is replaced", "string").should == "Awesome string is replaced"
      @s.rb_sprintf1("%s", "TestFoobarTest").should == "TestFoobarTest"
    end

    it "accepts multiple arguments" do
      s = "Awesome %s is here with %s"
      @s.rb_sprintf2(s, "string", "content").should == "Awesome string is here with content"
    end
  end

  describe "rb_vsprintf" do
    it "returns a formatted String from a variable number of arguments" do
      s = @s.rb_vsprintf("%s, %d, %.2f", "abc", 42, 2.7);
      s.should == "abc, 42, 2.70"
    end
  end

  describe "rb_String" do
    it "returns the passed argument if it is a string" do
      @s.rb_String("a").should == "a"
    end

    it "tries to convert the passed argument to a string by calling #to_str first" do
      @s.rb_String(ValidTostrTest.new).should == "ruby"
    end

    it "raises a TypeError if #to_str does not return a string" do
      lambda { @s.rb_String(InvalidTostrTest.new) }.should raise_error(TypeError)
    end

    it "tries to convert the passed argument to a string by calling #to_s" do
      @s.rb_String({"bar" => "foo"}).should == '{"bar"=>"foo"}'
    end
  end

  describe "rb_string_value_cstr" do
    it "returns a non-null pointer for a simple string" do
      @s.rb_string_value_cstr("Hello").should == true
    end

    it "returns a non-null pointer for a UTF-16 string" do
      @s.rb_string_value_cstr("Hello".encode('UTF-16BE')).should == true
    end

    it "raises an error if a string contains a null" do
      lambda { @s.rb_string_value_cstr("Hello\0 with a null.") }.should raise_error(ArgumentError)
    end

    it "raises an error if a UTF-16 string contains a null" do
      lambda { @s.rb_string_value_cstr("Hello\0 with a null.".encode('UTF-16BE')) }.should raise_error(ArgumentError)
    end

  end
end