1 files changed, 771 insertions, 0 deletions
diff --git a/spec/rubyspec/optional/capi/string_spec.rb b/spec/rubyspec/optional/capi/string_spec.rb
new file mode 100644
index 0000000000..ce0485e8af
--- /dev/null
+++ b/spec/rubyspec/optional/capi/string_spec.rb
@@ -0,0 +1,771 @@
+# encoding: utf-8
+require File.expand_path('../spec_helper', __FILE__)
+require File.expand_path('../../../shared/string/times', __FILE__)
+
+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 string's attributes visible in C code" do
+      @s.rb_str_set_len_RSTRING_LEN(@str, 4).should == 4
+    end
+  end
+
+  describe "rb_str_buf_new" do
+    it "returns the equivalent of an empty string" do
+      @s.rb_str_buf_new(10, nil).should == ""
+    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
+  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 "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
+  end
+
+  describe "rb_str_new2" do
+    it_behaves_like :rb_str_new2, :rb_str_new2
+  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
+  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.object_id.should_not == str2.object_id
+    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.object_id.should_not == str2.object_id
+    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_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, 65)
+      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 "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 "StringValue" do
+    it "does not call #to_str on a String" do
+      str = "genuine"
+      str.should_not_receive(:to_str)
+      @s.StringValue(str)
+    end
+
+    it "does not call #to_s on a String" do
+      str = "genuine"
+      str.should_not_receive(:to_str)
+      @s.StringValue(str)
+    end
+
+    it "calls #to_str on non-String objects" do
+      str = mock("fake")
+      str.should_receive(:to_str).and_return("wannabe")
+      @s.StringValue(str)
+    end
+
+    it "does not call #to_s on non-String objects" do
+      str = mock("fake")
+      str.should_not_receive(:to_s)
+      lambda { @s.StringValue(str) }.should raise_error(TypeError)
+    end
+  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 == s.hash
+    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
+end