# -*- encoding: utf-8 -*-
require File.expand_path('../../../spec_helper', __FILE__)
require File.expand_path('../fixtures/classes.rb', __FILE__)

describe "String#gsub with pattern and replacement" do

  before :each do
    @kcode = $KCODE
  end

  after :each do
    $KCODE = @kcode
  end

  it "inserts the replacement around every character when the pattern collapses" do
    "hello".gsub(//, ".").should == ".h.e.l.l.o."
  end

  it "respects $KCODE when the pattern collapses" do
    str = "こにちわ"
    reg = %r!!

    $KCODE = "utf-8"
    str.gsub(reg, ".").should == ".こ.に.ち.わ."
  end

  it "doesn't freak out when replacing ^" do
    "Text\n".gsub(/^/, ' ').should == " Text\n"
    "Text\nFoo".gsub(/^/, ' ').should == " Text\n Foo"
  end

  it "returns a copy of self with all occurrences of pattern replaced with replacement" do
    "hello".gsub(/[aeiou]/, '*').should == "h*ll*"

    str = "hello homely world. hah!"
    str.gsub(/\Ah\S+\s*/, "huh? ").should == "huh? homely world. hah!"
  end

  it "ignores a block if supplied" do
    "food".gsub(/f/, "g") { "w" }.should == "good"
  end

  it "supports \\G which matches at the beginning of the remaining (non-matched) string" do
    str = "hello homely world. hah!"
    str.gsub(/\Gh\S+\s*/, "huh? ").should == "huh? huh? world. hah!"
  end

  it "supports /i for ignoring case" do
    str = "Hello. How happy are you?"
    str.gsub(/h/i, "j").should == "jello. jow jappy are you?"
    str.gsub(/H/i, "j").should == "jello. jow jappy are you?"
  end

  it "doesn't interpret regexp metacharacters if pattern is a string" do
    "12345".gsub('\d', 'a').should == "12345"
    '\d'.gsub('\d', 'a').should == "a"
  end

  it "replaces \\1 sequences with the regexp's corresponding capture" do
    str = "hello"

    str.gsub(/([aeiou])/, '<\1>').should == "h<e>ll<o>"
    str.gsub(/(.)/, '\1\1').should == "hheelllloo"

    str.gsub(/.(.?)/, '<\0>(\1)').should == "<he>(e)<ll>(l)<o>()"

    str.gsub(/.(.)+/, '\1').should == "o"

    str = "ABCDEFGHIJKLabcdefghijkl"
    re = /#{"(.)" * 12}/
    str.gsub(re, '\1').should == "Aa"
    str.gsub(re, '\9').should == "Ii"
    # Only the first 9 captures can be accessed in MRI
    str.gsub(re, '\10').should == "A0a0"
  end

  it "treats \\1 sequences without corresponding captures as empty strings" do
    str = "hello!"

    str.gsub("", '<\1>').should == "<>h<>e<>l<>l<>o<>!<>"
    str.gsub("h", '<\1>').should == "<>ello!"

    str.gsub(//, '<\1>').should == "<>h<>e<>l<>l<>o<>!<>"
    str.gsub(/./, '\1\2\3').should == ""
    str.gsub(/.(.{20})?/, '\1').should == ""
  end

  it "replaces \\& and \\0 with the complete match" do
    str = "hello!"

    str.gsub("", '<\0>').should == "<>h<>e<>l<>l<>o<>!<>"
    str.gsub("", '<\&>').should == "<>h<>e<>l<>l<>o<>!<>"
    str.gsub("he", '<\0>').should == "<he>llo!"
    str.gsub("he", '<\&>').should == "<he>llo!"
    str.gsub("l", '<\0>').should == "he<l><l>o!"
    str.gsub("l", '<\&>').should == "he<l><l>o!"

    str.gsub(//, '<\0>').should == "<>h<>e<>l<>l<>o<>!<>"
    str.gsub(//, '<\&>').should == "<>h<>e<>l<>l<>o<>!<>"
    str.gsub(/../, '<\0>').should == "<he><ll><o!>"
    str.gsub(/../, '<\&>').should == "<he><ll><o!>"
    str.gsub(/(.)./, '<\0>').should == "<he><ll><o!>"
  end

  it "replaces \\` with everything before the current match" do
    str = "hello!"

    str.gsub("", '<\`>').should == "<>h<h>e<he>l<hel>l<hell>o<hello>!<hello!>"
    str.gsub("h", '<\`>').should == "<>ello!"
    str.gsub("l", '<\`>').should == "he<he><hel>o!"
    str.gsub("!", '<\`>').should == "hello<hello>"

    str.gsub(//, '<\`>').should == "<>h<h>e<he>l<hel>l<hell>o<hello>!<hello!>"
    str.gsub(/../, '<\`>').should == "<><he><hell>"
  end

  it "replaces \\' with everything after the current match" do
    str = "hello!"

    str.gsub("", '<\\\'>').should == "<hello!>h<ello!>e<llo!>l<lo!>l<o!>o<!>!<>"
    str.gsub("h", '<\\\'>').should == "<ello!>ello!"
    str.gsub("ll", '<\\\'>').should == "he<o!>o!"
    str.gsub("!", '<\\\'>').should == "hello<>"

    str.gsub(//, '<\\\'>').should == "<hello!>h<ello!>e<llo!>l<lo!>l<o!>o<!>!<>"
    str.gsub(/../, '<\\\'>').should == "<llo!><o!><>"
  end

  it "replaces \\+ with the last paren that actually matched" do
    str = "hello!"

    str.gsub(/(.)(.)/, '\+').should == "el!"
    str.gsub(/(.)(.)+/, '\+').should == "!"
    str.gsub(/(.)()/, '\+').should == ""
    str.gsub(/(.)(.{20})?/, '<\+>').should == "<h><e><l><l><o><!>"

    str = "ABCDEFGHIJKLabcdefghijkl"
    re = /#{"(.)" * 12}/
    str.gsub(re, '\+').should == "Ll"
  end

  it "treats \\+ as an empty string if there was no captures" do
    "hello!".gsub(/./, '\+').should == ""
  end

  it "maps \\\\ in replacement to \\" do
    "hello".gsub(/./, '\\\\').should == '\\' * 5
  end

  it "leaves unknown \\x escapes in replacement untouched" do
    "hello".gsub(/./, '\\x').should == '\\x' * 5
    "hello".gsub(/./, '\\y').should == '\\y' * 5
  end

  it "leaves \\ at the end of replacement untouched" do
    "hello".gsub(/./, 'hah\\').should == 'hah\\' * 5
  end

  it "taints the result if the original string or replacement is tainted" do
    hello = "hello"
    hello_t = "hello"
    a = "a"
    a_t = "a"
    empty = ""
    empty_t = ""

    hello_t.taint; a_t.taint; empty_t.taint

    hello_t.gsub(/./, a).tainted?.should == true
    hello_t.gsub(/./, empty).tainted?.should == true

    hello.gsub(/./, a_t).tainted?.should == true
    hello.gsub(/./, empty_t).tainted?.should == true
    hello.gsub(//, empty_t).tainted?.should == true

    hello.gsub(//.taint, "foo").tainted?.should == false
  end

  ruby_version_is "1.9" do
    it "handles pattern collapse without $KCODE" do
      str = "こにちわ"
      reg = %r!!
      str.gsub(reg, ".").should == ".こ.に.ち.わ."
    end

    it "untrusts the result if the original string or replacement is untrusted" do
      hello = "hello"
      hello_t = "hello"
      a = "a"
      a_t = "a"
      empty = ""
      empty_t = ""

      hello_t.untrust; a_t.untrust; empty_t.untrust

      hello_t.gsub(/./, a).untrusted?.should == true
      hello_t.gsub(/./, empty).untrusted?.should == true

      hello.gsub(/./, a_t).untrusted?.should == true
      hello.gsub(/./, empty_t).untrusted?.should == true
      hello.gsub(//, empty_t).untrusted?.should == true

      hello.gsub(//.untrust, "foo").untrusted?.should == false
    end
  end

  it "tries to convert pattern to a string using to_str" do
    pattern = mock('.')
    def pattern.to_str() "." end

    "hello.".gsub(pattern, "!").should == "hello!"
  end

  it "raises a TypeError when pattern can't be converted to a string" do
    lambda { "hello".gsub([], "x")            }.should raise_error(TypeError)
    lambda { "hello".gsub(Object.new, "x")    }.should raise_error(TypeError)
    lambda { "hello".gsub(nil, "x")           }.should raise_error(TypeError)
  end

  it "tries to convert replacement to a string using to_str" do
    replacement = mock('hello_replacement')
    def replacement.to_str() "hello_replacement" end

    "hello".gsub(/hello/, replacement).should == "hello_replacement"
  end

  it "raises a TypeError when replacement can't be converted to a string" do
    lambda { "hello".gsub(/[aeiou]/, [])            }.should raise_error(TypeError)
    lambda { "hello".gsub(/[aeiou]/, Object.new)    }.should raise_error(TypeError)
    lambda { "hello".gsub(/[aeiou]/, nil)           }.should raise_error(TypeError)
  end

  it "returns subclass instances when called on a subclass" do
    StringSpecs::MyString.new("").gsub(//, "").should be_kind_of(StringSpecs::MyString)
    StringSpecs::MyString.new("").gsub(/foo/, "").should be_kind_of(StringSpecs::MyString)
    StringSpecs::MyString.new("foo").gsub(/foo/, "").should be_kind_of(StringSpecs::MyString)
    StringSpecs::MyString.new("foo").gsub("foo", "").should be_kind_of(StringSpecs::MyString)
  end

  # Note: $~ cannot be tested because mspec messes with it

  it "sets $~ to MatchData of last match and nil when there's none" do
    'hello.'.gsub('hello', 'x')
    $~[0].should == 'hello'

    'hello.'.gsub('not', 'x')
    $~.should == nil

    'hello.'.gsub(/.(.)/, 'x')
    $~[0].should == 'o.'

    'hello.'.gsub(/not/, 'x')
    $~.should == nil
  end
end

ruby_version_is "1.9" do

  describe "String#gsub with pattern and Hash" do

    it "returns a copy of self with all occurrences of pattern replaced with the value of the corresponding hash key" do
      "hello".gsub(/./, 'l' => 'L').should == "LL"
      "hello!".gsub(/(.)(.)/, 'he' => 'she ', 'll' => 'said').should == 'she said'
      "hello".gsub('l', 'l' => 'el').should == 'heelelo'
    end

    it "ignores keys that don't correspond to matches" do
      "hello".gsub(/./, 'z' => 'L', 'h' => 'b', 'o' => 'ow').should == "bow"
    end

    it "returns an empty string if the pattern matches but the hash specifies no replacements" do
      "hello".gsub(/./, 'z' => 'L').should == ""
    end

    it "ignores non-String keys" do
      "hello".gsub(/(ll)/, 'll' => 'r', :ll => 'z').should == "hero"
    end

    it "uses a key's value as many times as needed" do
      "food".gsub(/o/, 'o' => '0').should == "f00d"
    end

    it "uses the hash's default value for missing keys" do
      hsh = new_hash
      hsh.default='?'
      hsh['o'] = '0'
      "food".gsub(/./, hsh).should == "?00?"
    end

    it "coerces the hash values with #to_s" do
      hsh = new_hash
      hsh.default=[]
      hsh['o'] = 0
      obj = mock('!')
      obj.should_receive(:to_s).and_return('!')
      hsh['!'] = obj
      "food!".gsub(/./, hsh).should == "[]00[]!"
    end

    it "uses the hash's value set from default_proc for missing keys" do
      hsh = new_hash
      hsh.default_proc = lambda { |k,v| 'lamb' }
      "food!".gsub(/./, hsh).should == "lamblamblamblamblamb"
    end

    it "sets $~ to MatchData of last match and nil when there's none for access from outside" do
      'hello.'.gsub('l', 'l' => 'L')
      $~.begin(0).should == 3
      $~[0].should == 'l'

      'hello.'.gsub('not', 'ot' => 'to')
      $~.should == nil

      'hello.'.gsub(/.(.)/, 'o' => ' hole')
      $~[0].should == 'o.'

      'hello.'.gsub(/not/, 'z' => 'glark')
      $~.should == nil
    end

    it "doesn't interpolate special sequences like \\1 for the block's return value" do
      repl = '\& \0 \1 \` \\\' \+ \\\\ foo'
      "hello".gsub(/(.+)/, 'hello' => repl ).should == repl
    end

    it "untrusts the result if the original string is untrusted" do
      str = "Ghana".untrust
      str.gsub(/[Aa]na/, 'ana' => '').untrusted?.should be_true
    end

    it "untrusts the result if a hash value is untrusted" do
      str = "Ghana"
      str.gsub(/a$/, 'a' => 'di'.untrust).untrusted?.should be_true
    end

    it "taints the result if the original string is tainted" do
      str = "Ghana".taint
      str.gsub(/[Aa]na/, 'ana' => '').tainted?.should be_true
    end

    it "taints the result if a hash value is tainted" do
      str = "Ghana"
      str.gsub(/a$/, 'a' => 'di'.taint).tainted?.should be_true
    end

  end

  describe "String#gsub! with pattern and Hash" do

    it "returns self with all occurrences of pattern replaced with the value of the corresponding hash key" do
      "hello".gsub!(/./, 'l' => 'L').should == "LL"
      "hello!".gsub!(/(.)(.)/, 'he' => 'she ', 'll' => 'said').should == 'she said'
      "hello".gsub!('l', 'l' => 'el').should == 'heelelo'
    end

    it "ignores keys that don't correspond to matches" do
      "hello".gsub!(/./, 'z' => 'L', 'h' => 'b', 'o' => 'ow').should == "bow"
    end

    it "replaces self with an empty string if the pattern matches but the hash specifies no replacements" do
      "hello".gsub!(/./, 'z' => 'L').should == ""
    end

    it "ignores non-String keys" do
      "hello".gsub!(/(ll)/, 'll' => 'r', :ll => 'z').should == "hero"
    end

    it "uses a key's value as many times as needed" do
      "food".gsub!(/o/, 'o' => '0').should == "f00d"
    end

    it "uses the hash's default value for missing keys" do
      hsh = new_hash
      hsh.default='?'
      hsh['o'] = '0'
      "food".gsub!(/./, hsh).should == "?00?"
    end

    it "coerces the hash values with #to_s" do
      hsh = new_hash
      hsh.default=[]
      hsh['o'] = 0
      obj = mock('!')
      obj.should_receive(:to_s).and_return('!')
      hsh['!'] = obj
      "food!".gsub!(/./, hsh).should == "[]00[]!"
    end

    it "uses the hash's value set from default_proc for missing keys" do
      hsh = new_hash
      hsh.default_proc = lambda { |k,v| 'lamb' }
      "food!".gsub!(/./, hsh).should == "lamblamblamblamblamb"
    end

    it "sets $~ to MatchData of last match and nil when there's none for access from outside" do
      'hello.'.gsub!('l', 'l' => 'L')
      $~.begin(0).should == 3
      $~[0].should == 'l'

      'hello.'.gsub!('not', 'ot' => 'to')
      $~.should == nil

      'hello.'.gsub!(/.(.)/, 'o' => ' hole')
      $~[0].should == 'o.'

      'hello.'.gsub!(/not/, 'z' => 'glark')
      $~.should == nil
    end

    it "doesn't interpolate special sequences like \\1 for the block's return value" do
      repl = '\& \0 \1 \` \\\' \+ \\\\ foo'
      "hello".gsub!(/(.+)/, 'hello' => repl ).should == repl
    end

    it "keeps untrusted state" do
      str = "Ghana".untrust
      str.gsub!(/[Aa]na/, 'ana' => '').untrusted?.should be_true
    end

    it "untrusts self if a hash value is untrusted" do
      str = "Ghana"
      str.gsub!(/a$/, 'a' => 'di'.untrust).untrusted?.should be_true
    end

    it "keeps tainted state" do
      str = "Ghana".taint
      str.gsub!(/[Aa]na/, 'ana' => '').tainted?.should be_true
    end

    it "taints self if a hash value is tainted" do
      str = "Ghana"
      str.gsub!(/a$/, 'a' => 'di'.taint).tainted?.should be_true
    end

  end
end

describe "String#gsub with pattern and block" do
  it "returns a copy of self with all occurrences of pattern replaced with the block's return value" do
    "hello".gsub(/./) { |s| s.succ + ' ' }.should == "i f m m p "
    "hello!".gsub(/(.)(.)/) { |*a| a.inspect }.should == '["he"]["ll"]["o!"]'
    "hello".gsub('l') { 'x'}.should == 'hexxo'
  end

  it "sets $~ for access from the block" do
    str = "hello"
    str.gsub(/([aeiou])/) { "<#{$~[1]}>" }.should == "h<e>ll<o>"
    str.gsub(/([aeiou])/) { "<#{$1}>" }.should == "h<e>ll<o>"
    str.gsub("l") { "<#{$~[0]}>" }.should == "he<l><l>o"

    offsets = []

    str.gsub(/([aeiou])/) do
      md = $~
      md.string.should == str
      offsets << md.offset(0)
      str
    end.should == "hhellollhello"

    offsets.should == [[1, 2], [4, 5]]
  end

  it "restores $~ after leaving the block" do
    [/./, "l"].each do |pattern|
      old_md = nil
      "hello".gsub(pattern) do
        old_md = $~
        "ok".match(/./)
        "x"
      end

      $~[0].should == old_md[0]
      $~.string.should == "hello"
    end
  end

  it "sets $~ to MatchData of last match and nil when there's none for access from outside" do
    'hello.'.gsub('l') { 'x' }
    $~.begin(0).should == 3
    $~[0].should == 'l'

    'hello.'.gsub('not') { 'x' }
    $~.should == nil

    'hello.'.gsub(/.(.)/) { 'x' }
    $~[0].should == 'o.'

    'hello.'.gsub(/not/) { 'x' }
    $~.should == nil
  end

  ruby_version_is ""..."1.9" do
    it "raises a RuntimeError if the string is modified while substituting" do
      str = "hello"
      lambda { str.gsub(//) { str[0] = 'x' } }.should raise_error(RuntimeError)
    end
  end

  it "doesn't interpolate special sequences like \\1 for the block's return value" do
    repl = '\& \0 \1 \` \\\' \+ \\\\ foo'
    "hello".gsub(/(.+)/) { repl }.should == repl
  end

  it "converts the block's return value to a string using to_s" do
    replacement = mock('hello_replacement')
    def replacement.to_s() "hello_replacement" end

    "hello".gsub(/hello/) { replacement }.should == "hello_replacement"

    obj = mock('ok')
    def obj.to_s() "ok" end

    "hello".gsub(/.+/) { obj }.should == "ok"
  end

  ruby_version_is "1.9" do
    it "untrusts the result if the original string or replacement is untrusted" do
      hello = "hello"
      hello_t = "hello"
      a = "a"
      a_t = "a"
      empty = ""
      empty_t = ""

      hello_t.untrust; a_t.untrust; empty_t.untrust

      hello_t.gsub(/./) { a }.untrusted?.should == true
      hello_t.gsub(/./) { empty }.untrusted?.should == true

      hello.gsub(/./) { a_t }.untrusted?.should == true
      hello.gsub(/./) { empty_t }.untrusted?.should == true
      hello.gsub(//) { empty_t }.untrusted?.should == true

      hello.gsub(//.untrust) { "foo" }.untrusted?.should == false
    end
  end

  ruby_version_is "1.9" do
    it "uses the compatible encoding if they are compatible" do
      s  = "hello"
      s2 = "#{195.chr}#{192.chr}#{195.chr}"

      s.gsub(/l/) { |bar| 195.chr }.encoding.should == Encoding::ASCII_8BIT
      s2.gsub("#{192.chr}") { |bar| "hello" }.encoding.should == Encoding::ASCII_8BIT
    end

    it "raises an Encoding::CompatibilityError if the encodings are not compatible" do
      s = "hllëllo"
      s2 = "hellö"

      lambda { s.gsub(/l/) { |bar| "Русский".force_encoding("iso-8859-5") } }.should raise_error(Encoding::CompatibilityError)
      lambda { s2.gsub(/l/) { |bar| "Русский".force_encoding("iso-8859-5") } }.should raise_error(Encoding::CompatibilityError)
    end

    it "replaces the incompatible part properly even if the encodings are not compatible" do
      s = "hllëllo"

      s.gsub(/ë/) { |bar| "Русский".force_encoding("iso-8859-5") }.encoding.should == Encoding::ISO_8859_5
    end
  end
end

describe "String#gsub! with pattern and replacement" do
  it "modifies self in place and returns self" do
    a = "hello"
    a.gsub!(/[aeiou]/, '*').should equal(a)
    a.should == "h*ll*"
  end

  it "taints self if replacement is tainted" do
    a = "hello"
    a.gsub!(/./.taint, "foo").tainted?.should == false
    a.gsub!(/./, "foo".taint).tainted?.should == true
  end

  ruby_version_is "1.9" do
    it "untrusts self if replacement is untrusted" do
      a = "hello"
      a.gsub!(/./.untrust, "foo").untrusted?.should == false
      a.gsub!(/./, "foo".untrust).untrusted?.should == true
    end
  end

  it "returns nil if no modifications were made" do
    a = "hello"
    a.gsub!(/z/, '*').should == nil
    a.gsub!(/z/, 'z').should == nil
    a.should == "hello"
  end

  ruby_version_is ""..."1.9" do
    it "does not raise an error if the frozen string would not be modified" do
      s = "hello"
      s.freeze

      s.gsub!(/ROAR/, "x").should be_nil
    end

    it "raises a TypeError if the frozen string would be modified" do
      s = "hello"
      s.freeze

      lambda { s.gsub!(/e/, "e")       }.should raise_error(TypeError)
      lambda { s.gsub!(/[aeiou]/, '*') }.should raise_error(TypeError)
    end
  end

  # See [ruby-core:23666]
  ruby_version_is "1.9" do
    it "raises a RuntimeError when self is frozen" do
      s = "hello"
      s.freeze

      lambda { s.gsub!(/ROAR/, "x")    }.should raise_error(RuntimeError)
      lambda { s.gsub!(/e/, "e")       }.should raise_error(RuntimeError)
      lambda { s.gsub!(/[aeiou]/, '*') }.should raise_error(RuntimeError)
    end
  end
end

describe "String#gsub! with pattern and block" do
  it "modifies self in place and returns self" do
    a = "hello"
    a.gsub!(/[aeiou]/) { '*' }.should equal(a)
    a.should == "h*ll*"
  end

  it "taints self if block's result is tainted" do
    a = "hello"
    a.gsub!(/./.taint) { "foo" }.tainted?.should == false
    a.gsub!(/./) { "foo".taint }.tainted?.should == true
  end

  ruby_version_is "1.9" do
    it "untrusts self if block's result is untrusted" do
      a = "hello"
      a.gsub!(/./.untrust) { "foo" }.untrusted?.should == false
      a.gsub!(/./) { "foo".untrust }.untrusted?.should == true
    end
  end

  it "returns nil if no modifications were made" do
    a = "hello"
    a.gsub!(/z/) { '*' }.should == nil
    a.gsub!(/z/) { 'z' }.should == nil
    a.should == "hello"
  end

  ruby_version_is ""..."1.9" do
    it "does not raise an error if the frozen string would not be modified" do
      s = "hello"
      s.freeze

      s.gsub!(/ROAR/) { "x" }.should be_nil
    end

    deviates_on :rubinius do
      # MRI 1.8.x is inconsistent here, raising a TypeError when not passed
      # a block and a RuntimeError when passed a block. This is arguably a
      # bug in MRI. In 1.9, both situations raise a RuntimeError.
      it "raises a TypeError if the frozen string would be modified" do
        s = "hello"
        s.freeze

        lambda { s.gsub!(/e/)       { "e" } }.should raise_error(TypeError)
        lambda { s.gsub!(/[aeiou]/) { '*' } }.should raise_error(TypeError)
      end
    end

    not_compliant_on :rubinius do
      it "raises a RuntimeError if the frozen string would be modified" do
        s = "hello"
        s.freeze

        lambda { s.gsub!(/e/)       { "e" } }.should raise_error(RuntimeError)
        lambda { s.gsub!(/[aeiou]/) { '*' } }.should raise_error(RuntimeError)
      end
    end
  end

  # See [ruby-core:23663]
  ruby_version_is "1.9" do
    it "raises a RuntimeError when self is frozen" do
      s = "hello"
      s.freeze

      lambda { s.gsub!(/ROAR/)    { "x" } }.should raise_error(RuntimeError)
      lambda { s.gsub!(/e/)       { "e" } }.should raise_error(RuntimeError)
      lambda { s.gsub!(/[aeiou]/) { '*' } }.should raise_error(RuntimeError)
    end
  end

  ruby_version_is "1.9" do
    it "uses the compatible encoding if they are compatible" do
      s  = "hello"
      s2 = "#{195.chr}#{192.chr}#{195.chr}"

      s.gsub!(/l/) { |bar| 195.chr }.encoding.should == Encoding::ASCII_8BIT
      s2.gsub!("#{192.chr}") { |bar| "hello" }.encoding.should == Encoding::ASCII_8BIT
    end

    it "raises an Encoding::CompatibilityError if the encodings are not compatible" do
      s = "hllëllo"
      s2 = "hellö"

      lambda { s.gsub!(/l/) { |bar| "Русский".force_encoding("iso-8859-5") } }.should raise_error(Encoding::CompatibilityError)
      lambda { s2.gsub!(/l/) { |bar| "Русский".force_encoding("iso-8859-5") } }.should raise_error(Encoding::CompatibilityError)
    end

    it "replaces the incompatible part properly even if the encodings are not compatible" do
      s = "hllëllo"

      s.gsub!(/ë/) { |bar| "Русский".force_encoding("iso-8859-5") }.encoding.should == Encoding::ISO_8859_5
    end
  end
end