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ruby--ruby/spec/ruby/core/string/shared/succ.rb
Jeremy Evans 58325daae3 Make String methods return String instances when called on a subclass instance
This modifies the following String methods to return String instances
instead of subclass instances:

* String#*
* String#capitalize
* String#center
* String#chomp
* String#chop
* String#delete
* String#delete_prefix
* String#delete_suffix
* String#downcase
* String#dump
* String#each/#each_line
* String#gsub
* String#ljust
* String#lstrip
* String#partition
* String#reverse
* String#rjust
* String#rpartition
* String#rstrip
* String#scrub
* String#slice!
* String#slice/#[]
* String#split
* String#squeeze
* String#strip
* String#sub
* String#succ/#next
* String#swapcase
* String#tr
* String#tr_s
* String#upcase

This also fixes a bug in String#swapcase where it would return the
receiver instead of a copy of the receiver if the receiver was the
empty string.

Some string methods were left to return subclass instances:

* String#+@
* String#-@

Both of these methods will return the receiver (subclass instance)
in some cases, so it is best to keep the returned class consistent.

Fixes [#10845]
2020-11-20 16:30:23 -08:00

100 lines
3.5 KiB
Ruby

# -*- encoding: binary -*-
describe :string_succ, shared: true do
it "returns an empty string for empty strings" do
"".send(@method).should == ""
end
it "returns the successor by increasing the rightmost alphanumeric (digit => digit, letter => letter with same case)" do
"abcd".send(@method).should == "abce"
"THX1138".send(@method).should == "THX1139"
"<<koala>>".send(@method).should == "<<koalb>>"
"==A??".send(@method).should == "==B??"
end
it "increases non-alphanumerics (via ascii rules) if there are no alphanumerics" do
"***".send(@method).should == "**+"
"**`".send(@method).should == "**a"
end
it "increases the next best alphanumeric (jumping over non-alphanumerics) if there is a carry" do
"dz".send(@method).should == "ea"
"HZ".send(@method).should == "IA"
"49".send(@method).should == "50"
"izz".send(@method).should == "jaa"
"IZZ".send(@method).should == "JAA"
"699".send(@method).should == "700"
"6Z99z99Z".send(@method).should == "7A00a00A"
"1999zzz".send(@method).should == "2000aaa"
"NZ/[]ZZZ9999".send(@method).should == "OA/[]AAA0000"
end
it "increases the next best character if there is a carry for non-alphanumerics" do
"(\xFF".send(@method).should == ")\x00"
"`\xFF".send(@method).should == "a\x00"
"<\xFF\xFF".send(@method).should == "=\x00\x00"
end
it "adds an additional character (just left to the last increased one) if there is a carry and no character left to increase" do
"z".send(@method).should == "aa"
"Z".send(@method).should == "AA"
"9".send(@method).should == "10"
"zz".send(@method).should == "aaa"
"ZZ".send(@method).should == "AAA"
"99".send(@method).should == "100"
"9Z99z99Z".send(@method).should == "10A00a00A"
"ZZZ9999".send(@method).should == "AAAA0000"
"/[]9999".send(@method).should == "/[]10000"
"/[]ZZZ9999".send(@method).should == "/[]AAAA0000"
"Z/[]ZZZ9999".send(@method).should == "AA/[]AAA0000"
# non-alphanumeric cases
"\xFF".send(@method).should == "\x01\x00"
"\xFF\xFF".send(@method).should == "\x01\x00\x00"
end
ruby_version_is ''...'3.0' do
it "returns subclass instances when called on a subclass" do
StringSpecs::MyString.new("").send(@method).should be_an_instance_of(StringSpecs::MyString)
StringSpecs::MyString.new("a").send(@method).should be_an_instance_of(StringSpecs::MyString)
StringSpecs::MyString.new("z").send(@method).should be_an_instance_of(StringSpecs::MyString)
end
end
ruby_version_is '3.0' do
it "returns String instances when called on a subclass" do
StringSpecs::MyString.new("").send(@method).should be_an_instance_of(String)
StringSpecs::MyString.new("a").send(@method).should be_an_instance_of(String)
StringSpecs::MyString.new("z").send(@method).should be_an_instance_of(String)
end
end
ruby_version_is ''...'2.7' do
it "taints the result if self is tainted" do
["", "a", "z", "Z", "9", "\xFF", "\xFF\xFF"].each do |s|
s.taint.send(@method).should.tainted?
end
end
end
end
describe :string_succ_bang, shared: true do
it "is equivalent to succ, but modifies self in place (still returns self)" do
["", "abcd", "THX1138"].each do |s|
r = s.dup.send(@method)
s.send(@method).should equal(s)
s.should == r
end
end
it "raises a FrozenError if self is frozen" do
-> { "".freeze.send(@method) }.should raise_error(FrozenError)
-> { "abcd".freeze.send(@method) }.should raise_error(FrozenError)
end
end