1 files changed, 88 insertions, 0 deletions
diff --git a/spec/ruby/core/string/shared/succ.rb b/spec/ruby/core/string/shared/succ.rb
new file mode 100644
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+++ b/spec/ruby/core/string/shared/succ.rb
@@ -0,0 +1,88 @@
+# -*- 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
+
+  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
+
+  it "taints the result if self is tainted" do
+    ["", "a", "z", "Z", "9", "\xFF", "\xFF\xFF"].each do |s|
+      s.taint.send(@method).tainted?.should == true
+    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 RuntimeError if self is frozen" do
+    lambda { "".freeze.send(@method)     }.should raise_error(RuntimeError)
+    lambda { "abcd".freeze.send(@method) }.should raise_error(RuntimeError)
+  end
+end