Increase test coverage and coerce inputs to string

Where possible, coerce inputs to strings with StringValue rather than
raising a TypeError. This particularly impacts the relatively recent
RE2::Set API which was excessively strict about its arguments.

Add test coverage to all parts of the API, better covering edge cases
including how encoding is handled based on the encoding of the given
pattern.

ext/re2/re2.cc

@@ -312,7 +312,6 @@ static VALUE re2_scanner_scan(VALUE self) {
   original_input_size = c->input->size();
 
   for (i = 0; i < c->number_of_capturing_groups; i++) {
-    matches[i] = "";
     argv[i] = &matches[i];
     args[i] = &argv[i];
   }
@@ -1404,7 +1403,9 @@ static VALUE re2_Replace(VALUE self, VALUE str, VALUE pattern,
   UNUSED(self);
   re2_pattern *p;
 
-  /* Convert all the inputs to be pumped into RE2::Replace. */
+  /* Take a copy of str so it can be modified in-place by
+   * RE2::Replace.
+   */
   string str_as_string(StringValuePtr(str));
 
   /* Do the replacement. */
@@ -1440,7 +1441,9 @@ static VALUE re2_GlobalReplace(VALUE self, VALUE str, VALUE pattern,
                                VALUE rewrite) {
   UNUSED(self);
 
-  /* Convert all the inputs to be pumped into RE2::GlobalReplace. */
+  /* Take a copy of str so it can be modified in-place by
+   * RE2::GlobalReplace.
+   */
   re2_pattern *p;
   string str_as_string(StringValuePtr(str));
 
@@ -1579,11 +1582,12 @@ static VALUE re2_set_initialize(int argc, VALUE *argv, VALUE self) {
  *   set.add("def")    #=> 1
  */
 static VALUE re2_set_add(VALUE self, VALUE pattern) {
-  Check_Type(pattern, T_STRING);
+  StringValue(pattern);
   re2::StringPiece regex(RSTRING_PTR(pattern), RSTRING_LEN(pattern));
   std::string err;
   re2_set *s;
   Data_Get_Struct(self, re2_set, s);
+
   int index = s->set->Add(regex, &err);
   if (index < 0) {
     rb_raise(rb_eArgError, "str rejected by RE2::Set->Add(): %s", err.c_str());
@@ -1669,7 +1673,8 @@ static VALUE re2_set_match(int argc, VALUE *argv, VALUE self) {
   VALUE str, options, exception_option;
   bool raise_exception = true;
   rb_scan_args(argc, argv, "11", &str, &options);
-  Check_Type(str, T_STRING);
+
+  StringValue(str);
   re2::StringPiece data(RSTRING_PTR(str), RSTRING_LEN(str));
   std::vector<int> v;
   re2_set *s;

spec/kernel_spec.rb

@@ -1,13 +1,13 @@
 RSpec.describe Kernel do
-  describe "#RE2" do
+  describe ".RE2" do
     it "returns an RE2::Regexp instance given a pattern" do
       expect(RE2('w(o)(o)')).to be_a(RE2::Regexp)
     end
 
     it "returns an RE2::Regexp instance given a pattern and options" do
       re = RE2('w(o)(o)', :case_sensitive => false)
-      expect(re).to be_a(RE2::Regexp)
-      expect(re).to_not be_case_sensitive
+
+      expect(re).not_to be_case_sensitive
     end
   end
 end

spec/re2/match_data_spec.rb

@@ -10,6 +10,18 @@
       a = RE2::Regexp.new('(\d?)(a)(b)').match('ab').to_a
       expect(a).to eq(["ab", nil, "a", "b"])
     end
+
+    it "returns UTF-8 strings if the pattern is UTF-8" do
+      a = RE2::Regexp.new('w(o)(o)').match('woo').to_a
+
+      expect(a.map(&:encoding)).to all eq(Encoding::UTF_8)
+    end
+
+    it "returns ISO-8859-1 strings if the pattern is not UTF-8" do
+      a = RE2::Regexp.new('w(o)(o)', :utf8 => false).match('woo').to_a
+
+      expect(a.map(&:encoding)).to all eq(Encoding::ISO_8859_1)
+    end
   end
 
   describe "#[]" do
@@ -19,6 +31,18 @@
       expect(md[2]).to eq("23")
     end
 
+    it "returns a UTF-8 string by numerical index if the pattern is UTF-8" do
+      md = RE2::Regexp.new('(\d)(\d{2})').match("123")
+
+      expect(md[1].encoding).to eq(Encoding::UTF_8)
+    end
+
+    it "returns a ISO-8859-1 string by numerical index if the pattern is not UTF-8" do
+      md = RE2::Regexp.new('(\d)(\d{2})', :utf8 => false).match("123")
+
+      expect(md[1].encoding).to eq(Encoding::ISO_8859_1)
+    end
+
     it "has the whole match as the 0th item" do
       md = RE2::Regexp.new('(\d)(\d{2})').match("123")
       expect(md[0]).to eq("123")

spec/re2/scanner_spec.rb

@@ -21,9 +21,10 @@
   end
 
   describe "#scan" do
-    it "returns the next array of matches" do
+    it "returns the next array of matches", :aggregate_failures do
       r = RE2::Regexp.new('(\w+)')
       scanner = r.scan("It is a truth universally acknowledged")
+
       expect(scanner.scan).to eq(["It"])
       expect(scanner.scan).to eq(["is"])
       expect(scanner.scan).to eq(["a"])
@@ -33,92 +34,123 @@
       expect(scanner.scan).to be_nil
     end
 
+    it "returns multiple capturing groups at a time", :aggregate_failures do
+      r = RE2::Regexp.new('(\w+) (\w+)')
+      scanner = r.scan("It is a truth universally acknowledged")
+
+      expect(scanner.scan).to eq(["It", "is"])
+      expect(scanner.scan).to eq(["a", "truth"])
+      expect(scanner.scan).to eq(["universally", "acknowledged"])
+      expect(scanner.scan).to be_nil
+    end
+
     it "returns an empty array if there are no capturing groups" do
       r = RE2::Regexp.new('\w+')
       scanner = r.scan("Foo bar")
+
       expect(scanner.scan).to eq([])
     end
 
     it "returns nil if there is no match" do
       r = RE2::Regexp.new('\d+')
       scanner = r.scan("Foo bar")
+
       expect(scanner.scan).to be_nil
     end
 
     it "returns nil if the regexp is invalid" do
       r = RE2::Regexp.new('???', :log_errors => false)
       scanner = r.scan("Foo bar")
+
       expect(scanner.scan).to be_nil
     end
 
-    it "returns an empty array if the input is empty" do
+    it "returns an empty array if the input is empty", :aggregate_failures do
       r = RE2::Regexp.new("")
       scanner = r.scan("")
+
       expect(scanner.scan).to eq([])
       expect(scanner.scan).to be_nil
     end
 
-    it "returns an array of nil with an empty input and capture" do
+    it "returns an array of nil with an empty input and capture", :aggregate_failures do
       r = RE2::Regexp.new("()")
       scanner = r.scan("")
+
       expect(scanner.scan).to eq([nil])
       expect(scanner.scan).to be_nil
     end
 
-    it "returns an empty array for every match if the pattern is empty" do
+    it "returns an empty array for every match if the pattern is empty", :aggregate_failures do
       r = RE2::Regexp.new("")
       scanner = r.scan("Foo")
+
       expect(scanner.scan).to eq([])
       expect(scanner.scan).to eq([])
       expect(scanner.scan).to eq([])
       expect(scanner.scan).to eq([])
       expect(scanner.scan).to be_nil
     end
 
-    it "returns an array of nil if the pattern is an empty capturing group" do
+    it "returns an array of nil if the pattern is an empty capturing group", :aggregate_failures do
       r = RE2::Regexp.new("()")
       scanner = r.scan("Foo")
+
       expect(scanner.scan).to eq([nil])
       expect(scanner.scan).to eq([nil])
       expect(scanner.scan).to eq([nil])
       expect(scanner.scan).to eq([nil])
       expect(scanner.scan).to be_nil
     end
 
-    it "returns array of nils with multiple empty capturing groups" do
+    it "returns array of nils with multiple empty capturing groups", :aggregate_failures do
       r = RE2::Regexp.new("()()()")
       scanner = r.scan("Foo")
+
       expect(scanner.scan).to eq([nil, nil, nil])
       expect(scanner.scan).to eq([nil, nil, nil])
       expect(scanner.scan).to eq([nil, nil, nil])
       expect(scanner.scan).to eq([nil, nil, nil])
       expect(scanner.scan).to be_nil
     end
 
-    it "supports empty groups with multibyte characters" do
+    it "supports empty groups with multibyte characters", :aggregate_failures do
       r = RE2::Regexp.new("()€")
       scanner = r.scan("€")
+
       expect(scanner.scan).to eq([nil])
       expect(scanner.scan).to be_nil
     end
+
+    it "raises a type error if given input that can't be coerced to a String" do
+      r = RE2::Regexp.new('(\w+)')
+
+      expect { r.scan(0) }.to raise_error(TypeError)
+    end
+
+    it "accepts input that can be coerced to a String", :aggregate_failures do
+      r = RE2::Regexp.new('(\w+)')
+      scanner = r.scan(StringLike.new("Hello world"))
+
+      expect(scanner.scan).to eq(["Hello"])
+      expect(scanner.scan).to eq(["world"])
+      expect(scanner.scan).to be_nil
+    end
   end
 
   it "is enumerable" do
     r = RE2::Regexp.new('(\d)')
     scanner = r.scan("There are 1 some 2 numbers 3")
+
     expect(scanner).to be_a(Enumerable)
   end
 
   describe "#each" do
     it "yields each match" do
       r = RE2::Regexp.new('(\d)')
       scanner = r.scan("There are 1 some 2 numbers 3")
-      matches = []
-      scanner.each do |match|
-        matches << match
-      end
 
-      expect(matches).to eq([["1"], ["2"], ["3"]])
+      expect { |b| scanner.each(&b) }.to yield_successive_args(["1"], ["2"], ["3"])
     end
 
     it "returns an enumerator when not given a block" do
@@ -135,22 +167,28 @@
   end
 
   describe "#rewind" do
-    it "resets any consumption" do
+    it "resets any consumption", :aggregate_failures do
       r = RE2::Regexp.new('(\d)')
       scanner = r.scan("There are 1 some 2 numbers 3")
+
       expect(scanner.to_enum.first).to eq(["1"])
       expect(scanner.to_enum.first).to eq(["2"])
+
       scanner.rewind
+
       expect(scanner.to_enum.first).to eq(["1"])
     end
 
-    it "resets the eof? check" do
+    it "resets the eof? check", :aggregate_failures do
       r = RE2::Regexp.new('(\d)')
       scanner = r.scan("1")
       scanner.scan
-      expect(scanner.eof?).to be_truthy
+
+      expect(scanner).to be_eof
+
       scanner.rewind
-      expect(scanner.eof?).to be_falsey
+
+      expect(scanner).not_to be_eof
     end
   end
 
@@ -159,46 +197,46 @@
       r = RE2::Regexp.new('(\d)')
       scanner = r.scan("1 2 3")
 
-      expect(scanner.eof?).to be_falsey
+      expect(scanner).not_to be_eof
     end
 
     it "returns true if the input has been consumed" do
       r = RE2::Regexp.new('(\d)')
       scanner = r.scan("1")
       scanner.scan
 
-      expect(scanner.eof?).to be_truthy
+      expect(scanner).to be_eof
     end
 
     it "returns false if no match is made" do
       r = RE2::Regexp.new('(\d)')
       scanner = r.scan("a")
       scanner.scan
 
-      expect(scanner.eof?).to be_falsey
+      expect(scanner).not_to be_eof
     end
 
     it "returns false with an empty input that has not been scanned" do
       r = RE2::Regexp.new("")
       scanner = r.scan("")
 
-      expect(scanner.eof?).to be_falsey
+      expect(scanner).not_to be_eof
     end
 
     it "returns false with an empty input that has not been matched" do
       r = RE2::Regexp.new('(\d)')
       scanner = r.scan("")
       scanner.scan
 
-      expect(scanner.eof?).to be_falsey
+      expect(scanner).not_to be_eof
     end
 
     it "returns true with an empty input that has been matched" do
       r = RE2::Regexp.new("")
       scanner = r.scan("")
       scanner.scan
 
-      expect(scanner.eof?).to be_truthy
+      expect(scanner).to be_eof
     end
   end
 end