tests.js

var stringReplaceString = require('./string-replace-stream');
var expect = require('expect.js');
var concat = require('concat-stream');


describe('string-replace-stream', function () {
  // First test KNP table building internal function
  describe('_buildTable', function () {
    it('should build knp table', function () {
      expect(stringReplaceString._buildTable("ABCDABD")).eql([-1, 0, 0, 0, 0, 1, 2]);
      expect(stringReplaceString._buildTable("PARTICIPATE IN PARACHUTE")).eql([
          -1,0,0,0,0,0,0,0,1,2,0,0,0,0,0,0,1,2,3,0,0,0,0,0
      ]);
    });
  });

  // Ruining poetry with node.js
  ["string", "buffer"].forEach(function (type) {
    function testReplacement(haystack, search, replace, result, done) {
      replaceStream = stringReplaceString(search, replace);
      replaceStream.pipe(concat({encoding: 'string'}, complete));
      haystack.forEach(function (h) {
        if (type === "buffer") {
          replaceStream.write(new Buffer(h, 'utf8'));
        } else {
          replaceStream.write(h);
        }
      });
      replaceStream.end();

      function complete(output) {
        expect(output).to.equal(result);
        done();
      }
    }

    describe('with input ' + type, function () {
      it('should replace one instance of the search string with the replacement string inside a chunk', function (done) {
        testReplacement(
          ["'Twas brillig, and the slithy toves"],
          "slithy",
          "slimy",
          "'Twas brillig, and the slimy toves",
          done
        );
      });

      it('should replace search string with replacement string spanning 2 chunks', function (done) {
        testReplacement(
          ["'Twas brillig, and the slithy toves\n", "Did gyre and gimble in the wabe;"],
          "toves\nDid gyre",
          "badgers\nDid rotate",
          "'Twas brillig, and the slithy badgers\nDid rotate and gimble in the wabe;",
          done
        );
      });

      it('should replace search string with replacement string spanning 3 chunks', function (done) {
        testReplacement(
          ["'Twas brillig, and the slithy toves\n", "Did gyre and gimble in the wabe;\n", "All mimsy were the borogoves,"],
          "toves\nDid gyre and gimble in the wabe;\nAll mimsy",
          "badgers\nDid rotate and bore in the side of the hill;\nAll flimsy and miserable",
          "'Twas brillig, and the slithy badgers\nDid rotate and bore in the side of the hill;\nAll flimsy and miserable were the borogoves,",
          done
        );
      });

      it('should replace multiple occurrences of search string with replacment string', function (done) {
        testReplacement(
          ["'Twas brillig, and the slithy toves\n", "Did gyre and gimble in the wabe;\n", "All mimsy were the borogoves,"],
          "the",
          "that",
          "'Twas brillig, and that slithy toves\nDid gyre and gimble in that wabe;\nAll mimsy were that borogoves,",
          done
        );
      });

      it('should replace multiple occurances of search string next to each other with replacement string', function (done) {
        testReplacement(
          ["testtestte","sttesttesttes","tHELLOtest"],
          "test",
          "badger",
          "badgerbadgerbadgerbadgerbadgerbadgerHELLObadger",
          done
        );
      });

      it('should replace the whole lot if it matches', function (done) {
        testReplacement(
          ["'Twas brillig, and the slithy toves\n", "Did gyre and gimble in the wabe;\n", "All mimsy were the borogoves,"],
          "'Twas brillig, and the slithy toves\nDid gyre and gimble in the wabe;\nAll mimsy were the borogoves,",
          "It was four in the afternoon, and the slimy badgers were rotating and boring into the hill. Some birds were miserable and a bit flimsy",
          "It was four in the afternoon, and the slimy badgers were rotating and boring into the hill. Some birds were miserable and a bit flimsy",
          done
        );
      });


      it('should handle a prefix of the search string overlapping the actual search', function (done) {
        testReplacement(
          ["abcabcabcabcdtesttest"],
          "abcabcd",
          "badger",
          "abcabcbadgertesttest",
          done
        );
      });

      it('should handle match no matter where it falls on chunk break', function (done) {
        var haystack = "the Jabberwock son!";
        var todo = 0;
        function doneOne() {
          todo--;
          if (todo === 0) done();
        }
        for (var i = 1; i < haystack.length-1; i++) {
          for (var k = i + 1; k < haystack.length-1; k++) {
            todo++;
            testReplacement(
              [haystack.slice(0, i), haystack.slice(i, k), haystack.slice(k) + k],
              "Jabber",
              "XMPP",
              "the XMPPwock son!" + k,
              doneOne
            );
          }
        }
      });


      it('should handle a prefix of the search string overlapping the actual search broken into chunks', function (done) {
        testReplacement(
          ["abcabcabc","abcdtest","test"],
          "abcabcd",
          "badger",
          "abcabcbadgertesttest",
          done
        );
      });

      it('should handle "dangling tails" where the stream ends in a prefix of the search string', function (done) {
        testReplacement(
          ["abcefg","hijklmnopqrstu","vw"],
          "uvwxyz",
          "test",
          "abcefghijklmnopqrstuvw",
          done
        );
      });

    });
  });


  it('should handle unicode characters split between blocks', function (done) {
    var input = new Buffer("My ☃ cost £100 🙁!", "utf-8");
    var replaceStream = stringReplaceString("☃ cost £100 🙁", "snowman cost £100 :(");
    replaceStream.pipe(concat({encoding: 'string'}, complete));

    // One byte at a time, doesn't get any more split than that
    for (var i = 0; i < input.length; i++) {
      replaceStream.write(input.slice(i,i+1));
    }
    replaceStream.end();

    function complete(output) {
      expect(output).to.equal(("My snowman cost £100 :(!"));
      done();
    }
  });
});