old_contents: "use strict";
  
  var testHelper = require("../test-helper");
  
  testHelper.assertionTests("assert", "isString", function(
      pass,
      fail,
      msg,
      error
  ) {
      pass("for string", "Hey");
      fail("for object", {});
      msg(
          "fail with descriptive message",
          "[assert.isString] Expected {  } (object) to be string",
          {}
      );
      msg(
          "fail with custom message",
          "[assert.isString] Snap: Expected {  } (object) to be string",
          {},
          "Snap"
      );
      error(
          "for object",
          {
              code: "ERR_ASSERTION",
              actual: "object",
              expected: "string",
              operator: "assert.isString"
          },
          {}
      );
  });
  
  testHelper.assertionTests("refute", "isString", function(
      pass,
      fail,
      msg,
      error
  ) {
      fail("for string", "Hey");
      pass("for object", {});
      msg(
          "fail with descriptive message",
          "[refute.isString] Expected Yo not to be string",
          "Yo"
      );
      msg(
          "fail with custom message",
          "[refute.isString] Here goes: Expected Yo not to be string",
          "Yo",
          "Here goes"
      );
      error(
          "for string",
          {
              code: "ERR_ASSERTION",
              operator: "refute.isString"
          },
          "Hey"
      );
  });
  
new_contents: "use strict";
  
  var assert = require("assert");
  var referee = require("../referee");
  
  describe("isString", function() {
      it("should pass for string", function() {
          referee.assert.isString("Hey");
      });
  
      it("should fail for object", function() {
          var actual;
          try {
              referee.assert.isString({});
          } catch (err) {
              actual = err;
          }
          assert.equal(actual.code, "ERR_ASSERTION");
          assert.equal(actual.operator, "assert.isString");
      });
  
      it("should fail for array", function() {
          var actual;
          try {
              referee.assert.isString([]);
          } catch (err) {
              actual = err;
          }
          assert.equal(actual.code, "ERR_ASSERTION");
          assert.equal(actual.operator, "assert.isString");
      });
  
      it("should fail for number", function() {
          var actual;
          try {
              referee.assert.isString(34);
          } catch (err) {
              actual = err;
          }
          assert.equal(actual.code, "ERR_ASSERTION");
          assert.equal(actual.operator, "assert.isString");
      });
  
      it("should fail for boolean", function() {
          var actual;
          try {
              referee.assert.isString(true);
          } catch (err) {
              actual = err;
          }
          assert.equal(actual.code, "ERR_ASSERTION");
          assert.equal(actual.operator, "assert.isString");
      });
  });
  
subject: remove test helper from isString function