225 lines
7.3 KiB
JavaScript
225 lines
7.3 KiB
JavaScript
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'use strict';
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var hasSymbols = require('has-symbols/shams')();
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var forEach = require('for-each');
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module.exports = function (assign, t) {
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t.test('error cases', function (st) {
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st['throws'](function () { assign(null); }, TypeError, 'target must be an object');
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st['throws'](function () { assign(undefined); }, TypeError, 'target must be an object');
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st['throws'](function () { assign(null, {}); }, TypeError, 'target must be an object');
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st['throws'](function () { assign(undefined, {}); }, TypeError, 'target must be an object');
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st.end();
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});
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t.test('non-object target, no sources', function (st) {
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var bool = assign(true);
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st.equal(typeof bool, 'object', 'bool is object');
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st.equal(Boolean.prototype.valueOf.call(bool), true, 'bool coerces to `true`');
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var number = assign(1);
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st.equal(typeof number, 'object', 'number is object');
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st.equal(Number.prototype.valueOf.call(number), 1, 'number coerces to `1`');
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var string = assign('1');
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st.equal(typeof string, 'object', 'number is object');
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st.equal(String.prototype.valueOf.call(string), '1', 'number coerces to `"1"`');
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st.end();
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});
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t.test('non-object target, with sources', function (st) {
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var signal = {};
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st.test('boolean', function (st2) {
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var bool = assign(true, { a: signal });
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st2.equal(typeof bool, 'object', 'bool is object');
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st.equal(Boolean.prototype.valueOf.call(bool), true, 'bool coerces to `true`');
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st2.equal(bool.a, signal, 'source properties copied');
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st2.end();
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});
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st.test('number', function (st2) {
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var number = assign(1, { a: signal });
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st2.equal(typeof number, 'object', 'number is object');
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st2.equal(Number.prototype.valueOf.call(number), 1, 'number coerces to `1`');
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st2.equal(number.a, signal, 'source properties copied');
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st2.end();
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});
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st.test('string', function (st2) {
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var string = assign('1', { a: signal });
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st2.equal(typeof string, 'object', 'number is object');
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st2.equal(String.prototype.valueOf.call(string), '1', 'number coerces to `"1"`');
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st2.equal(string.a, signal, 'source properties copied');
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st2.end();
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});
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st.end();
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});
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t.test('non-object sources', function (st) {
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st.deepEqual(assign({ a: 1 }, null, { b: 2 }), { a: 1, b: 2 }, 'ignores null source');
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st.deepEqual(assign({ a: 1 }, { b: 2 }, undefined), { a: 1, b: 2 }, 'ignores undefined source');
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st.end();
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});
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t.test('returns the modified target object', function (st) {
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var target = {};
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var returned = assign(target, { a: 1 });
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st.equal(returned, target, 'returned object is the same reference as the target object');
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st.end();
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});
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t.test('has the right length', function (st) {
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st.equal(assign.length, 2, 'length is 2 => 2 required arguments');
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st.end();
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});
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t.test('merge two objects', function (st) {
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var target = { a: 1 };
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var returned = assign(target, { b: 2 });
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st.deepEqual(returned, { a: 1, b: 2 }, 'returned object has properties from both');
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st.end();
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});
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t.test('works with functions', function (st) {
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var target = function () {};
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target.a = 1;
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var returned = assign(target, { b: 2 });
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st.equal(target, returned, 'returned object is target');
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st.equal(returned.a, 1);
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st.equal(returned.b, 2);
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st.end();
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});
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t.test('works with primitives', function (st) {
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var target = 2;
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var source = { b: 42 };
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var returned = assign(target, source);
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st.equal(Object.prototype.toString.call(returned), '[object Number]', 'returned is object form of number primitive');
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st.equal(Number(returned), target, 'returned and target have same valueOf');
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st.equal(returned.b, source.b);
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st.end();
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});
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t.test('merge N objects', function (st) {
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var target = { a: 1 };
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var source1 = { b: 2 };
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var source2 = { c: 3 };
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var returned = assign(target, source1, source2);
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st.deepEqual(returned, { a: 1, b: 2, c: 3 }, 'returned object has properties from all sources');
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st.end();
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});
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t.test('only iterates over own keys', function (st) {
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var Foo = function () {};
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Foo.prototype.bar = true;
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var foo = new Foo();
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foo.baz = true;
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var target = { a: 1 };
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var returned = assign(target, foo);
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st.equal(returned, target, 'returned object is the same reference as the target object');
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st.deepEqual(target, { a: 1, baz: true }, 'returned object has only own properties from both');
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st.end();
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});
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t.test('includes enumerable symbols, after keys', { skip: !hasSymbols }, function (st) {
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var visited = [];
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var obj = {};
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Object.defineProperty(obj, 'a', { enumerable: true, get: function () { visited.push('a'); return 42; } });
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var symbol = Symbol('enumerable');
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Object.defineProperty(obj, symbol, {
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enumerable: true,
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get: function () { visited.push(symbol); return Infinity; }
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});
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var nonEnumSymbol = Symbol('non-enumerable');
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Object.defineProperty(obj, nonEnumSymbol, {
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enumerable: false,
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get: function () { visited.push(nonEnumSymbol); return -Infinity; }
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});
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var target = assign({}, obj);
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st.deepEqual(visited, ['a', symbol], 'key is visited first, then symbol');
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st.equal(target.a, 42, 'target.a is 42');
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st.equal(target[symbol], Infinity, 'target[symbol] is Infinity');
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st.notEqual(target[nonEnumSymbol], -Infinity, 'target[nonEnumSymbol] is not -Infinity');
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st.end();
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});
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t.test('does not fail when symbols are not present', function (st) {
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var getSyms;
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if (hasSymbols) {
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getSyms = Object.getOwnPropertySymbols;
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delete Object.getOwnPropertySymbols;
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}
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var visited = [];
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var obj = {};
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Object.defineProperty(obj, 'a', { enumerable: true, get: function () { visited.push('a'); return 42; } });
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var keys = ['a'];
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if (hasSymbols) {
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var symbol = Symbol('sym');
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Object.defineProperty(obj, symbol, {
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enumerable: true,
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get: function () { visited.push(symbol); return Infinity; }
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});
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keys.push(symbol);
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}
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var target = assign({}, obj);
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st.deepEqual(visited, keys, 'assign visits expected keys');
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st.equal(target.a, 42, 'target.a is 42');
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if (hasSymbols) {
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st.equal(target[symbol], Infinity);
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Object.getOwnPropertySymbols = getSyms;
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}
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st.end();
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});
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t.test('preserves correct property enumeration order', function (st) {
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var str = 'abcdefghijklmnopqrst';
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var letters = {};
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forEach(str.split(''), function (letter) {
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letters[letter] = letter;
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});
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var n = 5;
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st.comment('run the next test ' + n + ' times');
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var object = assign({}, letters);
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var actual = '';
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for (var k in object) {
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actual += k;
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}
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for (var i = 0; i < n; ++i) {
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st.equal(actual, str, 'property enumeration order should be followed');
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}
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st.end();
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});
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t.test('checks enumerability and existence, in case of modification during [[Get]]', { skip: !Object.defineProperty }, function (st) {
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var targetBvalue = {};
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var targetCvalue = {};
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var target = { b: targetBvalue, c: targetCvalue };
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var source = {};
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Object.defineProperty(source, 'a', {
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enumerable: true,
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get: function () {
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delete this.b;
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Object.defineProperty(this, 'c', { enumerable: false });
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return 'a';
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}
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});
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var sourceBvalue = {};
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var sourceCvalue = {};
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source.b = sourceBvalue;
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source.c = sourceCvalue;
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var result = assign(target, source);
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st.equal(result, target, 'sanity check: result is === target');
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st.equal(result.b, targetBvalue, 'target key not overwritten by deleted source key');
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st.equal(result.c, targetCvalue, 'target key not overwritten by non-enumerable source key');
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st.end();
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});
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};
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