1 files changed, 140 insertions, 0 deletions
diff --git a/test/fetch/iterators.js b/test/fetch/iterators.js
new file mode 100644
index 0000000..6c6761d
--- /dev/null
+++ b/test/fetch/iterators.js
@@ -0,0 +1,140 @@
+'use strict'
+
+const { test } = require('tap')
+const { Headers, FormData } = require('../..')
+
+test('Implements " Iterator" properly', (t) => {
+  t.test('all Headers iterators implement Headers Iterator', (t) => {
+    const headers = new Headers([['a', 'b'], ['c', 'd']])
+
+    for (const iterable of ['keys', 'values', 'entries', Symbol.iterator]) {
+      const gen = headers[iterable]()
+      // https://tc39.es/ecma262/#sec-%25iteratorprototype%25-object
+      const IteratorPrototype = Object.getPrototypeOf(Object.getPrototypeOf([][Symbol.iterator]()))
+      const iteratorProto = Object.getPrototypeOf(gen)
+
+      t.ok(gen.constructor === Object)
+      t.ok(gen.prototype === undefined)
+      // eslint-disable-next-line no-proto
+      t.equal(gen.__proto__[Symbol.toStringTag], 'Headers Iterator')
+      // https://github.com/node-fetch/node-fetch/issues/1119#issuecomment-100222049
+      t.notOk(Headers.prototype[iterable] instanceof function * () {}.constructor)
+      // eslint-disable-next-line no-proto
+      t.ok(gen.__proto__.next.__proto__ === Function.prototype)
+      // https://webidl.spec.whatwg.org/#dfn-iterator-prototype-object
+      // "The [[Prototype]] internal slot of an iterator prototype object must be %IteratorPrototype%."
+      t.equal(gen[Symbol.iterator], IteratorPrototype[Symbol.iterator])
+      t.equal(Object.getPrototypeOf(iteratorProto), IteratorPrototype)
+    }
+
+    t.end()
+  })
+
+  t.test('all FormData iterators implement FormData Iterator', (t) => {
+    const fd = new FormData()
+
+    for (const iterable of ['keys', 'values', 'entries', Symbol.iterator]) {
+      const gen = fd[iterable]()
+      // https://tc39.es/ecma262/#sec-%25iteratorprototype%25-object
+      const IteratorPrototype = Object.getPrototypeOf(Object.getPrototypeOf([][Symbol.iterator]()))
+      const iteratorProto = Object.getPrototypeOf(gen)
+
+      t.ok(gen.constructor === Object)
+      t.ok(gen.prototype === undefined)
+      // eslint-disable-next-line no-proto
+      t.equal(gen.__proto__[Symbol.toStringTag], 'FormData Iterator')
+      // https://github.com/node-fetch/node-fetch/issues/1119#issuecomment-100222049
+      t.notOk(Headers.prototype[iterable] instanceof function * () {}.constructor)
+      // eslint-disable-next-line no-proto
+      t.ok(gen.__proto__.next.__proto__ === Function.prototype)
+      // https://webidl.spec.whatwg.org/#dfn-iterator-prototype-object
+      // "The [[Prototype]] internal slot of an iterator prototype object must be %IteratorPrototype%."
+      t.equal(gen[Symbol.iterator], IteratorPrototype[Symbol.iterator])
+      t.equal(Object.getPrototypeOf(iteratorProto), IteratorPrototype)
+    }
+
+    t.end()
+  })
+
+  t.test('Iterator symbols are properly set', (t) => {
+    t.test('Headers', (t) => {
+      const headers = new Headers([['a', 'b'], ['c', 'd']])
+      const gen = headers.entries()
+
+      t.equal(typeof gen[Symbol.toStringTag], 'string')
+      t.equal(typeof gen[Symbol.iterator], 'function')
+      t.end()
+    })
+
+    t.test('FormData', (t) => {
+      const fd = new FormData()
+      const gen = fd.entries()
+
+      t.equal(typeof gen[Symbol.toStringTag], 'string')
+      t.equal(typeof gen[Symbol.iterator], 'function')
+      t.end()
+    })
+
+    t.end()
+  })
+
+  t.test('Iterator does not inherit Generator prototype methods', (t) => {
+    t.test('Headers', (t) => {
+      const headers = new Headers([['a', 'b'], ['c', 'd']])
+      const gen = headers.entries()
+
+      t.equal(gen.return, undefined)
+      t.equal(gen.throw, undefined)
+      t.equal(typeof gen.next, 'function')
+
+      t.end()
+    })
+
+    t.test('FormData', (t) => {
+      const fd = new FormData()
+      const gen = fd.entries()
+
+      t.equal(gen.return, undefined)
+      t.equal(gen.throw, undefined)
+      t.equal(typeof gen.next, 'function')
+
+      t.end()
+    })
+
+    t.end()
+  })
+
+  t.test('Symbol.iterator', (t) => {
+    // Headers
+    const headerValues = new Headers([['a', 'b']]).entries()[Symbol.iterator]()
+    t.same(Array.from(headerValues), [['a', 'b']])
+
+    // FormData
+    const formdata = new FormData()
+    formdata.set('a', 'b')
+    const formdataValues = formdata.entries()[Symbol.iterator]()
+    t.same(Array.from(formdataValues), [['a', 'b']])
+
+    t.end()
+  })
+
+  t.test('brand check', (t) => {
+    // Headers
+    t.throws(() => {
+      const gen = new Headers().entries()
+      // eslint-disable-next-line no-proto
+      gen.__proto__.next()
+    }, TypeError)
+
+    // FormData
+    t.throws(() => {
+      const gen = new FormData().entries()
+      // eslint-disable-next-line no-proto
+      gen.__proto__.next()
+    }, TypeError)
+
+    t.end()
+  })
+
+  t.end()
+})