Add expectKey helper

Similar to expectValue, you can use expectKey to assert that the response
body contains a given a key.

This can be very useful when testing against live APIs where data can
change, but the schema should remain the same.

README.md

@@ -45,6 +45,7 @@ hippie()
 .get('/users/vesln')
 .expectStatus(200)
 .expectHeader('Content-Type', 'application/json; charset=utf-8')
+.expectKey('username')
 .expectValue('username', 'vesln')
 .expectValue('repos[0].name', 'jsmd')
 .expectBody({
@@ -411,6 +412,22 @@ hippie()
 For more information about string paths visit
 [pathval](https://github.com/chaijs/pathval).
 
+### #expectKey
+
+Register a string path expectation for a given key.
+
+```js
+hippie()
+.json()
+.get('https://api.github.com/users/vesln')
+.expectKey('details.company')
+.expectKey('repos[0].name')
+.end(fn);
+```
+
+For more information about string paths visit
+[pathval](https://github.com/chaijs/pathval).
+
 ### #expectBody
 
 Strict expectations:

examples/expectation.js

@@ -10,6 +10,7 @@ api()
 .expectStatus(200)
 .expectHeader('Content-Type', 'application/json; charset=utf-8')
 .expectValue('username', 'vesln')
+.expectKey('repos')
 .expectValue('repos[0].name', 'jsmd')
 .expectBody({
  username: 'vesln',

lib/hippie/client.js

@@ -296,6 +296,19 @@ Client.prototype.expectValue = function(key, val) {
  return this;
 };
 
+/**
+ * Set a key expectation.
+ *
+ * @param {String} string path
+ * @returns {Client} self
+ * @api public
+ */
+
+Client.prototype.expectKey = function(key) {
+ this.expect(expect.keyCheck(key));
+ return this;
+};
+
 /**
  * Set a body expectation.
  *

lib/hippie/expect.js

@@ -55,6 +55,22 @@ exports.value = function(key, val) {
  };
 };
 
+/**
+ * Return a key expectation.
+ *
+ * @param {String} string path
+ * @returns {Function}
+ * @api public
+ */
+
+exports.keyCheck = function(keyParam) {
+ return function keyCheck(res, body, next) {
+ var value = pathval(keyParam, body);
+ var notUndefined = typeof value !== 'undefined';
+ next(assert(notUndefined, true, 'Key - ' + keyParam));
+ };
+};
+
 /**
  * Return a body expectation.
  *

test/expect-key.test.js

@@ -0,0 +1,31 @@
+
+describe('#expectKey', function() {
+ it('returns an error when the key is missing from the response', function(done) {
+ api()
+ .json()
+ .get('/keys')
+ .expectKey('non_existing')
+ .end(function(err) {
+ err.should.be.ok;
+ done();
+ });
+ });
+
+ it('does not return an error when the key is present', function(done) {
+ api()
+ .json()
+ .get('/keys')
+ .expectKey('hippie')
+ .end(done);
+ });
+
+ it('should work with falsy values if key is present', function(done) {
+ api()
+ .json()
+ .get('/keys')
+ .expectKey('blank')
+ .expectKey('nullable')
+ .expectKey('boolean')
+ .end(done);
+ });
+});

test/support/server.js

@@ -48,6 +48,10 @@ app.get('/list', function(req, res) {
  res.json([{ id: 4 }]);
 });
 
+app.get('/keys', function(req, res) {
+ res.json({ hippie: 'cool', blank: '', nullable: null, boolean: false });
+});
+
 app.get('/user', function(req, res) {
  res.json({ id: 4 });
 });