support returning promises from dynamic fixtures

core.js

@@ -213,9 +213,19 @@ exports.callDynamicFixture = function(xhrSettings, fixtureSettings, cb){
 		// fall the fixture
 		var result = fixtureSettings.fixture(xhrSettings, response, xhrSettings.headers, fixtureSettings);
 
-		if (result !== undefined) {
-			// Resolve with fixture results
-			response(200, result );
+		if (canReflect.isPromise(result)) {
+			// If we have a promise, wait for it to resolve
+			result.then(function (result) {
+				if (result !== undefined) {
+					// Resolve with fixture results
+					response(200, result );
+				}
+			});
+		} else {
+			if (result !== undefined) {
+				// Resolve with fixture results
+				response(200, result );
+			}
 		}
 	};
 

docs/can-fixture.md

@@ -11,6 +11,8 @@
 
   If an XHR request matches ajaxSettings, calls requestHandler with the XHR requests data. Makes the XHR request respond with the return value of requestHandler or the result of calling its response argument.
 
+  When adding a fixture, it will remove any identical fixtures from the list of fixtures. The last fixture added will be the first matched.
+
   The following traps requests to GET /todos and responds with an array of data:
 
   ```js
@@ -34,7 +36,44 @@
   ```
   @codepen
 
-  When adding a fixture, it will remove any identical fixtures from the list of fixtures. The last fixture added will be the first matched.
+  Return a [Promise](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise) (or use [async](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/async_function) & [await](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/await)) from `requestHandler` to asynchronously return results. This allows fixtures to depend on each other, introduce dynamic delays, and even depend on external resources.
+
+  ```js
+  import {fixture, ajax} from "can";
+
+  fixture( { method: "get", url: "/todos" },
+    ( request, response, headers, ajaxSettings ) => {
+      return new Promise((resolve) => {
+        setTimeout(() => resolve({
+          data: [
+            { id: 1, name: "dishes" },
+            { id: 2, name: "mow" }
+          ]
+        }), 1000);
+	  });
+    }
+  );
+
+  // or
+
+  fixture( { method: "get", url: "/todos" },
+    async ( request, response, headers, ajaxSettings ) => {
+      await delay(1000);
+      return {
+        data: [
+          { id: 1, name: "dishes" },
+          { id: 2, name: "mow" }
+        ]
+      };
+    });
+  );
+
+  ajax( {url: "/todos"} ).then( result => {
+    console.log( result.data ); //-> [{id: 1, name: "dishes"}, {id:2, name: "mow"}]
+  } );
+
+  ```
+  @codepen
 
   @param {can-fixture/types/ajaxSettings} ajaxSettings An object that is used to match values on an XHR object, namely the url and method. url can be templated like `/todos/{_id}`.
   @param {can-fixture.requestHandler} requestHandler Handles the request and provides a response.
@@ -67,7 +106,7 @@
   @codepen
   @highlight 3
 
-  @param {can-fixture/types/ajaxSettings} ajaxSettings An object that is used to match values on an XHR object, namely the url and method. url can be templated like `/tasks/{_id}`. 
+  @param {can-fixture/types/ajaxSettings} ajaxSettings An object that is used to match values on an XHR object, namely the url and method. url can be templated like `/tasks/{_id}`.
   @param {String} url The pathname of requests that will be trapped.
 
 @signature `fixture( ajaxSettings, data )`
@@ -182,7 +221,7 @@
     "GET /tasks": { data: [ {id: 1, name: "mow lawn"} ] },
     "/people": "fixtures/people.json"
   } );
-  
+
   ajax( {type: "POST", url:"/tasks"} ).then( result => {
     console.log( result ); //-> {id: RandomNumber}
   } );
@@ -249,6 +288,6 @@
 @signature `fixture(ajaxSettingsArray)`
 
   Add fixtures that have been previously removed with another call to fixture.
-  
+
   @param {Array<can-fixture/types/ajaxSettings>}  An array of AJAX settings objects
-  @return {Array<can-fixture/types/ajaxSettings>} Returns an array of any fixtures that are replaced by the fixtures that are added.
+  @return {Array<can-fixture/types/ajaxSettings>} Returns an array of any fixtures that are replaced by the fixtures that are added.

test/fixture_test.js

@@ -135,11 +135,27 @@ test('dynamic fixtures', function () {
 		.done(function (data) {
 			equal(data[0].sweet, 'ness', 'can.get works');
 			start();
-		}).catch(function(err){
-			debugger;
 		});
 });
 
+test('dynamic fixtures return promises', function () {
+	stop();
+	fixture.delay = 10;
+	fixture('something', function () {
+		return Promise.resolve([{
+			sweet: 'ness'
+		}]);
+	});
+
+	$.ajax({
+		url: 'something',
+		dataType: 'json'
+	}).then(function (data) {
+		equal(data[0].sweet, 'ness', 'can.get works');
+		start();
+	});
+});
+
 if (__dirname !== '/') {
 	test('fixture function', 3, function () {
 		stop();
@@ -1832,7 +1848,7 @@ test('fixture returns the old fixture callback when fixtures are removed (#34)',
 		return "foo";
 	};
 	fixture("/services/thing", funcA);
-  
+
 	// in a test, remove default fixture and provide your own
 	var oldFixtures = fixture("/services/thing", null);
 	QUnit.deepEqual(oldFixtures, [{fixture: funcA, url: '/services/thing'}]);