Add support for options.run and iife fixtures (#7)

* Add support for options.run and iife fixtures

* Update deps

package.json

@@ -1,6 +1,6 @@
 {
   "name": "chartjs-test-utils",
-  "version": "0.1.2",
+  "version": "0.1.3",
   "description": "Chart.js test utils",
   "main": "dist/chartjs-test-utils.js",
   "module": "dist/chartjs-test-utils.js",
@@ -30,15 +30,15 @@
   },
   "homepage": "https://github.com/chartjs/chartjs-test-utils#readme",
   "devDependencies": {
-    "@rollup/plugin-commonjs": "^17.0.0",
-    "@rollup/plugin-node-resolve": "^11.0.1",
-    "eslint": "^7.16.0",
+    "@rollup/plugin-commonjs": "^17.1.0",
+    "@rollup/plugin-node-resolve": "^11.1.1",
+    "eslint": "^7.19.0",
     "eslint-config-chartjs": "^0.3.0",
     "eslint-plugin-es": "^4.1.0",
-    "rollup": "^2.35.1"
+    "rollup": "^2.38.4"
   },
   "dependencies": {
-    "jasmine": "^3.6.3",
+    "jasmine": "^3.6.4",
     "karma": "^5.2.3",
     "karma-jasmine": "^4.0.1",
     "pixelmatch": "^5.2.1"

src/fixture.js

@@ -21,7 +21,7 @@ function loadConfig(url, callback) {
   readFile(url, function(content) {
     switch (type) {
     case 'js':
-      cfg = new Function('"use strict"; var module = {};' + content + '; return module.exports;')();
+      cfg = new Function('"use strict"; var module = {};' + content + '; return module.exports || fixture;')();
       break;
     case 'json':
       cfg = JSON.parse(content);
@@ -48,16 +48,24 @@ function specFromFixture(description, inputs) {
       }
 
       var chart = _acquireChart(config, json.options);
-      if (!inputs.png) {
-        fail(descr + '\r\nMissing PNG comparison file for ' + input);
-        done();
-      }
+      const _done = () => {
+        if (!inputs.png) {
+          fail(descr + '\r\nMissing PNG comparison file for ' + input);
+          done();
+        }
 
-      readImageData(inputs.png, function(expected) {
-        expect(chart).toEqualImageData(expected, json);
-        _releaseChart(chart);
-        done();
-      });
+        readImageData(inputs.png, function(expected) {
+          expect(chart).toEqualImageData(expected, json);
+          _releaseChart(chart);
+          done();
+        });
+      };
+      const run = json.options && json.options.run;
+      if (typeof run === 'function') {
+        json.options.run(chart, _done);
+      } else {
+        _done();
+      }
     });
   });
 }