Fix tests on OSX with retina screen

* Fix retina unit test failures
* Honor config file formatting
* Prevent gulp error on non-zero karma result

.editorconfig

@@ -8,3 +8,11 @@ end_of_line = lf
 charset = utf-8
 trim_trailing_whitespace = true
 insert_final_newline = false
+
+[gulpfile.js]
+indent_style = space
+indent_size = 2
+
+[*.yml]
+indent_style = space
+indent_size = 2

gulpfile.js

@@ -188,7 +188,12 @@ function unittestTask(done) {
     args: {
       coverage: !!argv.coverage
     }
-  }, done).start();
+  },
+  // https://github.com/karma-runner/gulp-karma/issues/18
+  function(error) {
+    error = error ? new Error('Karma returned with the error code: ' + error) : undefined;
+    done(error);
+  }).start();
 }
 
 function librarySizeTask() {

test/jasmine.index.js

@@ -22,6 +22,10 @@ var utils = require('./jasmine.utils');
 		return new Context();
 	}
 
+	// force ratio=1 for tests on high-res/retina devices
+	// fixes https://github.com/chartjs/Chart.js/issues/4515
+	window.devicePixelRatio = 1;
+
 	window.acquireChart = acquireChart;
 	window.releaseChart = releaseChart;
 	window.waitForResize = utils.waitForResize;

test/specs/platform.dom.tests.js

@@ -394,8 +394,8 @@ describe('Platform.dom', function() {
 			expect(notifiedEvent.type).toBe(evt.type);
 
 			// Relative Position
-			expect(notifiedEvent.x).toBe(chart.width / 2);
-			expect(notifiedEvent.y).toBe(chart.height / 2);
+			expect(notifiedEvent.x).toBeCloseToPixel(chart.width / 2);
+			expect(notifiedEvent.y).toBeCloseToPixel(chart.height / 2);
 		});
 	});
 });