             }
             
             func onTestSuccess(inputField: NSTextField, outputField: NSTextField, label: NSTextField) {
+                let endTime = NSDate();
+                let timeInterval: Double = endTime.timeIntervalSinceDate(startTime);
+                
                 inputField.textColor = .blackColor()
                 outputField.textColor = .blackColor()
-                label.stringValue = ""
+                // formatting from realityone's answer to http://stackoverflow.com/questions/24051314/precision-string-format-specifier-in-swift
+                label.stringValue = String(format: "Success (%.2f s)",  timeInterval)
             }
             
             func onTestSyntaxError(inputField: NSTextField, outputField: NSTextField, spinner: NSProgressIndicator, label: NSTextField) {

    func runSchemeCode() {
        
        startSpinner()
    
        // Path to Chez Scheme
        // Perhaps this should be settable in a preferences panel.

            print("error datastring for process \( self.task.processIdentifier ): \(errorDatastring)")
        }
    }
}
