Do not attempt to open the browser in tests. (#259)

internal/driver/driver.go

 	}
 
 	if src.HTTPHostport != "" {
-		return serveWebInterface(src.HTTPHostport, p, o)
+		return serveWebInterface(src.HTTPHostport, p, o, true)
 	}
 	return interactive(p, o)
 }

internal/driver/webui.go

 	Top      []report.TextItem
 }
 
-func serveWebInterface(hostport string, p *profile.Profile, o *plugin.Options) error {
+func serveWebInterface(hostport string, p *profile.Profile, o *plugin.Options, wantBrowser bool) error {
 	host, portStr, err := net.SplitHostPort(hostport)
 	if err != nil {
 		return fmt.Errorf("could not split http address: %v", err)
 		},
 	}
 
-	go openBrowser("http://"+args.Hostport, o)
+	if wantBrowser {
+		go openBrowser("http://"+args.Hostport, o)
+	}
 	return server(args)
 }
 

internal/driver/webui_test.go

 		Obj:        fakeObjTool{},
 		UI:         &stdUI{},
 		HTTPServer: creator,
-	})
+	}, false)
 	<-serverCreated
 	defer server.Close()