org.openqa.selenium.WebDriverException: Cannot find firefox binary in PATH. Make sure firefox is installed. OS appears to be: VISTA
Build info: version: '2.48.2', revision: '41bccdd', time: '2015-10-09 19:59:12'
System info: host: 'MININT-RQ9DS4O', ip: '30.10.3.30', os.name: 'Windows 7', os.arch: 'amd64', os.version: '6.1', java.version: '1.7.0_60'
Driver info: driver.version: FirefoxDriver

解决办法有四个：

1.重新安装firefox在默认路径下；

OS

Expected Location of Firefox

Linux

firefox (found using "which")

Mac

/Applications/Firefox.app/Contents/MacOS/firefox

Windows

%PROGRAMFILES%\Mozilla Firefox\firefox.exe

2.直接用System.setProperty方法设置webdriver.firefox.bin的值 ；

3.利用setCapability进行设置 ；

4.用FirefoxBinary类和public FirefoxDriver(FirefoxBinary binary, FirefoxProfile profile)这个构造方法；

参考：http://sariyalee.iteye.com/blog/1688271