maven找不到slf4j rollingfileappender

我遇到一个问题,maven在运行JUnit测试时没有找到slf4j类:

22:20:05,412 |-INFO in ch.qos.logback.classic.LoggerContext[default] - Could NOT find resource [logback.groovy]
22:20:05,412 |-INFO in ch.qos.logback.classic.LoggerContext[default] - Found resource [logback-test.xml] at [file:/home/ram/src/2dd/java/dd2/target/test-classes/logback-test.xml]
22:20:05,526 |-INFO in ch.qos.logback.core.joran.action.AppenderAction - About to instantiate appender of type [ch.qos.logback.core.RollingFileAppender]
22:20:05,527 |-ERROR in ch.qos.logback.core.joran.action.AppenderAction - Could not create an Appender of type [ch.qos.logback.core.RollingFileAppender]. ch.qos.logback.core.util.DynamicClassLoadingException: Failed to instantiate type ch.qos.logback.core.RollingFileAppender

但是,slf4j jar文件正被添加到类路径中:

[DEBUG] test classpath classpath:
[DEBUG]   /home/ram/src/2dd/java/dd2/target/test-classes
[DEBUG]   /home/ram/src/2dd/java/dd2/target/classes
[DEBUG]   /home/ram/.m2/repository/junit/junit/4.11/junit-4.11.jar
[DEBUG]   /home/ram/.m2/repository/org/hamcrest/hamcrest-core/1.3/hamcrest-core-1.3.jar
[DEBUG]   /home/ram/.m2/repository/com/fallabs/kyotocabinet-java/1.24/kyotocabinet-java-1.24.jar
[DEBUG]   /home/ram/.m2/repository/ch/qos/logback/logback-classic/1.0.13/logback-classic-1.0.13.jar
[DEBUG]   /home/ram/.m2/repository/ch/qos/logback/logback-core/1.0.13/logback-core-1.0.13.jar
[DEBUG]   /home/ram/.m2/repository/org/slf4j/slf4j-api/1.7.5/slf4j-api-1.7.5.jar
[DEBUG] provider classpath classpath:
[DEBUG]   /home/ram/.m2/repository/org/apache/maven/surefire/surefire-junit4/2.12.4/surefire-junit4-2.12.4.jar
[DEBUG]   /home/ram/.m2/repository/org/apache/maven/surefire/surefire-api/2.12.4/surefire-api-2.12.4.jar

我的logback-test.xml文件紧跟以下示例:http://logback.qos.ch/manual/appenders.html

  
  gen-test.log
  
    gen-test.%i.log
    1
    3
  

  
    2MB
  

  
    %date %level [%thread] %logger{36} [%file:%line] - %msg%n
   
   


  
    
  

我的pom.xml包含以下相关部分:

  junit
  junit
  4.11
  test

  
  ch.qos.logback
  logback-classic
  1.0.13

....
  
    org.apache.maven.plugins
    maven-compiler-plugin
    3.1
    
      true
      true
      
      1.7
      1.7
      1.7
      
        
        -Xlint
      
    
  


  org.apache.maven.plugins
  maven-surefire-plugin
  2.16
  
    0
    
    -Xms128m -Xmx1g
    -Djava.library.path=.:/usr/local/lib
    false 
    false 
    
  

感谢任何帮助,谢谢.