单元测试时Junit报错，求解

org.mybatis.spring.MyBatisSystemException: nested exception is org.apache.ibatis.exceptions.PersistenceException:
### Error querying database.  Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Could not get JDBC Connection; nested exception is java.sql.SQLException: An attempt by a client to checkout a Connection has timed out.
### The error may exist in file [D:\apache-maven-3.3.9Project\Projects\seckill\target\classes\mappers\seckillDAO.xml]
### The error may involve cn.jr.dao.SeckillDAO.queryById
### The error occurred while executing a query
### Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Could not get JDBC Connection; nested exception is java.sql.SQLException: An attempt by a client to checkout a Connection has timed out.
 at org.mybatis.spring.MyBatisExceptionTranslator.translateExceptionIfPossible(MyBatisExceptionTranslator.java:77)
 at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:446)
 at com.sun.proxy.$Proxy16.selectOne(Unknown Source)
 at org.mybatis.spring.SqlSessionTemplate.selectOne(SqlSessionTemplate.java:166)
 at org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:82)
 at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:53)
 at com.sun.proxy.$Proxy17.queryById(Unknown Source)
 at cn.jr.dao.SeckillDAOTest.testQueryById(SeckillDAOTest.java:34)
 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
 at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
 at java.lang.reflect.Method.invoke(Method.java:498)
 at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
 at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
 at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
 at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
 at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:75)
 at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:86)
 at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:84)
 at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
 at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:252)
 at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:94)
 at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
 at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
 at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
 at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
 at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
 at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
 at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
 at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
 at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:191)
 at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)
 at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459)
 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:678)
 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)
Caused by: org.apache.ibatis.exceptions.PersistenceException:
### Error querying database.  Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Could not get JDBC Connection; nested exception is java.sql.SQLException: An attempt by a client to checkout a Connection has timed out.
### The error may exist in file [D:\apache-maven-3.3.9Project\Projects\seckill\target\classes\mappers\seckillDAO.xml]
### The error may involve cn.jr.dao.SeckillDAO.queryById
### The error occurred while executing a query
### Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Could not get JDBC Connection; nested exception is java.sql.SQLException: An attempt by a client to checkout a Connection has timed out.
 at org.apache.ibatis.exceptions.ExceptionFactory.wrapException(ExceptionFactory.java:30)
 at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:150)
 at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:141)
 at org.apache.ibatis.session.defaults.DefaultSqlSession.selectOne(DefaultSqlSession.java:77)
 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
 at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
 at java.lang.reflect.Method.invoke(Method.java:498)
 at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:433)
 ... 35 more
Caused by: org.springframework.jdbc.CannotGetJdbcConnectionException: Could not get JDBC Connection; nested exception is java.sql.SQLException: An attempt by a client to checkout a Connection has timed out.
 at org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:80)
 at org.mybatis.spring.transaction.SpringManagedTransaction.openConnection(SpringManagedTransaction.java:82)
 at org.mybatis.spring.transaction.SpringManagedTransaction.getConnection(SpringManagedTransaction.java:68)
 at org.apache.ibatis.executor.BaseExecutor.getConnection(BaseExecutor.java:336)
 at org.apache.ibatis.executor.SimpleExecutor.prepareStatement(SimpleExecutor.java:84)
 at org.apache.ibatis.executor.SimpleExecutor.doQuery(SimpleExecutor.java:62)
 at org.apache.ibatis.executor.BaseExecutor.queryFromDatabase(BaseExecutor.java:324)
 at org.apache.ibatis.executor.BaseExecutor.query(BaseExecutor.java:156)
 at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:109)
 at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:83)
 at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:148)
 ... 42 more
Caused by: java.sql.SQLException: An attempt by a client to checkout a Connection has timed out.
 at com.mchange.v2.sql.SqlUtils.toSQLException(SqlUtils.java:106)
 at com.mchange.v2.sql.SqlUtils.toSQLException(SqlUtils.java:65)
 at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:527)
 at com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource.getConnection(AbstractPoolBackedDataSource.java:128)
 at org.springframework.jdbc.datasource.DataSourceUtils.doGetConnection(DataSourceUtils.java:111)
 at org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:77)
 ... 52 more
Caused by: com.mchange.v2.resourcepool.TimeoutException: A client timed out while waiting to acquire a resource from com.mchange.v2.resourcepool.BasicResourcePool@909217e -- timeout at awaitAvailable()
 at com.mchange.v2.resourcepool.BasicResourcePool.awaitAvailable(BasicResourcePool.java:1317)
 at com.mchange.v2.resourcepool.BasicResourcePool.prelimCheckoutResource(BasicResourcePool.java:557)
 at com.mchange.v2.resourcepool.BasicResourcePool.checkoutResource(BasicResourcePool.java:477)
 at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:525)
 ... 55 more