If an issue type is not passed to the create issue email handler issue creation fails

At the moment if there is not issuetype parameter or the parameter specifies a wrong id of an issue type issue creation fails with:

java.lang.NullPointerException
at com.atlassian.jira.workflow.SimpleWorkflowManager.createIssue(SimpleWorkflowManager.java:128)
at com.atlassian.jira.issue.managers.DefaultIssueManager.createIssue(DefaultIssueManager.java:303)
at com.atlassian.jira.issue.managers.DefaultIssueManager.createIssue(DefaultIssueManager.java:247)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:324)
at com.atlassian.util.profiling.object.ObjectProfiler.profiledInvoke(ObjectProfiler.java:71)
at com.atlassian.jira.config.component.DelegatingInvocationHandler.invoke(DelegatingInvocationHandler.java:27)
at $Proxy2.createIssue(Unknown Source)
at com.atlassian.jira.service.util.handler.CreateIssueHandler.handleMessage(CreateIssueHandler.java:149)
at com.atlassian.jira.service.util.handler.CreateOrCommentHandler.handleMessage(CreateOrCommentHandler.java:119)
at com.atlassian.jira.service.services.mail.MailFetcherService.run(MailFetcherService.java:165)
at com.atlassian.jira.service.JiraServiceContainer.run(JiraServiceContainer.java:59)
at com.atlassian.jira.service.ServiceRunner.execute(ServiceRunner.java:50)
at org.quartz.core.JobRunShell.run(JobRunShell.java:191)
at org.quartz.simpl.SimpleThreadPool$WorkerThread.run(SimpleThreadPool.java:516)

Need to detect error in the same way the project parameter is tested.