If directory is specified test if it's a valid one.

Submitted By: "Nico Seessle" <Nico.Seessle@epost.de>


git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@268493 13f79535-47bb-0310-9956-ffa450edef68

src/main/org/apache/tools/ant/taskdefs/ExecTask.java

@@ -170,6 +170,12 @@ public class ExecTask extends Task {
         if (cmdl.getExecutable() == null) {
             throw new BuildException("no executable specified", location);
         }
+        if (dir != null && !dir.exists()) {
+        	throw new BuildException("The directory you specified does not exist");
+        }
+        if (dir != null && !dir.isDirectory()) {
+        	throw new BuildException("The directory you specified is not a directory");
+        }
     }
 
     /**