Missing dependencies with grails persistent engine type "mapping"

[dforegger]

When running with the Mongo GORM Persistence Engine to "mapping" using grails:engine:mongodb:mapping, a ClassNotFound exception is thrown for FileUtils from apache-commons:io

h2. Steps to reproduce

1. On grails 3.3.2, run "grails create-app "
2. Per the set-up instructions: add
   compile 'org.grails.plugins:mongodb:6.1.2' and testCompile "org.grails.plugins:embedded-mongodb:1.0.2" to the dependencies { ... } block and configure the grails-app/init/Application.groovy class with @EnableAutoConfiguration(exclude = [EmbeddedMongoAutoConfiguration])
3. Modify application.yml to include environments: test: grails: mongodb: engine: "mapping"
4. Create a new domain object: grails create-domain-class Foo and add a property to it String bar
5. Create a new integration test: grails create-integration-test Foo
6. Update the integration test to save and flush an instance of Foo
7. Run tests: grails test-app -integration

Expect: Tests pass without error
Result: Console prints:

embedded.mongo.transitive.test.FooSpec > classMethod FAILED
java.lang.IllegalArgumentException
Exception in thread "Thread-5" java.lang.NoClassDefFoundError: org/apache/commons/io/FileUtils
at de.flapdoodle.embed.process.io.file.Files.forceDelete(Files.java:119)
at de.flapdoodle.embed.mongo.MongodProcess.deleteTempFiles(MongodProcess.java:92)
at de.flapdoodle.embed.mongo.AbstractMongoProcess.cleanupInternal(AbstractMongoProcess.java:124)
at de.flapdoodle.embed.process.runtime.AbstractProcess.stop(AbstractProcess.java:172)
at de.flapdoodle.embed.process.runtime.Executable.stop(Executable.java:73)
at de.flapdoodle.embed.process.runtime.Executable$JobKiller.run(Executable.java:90)
at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.ClassNotFoundException: org.apache.commons.io.FileUtils
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:335)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 7 more

Final notes:

• I'm seeing mixed results with this - sometimes this prints and tests fail, sometimes it prints and they pass, and sometimes it doesn't print at all. I'm still working to figure out each case, but ran out of time.
• I was also seeing a similar issues with a dependency on commons-compress, which is what I was originally trying to reproduce, but I haven't been able to successfully reproduce it in a clean application yet.