There doesn't seem to be a common thread. Some of the tests do seem flaky but I can't get the same projects to pass. One error is a mock interaction:

1) collectGarbage(com.squareup.mailbox.jobs.CollectGarbageActionTest)
                     org.mockito.exceptions.verification.NoInteractionsWanted: 
                     No interactions wanted here:
                     -> at com.squareup.mailbox.jobs.CollectGarbageActionTest.verifyGarbageCollection(CollectGarbageActionTest.java:89)
                     But found this interaction on mock 'fileDeleter':
                     -> at com.squareup.mailbox.jobs.CollectGarbageAction$TrashCollectionEnvironment.deleteFile(CollectGarbageAction.java:98)

another is

Caused by: org.bouncycastle.openssl.PEMException: Unable to create OpenSSL PBDKF: PBKDF-OpenSSL SecretKeyFactory not available

another seems to relate to a timestamp comparison. I'm wondering if this isn't classpath related.