This test uses pinDateTime to create an history of test results where tests
have been executed in order test suite 1, 2, 3.
This is done using this pattern:

      now = DateTime()
      ... # do several things that may actually take more than one second
      self.processTest("test suite 1", "r0=a", node_title="COMP0-Node1")
      self.pinDateTime(now + 1.0/86400)
      self.processTest("test suite 2", "r0=a", node_title="COMP1-Node1")
      self.pinDateTime(now + 2.0/86400)
      self.processTest("test suite 3", "r0=a", node_title="COMP1-Node1")

My guess is that we take "now" too early, and when we add 1 second to this
now variable, this may actually be going back in time sometimes, effectively
creating test suite 2 before test suite 1.

Assign now to current date after doing all the affectTestSuite calls should
solve this.