anchor.diff:  also checks to ensure that there are no user cycles generated when we are
   running in kernel mode, which could be caused by a hung progress.
   
  +=== [[leaks]] Memory Leak Detection
   
   === Running multiple tests and dependencies
   
  
positive.code: Some tests will consist of multiple commands, and such tests are designed to
  stress test your system.
  
  === [[targets]]Targets
  
  Target files (`*.tt`) are located in the `targets/` directory in your test161 root
  directory. Targets specify which tests are run for each assignment, and
  how the scoring is distributed. When you `test161 submit` your assignments, you will
  specify which target to submit to.
  
  == Features
  
  === Testfile Syntactic Sugar
  
  A line starting with `$` will be run in the shell and start the shell as
  needed. Lines not starting with `$` are run from the kernel prompt and get
  there if necessary by exiting the shell. `sys161` shuts down cleanly without
  requiring the test manually exit the shell and kernel, as needed.
  
  So this test:
  ....
  $ /bin/true
  ....
  
  Expands to:
  ....
  s
  /bin/true
  exit
  q
  ....
  
  *Note that commands run in the shell _must_ be prefixed with `$`.* Otherwise
  `test161` will consider them a kernel command and exit the shell before
  running them. For example:
  
  This test is probably not what you want:
  ....
  s
  /bin/true
  ....
  
  Because it will expand to:
  ....
  s
  exit
  /bin/true # not a kernel command
  ....
  
  But this is so much simpler, right?
  ....
  $ /bin/true
  ....
  
  === [[tags]]Test Tags
  Optionally, tests can have one or more tags. `test161` can be invoked to run these tests
  as a group with `test161 run <tag>`.
  
  === Progress Tracking Using `stat161` Output
  
  
negative.code: arguments. A *test* consists of one or more OS/161 commands along with
  metadata, `sys161` configuration, and possibly some additional `test161` runtime
  configuration. Tests can include one or more *tags*, which allow related tests
  to be grouped and run together. *Targets* consist of a set of tests that are run
  together and allow point values to be assigned to tests.
  
  ==== Listing Tests, Targets, and Tags
  