(0.  If you want to do code-coverage in an addon, AND are willing to live
with these restrictions:

a.  no 'each' or other E4X extensions
b.  no conditional 'let'
c.  no conditional 'catch'

here is a method:  
https://github.com/gregglind/lotsa_addons/tree/master/testy)

Below are some partial notes on my attempts to instrument the sdk itself.  
I have tried two methods:

    cfx test --pkg-dir=fakey  #  complains about duplicate module errors

As an alternative, I tried to make a complete copy of the `addon-sdk`.  
There is some subset of modules that needs to be uninstrumented, so the
whole system can load, but I am not sure of what those are!

   ->  Bootstrap error: cannot find the global scope in
for:,addon-sdk/lib/sdk/system/events.js

```
    # let's instrument the sdk itself!

    ## gross to use a for-loop, but couldn't get this working in xargs
    # http://www.dwheeler.com/essays/filenames-in-shell.html

    cd directory/above/addon-sdk
    npm install git://github.com/gregglind/CoverJS.git#moz  # installs
moz-aware dependencies [1]

    rm -rf addon-sdk-test && cp -r addon-sdk addon-sdk-test &&
    ((cd addon-sdk && find lib -name '*js' -print0 && cd ..) | while IFS=""
read -r -d "" file ; do
       ./node_modules/coverjs-moz/bin/coverjs -o addon-sdk-test/`dirname
"$file"` --escodegen-options
'{"moz":{"starlessGenerator":true,"parenthesizedComprehensionBlock":true}}'
addon-sdk/"$file";
    done ) &> addon-sdk-test/instrument.log
    cd addon-sdk-test

    # this list is incomplete
    yes | cp {../addon-sdk/,}lib/sdk/deprecated/memory.js
    yes | cp {../addon-sdk/,}lib/sdk/loader/cuddlefish.js
    yes | cp {../addon-sdk/,}lib/toolkit/loader.js
    yes | cp {../addon-sdk/,}lib/sdk/test/harness.js
    yes | cp {../addon-sdk/,}lib/sdk/addon/runner.js
    yes | cp {../addon-sdk/,}lib/sdk/system/events.js
    yes | cp {../addon-sdk/,}lib/sdk/util/object.js

    ( ./bin/cfx test  ) 2>&1 | less
```