Q: What is the correct structure for using mocha to test your package? Right now I have:
Package.describe({
  name: 'parlay:synapsepay',
  version: '0.0.1',
  summary: 'synapse_pay_rest for Meteor',
  git: 'https://github.com/parlaywithme/meteor-synapsepay',
  documentation: 'README.md'
});

Package.onUse(function(api) {
  api.versionsFrom('1.2.0.2');
  api.use('coffeescript');
  api.addFiles('synapsepay.coffee');
});

Package.onTest(function(api) {
  api.use('coffeescript');
  api.use('mike:mocha-package');
  api.use('parlay:synapsepay');
  api.addFiles('synapsepay-tests.coffee');
});

and
MochaWeb?.testOnly ->
  describe 'sanity', ->
    it 'is visible', ->
      chai.assert.isDefined SynapsePay

https://github.com/parlaywithme/meteor-synapsepay
I'm getting a has no method 'testOnly' error, running 
meteor test-packages ./

inside packages/meteor-synapsepay:
ERROR: packages.json parsing error [ ENOENT, no such file or directory '/Users/me/parlay/packages/meteor-synapsepay/packages.json' ]
[[[[[ Tests ]]]]]                             

=> Started proxy.                             
=> Started MongoDB.                           
W20151018-00:24:58.123(-4)? (STDERR)          
W20151018-00:24:58.125(-4)? (STDERR) /Users/me/.meteor/packages/meteor-tool/.1.1.9.osr2yb++os.osx.x86_64+web.browser+web.cordova/mt-os.osx.x86_64/dev_bundle/server-lib/node_modules/fibers/future.js:245
W20151018-00:24:58.125(-4)? (STDERR)                        throw(ex);
W20151018-00:24:58.125(-4)? (STDERR)                              ^
W20151018-00:24:58.125(-4)? (STDERR) TypeError: Object [object Object] has no method 'testOnly'
W20151018-00:24:58.125(-4)? (STDERR)     at Package (packages/local-test_parlay_synapsepay/synapsepay-tests.coffee:1:11)
W20151018-00:24:58.125(-4)? (STDERR)     at packages/local-test_parlay_synapsepay/synapsepay-tests.coffee:1:1
W20151018-00:24:58.126(-4)? (STDERR)     at packages/local-test_parlay_synapsepay/synapsepay-tests.coffee:1:1
W20151018-00:24:58.126(-4)? (STDERR)     at /private/tmp/meteor-test-run1tbmejw/.meteor/local/build/programs/server/boot.js:242:10
W20151018-00:24:58.126(-4)? (STDERR)     at Array.forEach (native)
W20151018-00:24:58.126(-4)? (STDERR)     at Function._.each._.forEach (/Users/me/.meteor/packages/meteor-tool/.1.1.9.osr2yb++os.osx.x86_64+web.browser+web.cordova/mt-os.osx.x86_64/dev_bundle/server-lib/node_modules/underscore/underscore.js:79:11)
W20151018-00:24:58.126(-4)? (STDERR)     at /private/tmp/meteor-test-run1tbmejw/.meteor/local/build/programs/server/boot.js:137:5
=> Exited with code: 8


A: While poorly documented at the moment, this issue can be solved easily:
Simply ditch testOnly and write your tests directly in your test file.
describe 'sanity', ->
  it 'is visible', ->
    chai.assert.isDefined SynapsePay

Mocha was first designed for application tests. Using it for package tests can prove challenging.
When you will have your tests running, you may also see big Meteor.methods Match errors in the console. It is a common issue that should not interfere with the tests themselves. 
