refactor(samples): convert sample tests from ava to mocha

[nareshqlogic]

Fixes convert all sample tests from ava to mocha #2865 (it's a good idea to open an issue first for discussion)

• Tests and linter pass
• Code coverage does not decrease (if any source code was changed)
• Appropriate docs were updated (if necessary)

[JustinBeckwith]

All looks good except for the 2 comments :)

[JustinBeckwith]

Looks like a few interesting test failures:

  7 passing (6s)
  3 failing
  1) should synthesize audio from ssml:
      AssertionError [ERR_ASSERTION]: true === false
      + expected - actual
      -true
      +false
      at Context.it (system-test/synthesize.test.js:54:10)
  2) should synthesize audio from text file:
      AssertionError [ERR_ASSERTION]: true === false
      + expected - actual
      -true
      +false
      at Context.it (system-test/synthesize.test.js:64:10)
  3) should synthesize audio from ssml file:
      AssertionError [ERR_ASSERTION]: true === false
      + expected - actual
      -true
      +false
      at Context.it (system-test/synthesize.test.js:74:10)
(node:108) [DEP0013] DeprecationWarning: Calling an asynchronous function without callback is deprecated.
(node:108) [DEP0013] DeprecationWarning: Calling an asynchronous function without callback is deprecated.
(node:108) [DEP0013] DeprecationWarning: Calling an asynchronous function without callback is deprecated.
(node:108) [DEP0013] DeprecationWarning: Calling an asynchronous function without callback is deprecated.
(node:108) [DEP0013] DeprecationWarning: Calling an asynchronous function without callback is deprecated.

[nareshqlogic]

Hi @JustinBeckwith ,
I think file unlink should be executed after each test case as it is creating same file(test-output.mp3) in each one test case. So I changed from after to afterEach block. Let me correct if I am wrong.

[JustinBeckwith]

Sounds good to me, but we probably want to make sure it actually exists first, or wrap the unlink in a try/catch :)

  1 passing (787ms)
  1 failing
  1) "after each" hook:
     Uncaught Error: ENOENT: no such file or directory, unlink 'test-output.mp3'

[nareshqlogic]

Thank you Justin. I warped the unlink in a try/catch.