Test Suite:
===========

A YAML test file consists of:
* an optional `setup` section, followed by
* one or more test sections

For instance:

    setup:
      - do: ....
      - do: ....

    ---
    "First test":
      - do: ...
      - match: ...

    ---
    "Second test":
      - do: ...
      - match: ...


A `setup` section contains a list of commands to run before each test
section in order to setup the same environment for each test section.

A test section represents an independent test, containing multiple `do`
statements and assertions. The contents of a test section must be run in
order, but individual test sections may be run in any order, as follows:

1. run `setup` (if any)
2. reset the `response` var and the `stash` (see below)
2. run test contents
3. run teardown

The `teardown` should delete all indices and all templates.

Dot notation:
-------------
Dot notation is used for (1) method calls and (2) hierarchical data structures.  For
instance, a method call like `cluster.health` would do the equivalent of:

    client.cluster.health(...params...)

A test against `_tokens.1.token` would examine the `token` key, in the second element
of the `tokens` array, inside the `response` var (see below):

    $val = $response->{tokens}[1]{token}  # Perl syntax roolz!

If one of the levels (eg `tokens`) does not exist, it should return an undefined value.
If no field name is given (ie the empty string) then return the current
$val -- used for testing the whole response body.

Use \. to specify paths that actually contain '.' in the key name, for example
in the `indices.get_settings` API.

Skipping tests:
---------------
If a test section should only be run on certain versions of Elasticsearch,
then the first entry in the section (after the title) should be called
`skip`, and should contain the range of versions to be
skipped, and the reason why the tests are skipped.  For instance:

....
    "Parent":
     - skip:
          version:     "0 - 0.90.2"
          reason:      Delete ignores the parent param

     - do:
       ... test definitions ...
....

All tests in the file following the skip statement should be skipped if:
`min <= current <= max`.

The `version` range should always have an upper bound. Versions should
either have each version part compared numerically, or should be converted
to a string with sufficient digits to allow string comparison, eg

    0.90.2 -> 000-090-002

Snapshot versions and versions of the form `1.0.0.Beta1` can be treated
as the rounded down version, eg `1.0.0`.

The skip section can also be used to list new features that need to be
supported in order to run a test. This way the up-to-date runners will
run the test, while the ones that don't support the feature yet can
temporarily skip it, and avoid having lots of test failures in the meantime.
Once all runners have implemented the feature, it can be declared supported
by default, thus the related skip sections can be removed from the tests.

....
    "Parent":
     - skip:
          features:    regex

     - do:
       ... test definitions ...
....

The `features` field can either be a string or an array of strings.
The skip section requires to specify either a `version` or a `features` list.

Required operators:
-------------------

=== `do`

The `do` operator calls a method on the client. For instance:

....
    - do:
        cluster.health:
            level: shards
....

The response from the `do` operator should be stored in the `response` var, which
is reset (1) at the beginning of a file or (2) on the next `do`.

If the arguments to `do` include `catch`, then we are expecting an error, which should
be caught and tested.  For instance:

....
    - do:
        catch:        missing
        get:
            index:    test
            type:    test
            id:        1
....

The argument to `catch` can be any of:

[horizontal]
`missing`::     a 404 response from ES
`conflict`::    a 409 response from ES
`request`::     a generic error response from ES
`param`::       a client-side error indicating an unknown parameter has been passed
                to the method
`/foo bar/`::   the text of the error message matches this regular expression

If `catch` is specified, then the `response` var must be cleared, and the test
should fail if no error is thrown.

=== `set`

For some tests, it is necessary to extract a value from the previous `response`, in
order to reuse it in a subsequent `do` and other tests.  For instance, when
testing indexing a document without a specified ID:

....
    - do:
        index:
            index: test
            type:  test
    - set:  { _id: id }   # stash the value of `response._id` as `id`
    - do:
        get:
            index: test
            type:  test
            id:    $id    # replace `$id` with the stashed value
    - match: { _id: $id } # the returned `response._id` matches the stashed `id`
....

The last response obtained gets always stashed automatically as a string, called `body`.
This is useful when needing to test apis that return text rather than json (e.g. cat api),
as it allows to treat the whole body as an ordinary string field.

Note that not only expected values can be retrieved from the stashed values (as in the
example above), but the same goes for actual values:

....
    - match: { $body: /^.+$/ } # the returned `body` matches the provided regex
....

The stash should be reset at the beginning of each test file.

=== `is_true`

The specified key exists and has a true value (ie not `0`, `false`, `undefined`, `null`
or the empty string), eg:

....
    - is_true:  fields._parent  # the _parent key exists in the fields hash and is "true"
....

=== `is_false`

The specified key doesn't exist or has a false value (ie `0`, `false`, `undefined`,
`null` or the empty string), eg:

....
    - is_false:  fields._source  # the _source key doesn't exist in the fields hash or is "false"
....

=== `match`

Used to compare two variables (could be scalars, arrays or hashes).  The two variables
should be identical, eg:

....
    - match: { _source: { foo: bar }}
....

Supports also regular expressions with flag X for more readability (accepts whitespaces and comments):

....
  - match:
      $body: >
               /^  epoch  \s+  timestamp          \s+  count  \s+  \n
                   \d+    \s+  \d{2}:\d{2}:\d{2}  \s+  \d+    \s+  \n  $/
....

=== `lt` and `gt`

Compares two numeric values, eg:

....
    - lt: { fields._ttl: 10000 }  # the `_ttl` value is less than 10,000
....

=== `length`

This depends on the datatype of the value being examined, eg:

....
    - length: { _id: 22    }   # the `_id` string is 22 chars long
    - length: { _tokens: 3 }   # the `_tokens` array has 3 elements
    - length: { _source: 5 }   # the `_source` hash has 5 keys
....

