Test Format

Gabbi tests are expressed in YAML as a series of HTTP requests with their expected response:

   - name: retrieve root
     GET: /
     status: 200

This will trigger a GET request to / on the configured Target Host. The test will pass if the response’s status code is 200.

Test Structure

The top-level tests category contains an ordered sequence of test declarations, each describing the expected response to a given request:






The test’s name. Must be unique within a file.



An arbitrary string describing the test.


If True or all (synonymous), prints a representation of the current request and response to stdout, including both headers and body. If set to headers or body, only the corresponding part of the request and response will be printed. If the output is a TTY, colors will be used. If the body content-type is JSON it will be formatted for improved readability. See VerboseHttp for details.

defaults to False


A string message which if set will cause the test to be skipped with the provided message.

defaults to False


Determines whether to expect this test to fail. Note that the test will be run anyway.

defaults to False


Determines if this test will be run in sequence (after) the test prior to it in the list of tests within a file. To be concrete, when this is True the test is dependent on the prior test and if that prior has not yet run, it wil be run, even if only the current test has been selected. Set this to False to allow selecting a test without dependencies.

defaults to True


States whether the underlying HTTP client should attempt to validate SSL certificates. In many test environment certificates will be self-signed so changing this may be requried. It can also be changed when Loading and Running Tests or using gabbi-run.

defaults to True


Sets a timeout (in seconds) for the HTTP request.

defaults to 30 seconds


If True, means that the response body will not be processed to Python data. This can be necessary if a response claims a content-type but the body is not actually that type but it is still necessary to run tests against the response. In that situation, if disable_response_handler is False the test will be treated as a failure.

defaults to False


When tests are generated dynamically, the TestCase name will include the respective test’s name, lowercased with spaces transformed to _. In at least some test runners this will allow you to select and filter on test name.

Request Parameters




any uppercase string

Any such key is considered an HTTP method, with the corresponding value expressing the URL.

This is a shortcut combining method and url into a single statement:

GET: /index

corresponds to:

method: GET
url: /index


The HTTP request method.

defaults to GET


The URL to request. This can either be a full path (e.g. “/index”) or a fully qualified URL (i.e. including host and scheme, e.g. “http://example.org/index”) — see Target Host for details.

Either this or the shortcut above is required


A dictionary of key-value pairs representing request header names and values. These will be added to the constructed request.


A dictionary of query parameters that will be added to the url as query string. If that URL already contains a set of query parameters, those wil be extended. See Example Tests for a demonstration of how the data is structured.


A representation to pass as the body of a request. Note that content-type in request_headers should also be set — see Data for details.


If True, redirects will automatically be followed.

defaults to False


Determines whether the request uses SSL (i.e. HTTPS). Note that the url’s scheme takes precedence if present — see Target Host for details.

defaults to False

Response Expectations





The expected response status code. Multiple acceptable response codes may be provided, separated by || (e.g. 302 || 301 — note, however, that this indicates ambiguity, which is generally undesirable).

defaults to 200


A dictionary of key-value pairs representing expected response header names and values. If a header’s value is wrapped in /.../, it will be treated as a regular expression to search for in the response header.


A list of headers which must not be present.


A list of string fragments expected to be present in the response body.


A dictionary of JSONPath rules paired with expected matches. Using this rule requires that the content being sent from the server is JSON (i.e. a content type of application/json or containing +json)

If the value is wrapped in /.../ the result of the JSONPath query will be searched for the value as a regular expression.


A dictionary of two keys:

  • count: An integer stating the number of times to attempt this test before giving up.

  • delay: A floating point number of seconds to delay between attempts.

This makes it possible to poll for a resource created via an asynchronous request. Use with caution.

Note that many of these items allow substitutions.

Default values for a file’s tests may be provided via the top-level defaults category. These take precedence over the global defaults (explained below).

For examples see the gabbi tests, Example Tests and the gabbi-demo tutorial.


The top-level fixtures category contains a sequence of named Fixtures.

Response Handlers

response_* keys are examples of Response Handlers. Custom handlers may be created by test authors for specific use cases. See Content Handlers for more information.


There are a number of magical variables that can be used to make reference to the state of a current test, the one just prior or any test prior to the current one. The variables are replaced with real values during test processing.


  • $ENVIRON['<environment variable>']: The name of an environment variable. Its value will replace the magical variable. If the string value of the environment variable is "True" or "False" then the resulting value will be the corresponding boolean, not a string.

Current Test

  • $SCHEME: The current scheme/protocol (usually http or https).

  • $NETLOC: The host and potentially port of the request.

Immediately Prior Test

  • $COOKIE: All the cookies set by any Set-Cookie headers in the prior response, including only the cookie key and value pairs and no metadata (e.g. expires or domain).

  • $URL: The URL defined in the prior request, after substitutions have been made. For backwards compatibility with earlier releases $LAST_URL may also be used, but if $HISTORY (see below) is being used, $URL must be used.

  • $LOCATION: The location header returned in the prior response.

  • $HEADERS['<header>']: The value of any header from the prior response.

  • $RESPONSE['<json path>']: A JSONPath query into the prior response. See JSONPath for more on formatting.

Any Previous Test

  • $HISTORY['<test name>'].<magical variable expression>: Any variable which refers to a prior test may be used in an expression that refers to any earlier test in the same file by identifying the target test by its name in a $HISTORY dictionary. For example, to refer to a value in a JSON object in the response of a test named post json:

    $HISTORY['post json'].$RESPONSE['$.key']

    This is a very powerful feature that could lead to test that are difficult for humans to read. Take care to optimize for the maintainers that will come after you, not yourself.


For $ENVIRON and $RESPONSE it is possible to attempt to cast the value to another type: int, float, str, or bool. If the cast fails an exception will be raised and the test will fail.

This functionality only works when the magical variable is the whole value of a YAML entry. If the variable is intermixed with other data, an exception will be raised and the test will fail.

The format for a cast is to append a : and the cast type after the type of the magical variable. For example:



Prior to the introduction of this feature, $ENVIRON would already do some automatic casting of numbers to ints and floats and the strings True and False to booleans. This continues to be the case, but only if no cast is provided.


Where a single-quote character, ', is shown in the variables above you may also use a double-quote character, ", but in any given expression the same character must be used at both ends.

All of these variables may be used in all of the following fields:

  • skip

  • url

  • query_parameters

  • data

  • request_headers (in both the key and value)

  • response_strings

  • response_json_paths (in both the key and value, see json path substitution for more info)

  • response_headers (in both the key and value)

  • response_forbidden_headers

  • count and delay fields of poll

With these variables it ought to be possible to traverse an API without any explicit statements about the URLs being used. If you need a replacement on a field that is not currently supported please raise an issue or provide a patch.

As all of these features needed to be tested in the development of gabbi itself, the gabbi tests are a good source of examples on how to use the functionality. See also Example Tests for a collection of examples and the gabbi-demo tutorial.


The data key has some special handing to allow for a bit more flexibility when doing a POST or PUT:

  • If the value is not a string (that is, it is a sequence or structure) it is treated as a data structure that will be turned into a string by the dumps method on the relevant content handler. For example if the content-type of the body is application/json the data structure will be turned into a JSON string.

  • If the value is a string that begins with <@ then the rest of the string is treated as a filepath to be loaded. The path is relative to the test directory and may not traverse up into parent directories.

  • If the value is an undecorated string, that’s the value.


When reading from a file care should be taken to ensure that a reasonable content-type is set for the data as this will control if any encoding is done of the resulting string value. If it is text, json, xml or javascript it will be encoded to UTF-8.