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Table of Contents

What Is It?

  • A REST testing and API microbenchmarking tool
  • Tests are defined in basic YAML or JSON config files, no code needed
  • Minimal dependencies (pycurl, pyyaml, optionally future), making it easy to deploy on-server for smoketests/healthchecks
  • Supports generate/extract/validate mechanisms to create full test scenarios
  • Returns exit codes on failure, to slot into automated configuration management/orchestration tools (also supplies parseable logs)
  • Logic is written and extensible in Python


NEW: Full Python 3 Support in Alpha - download it, 'pip install future' and give it a try!

Apache License, Version 2.0

Status Badge PyPI version PyPI

Join the chat at

Changelog shows the past and present, milestones show the future roadmap.

  • The changelog will also show features/fixes currently merged to the master branch but not released to PyPi yet (pending installation tests across platforms).


PyRestTest works on Linux or Mac with Python 2.6, 2.7, or 3.3+ (with module 'future' installed)

First we need to install package python-pycurl:

  • Ubuntu/Debian: (sudo) apt-get install python-pycurl
  • CentOS/RHEL: (sudo) yum install python-pycurl
  • Mac: don't worry about it
  • Other platforms: unsupported. You may get it to work by installing pycurl & pyyaml manually. Also include 'future' for Python 3. No guarantees though. This is needed because the pycurl dependency may fail to install by pip. In *very rare cases you may need to intall python-pyyaml if pip cannot install it correctly.*

It is easy to install the latest release by pip: (sudo) pip install pyresttest (also install 'future' if on Python 3)

If pip isn't installed, we'll want to install it first: If that is not installed, we'll need to install it first:

  • Ubuntu/Debian: (sudo) apt-get install python-pip
  • CentOS/RHEL: (sudo) yum install python-pip
  • Mac OS X with homebrew: brew install python (it's included)
  • Or with just python installed: wget && sudo python

Releases occur every few months, if you want to use unreleased features, it's easy to install from source:

See the Change Log for feature status.

git clone
cd pyresttest
sudo python install

The master branch tracks the latest; it is unit tested, but less stable than the releases (the 'stable' branch tracks tested releases).

Troubleshooting Installation

Almost all installation issues are due to problems with PyCurl and PyCurl's native libcurl bindings. It is easy to check if PyCurl is installed correctly:

python -c 'import pycurl'

If this returns correctly, pycurl is installed, if you see an ImportError or similar, it isn't. You may also verify the pyyaml installation as well, since that can fail to install by pip in rare circumstances.

Error installing by pip

__main__.ConfigurationError: Could not run curl-config: [Errno 2] No such file or directory

This is caused by libcurl not being installed or recognized: first install pycurl using native packages as above. Alternately, try installing just the libcurl libraries:

  • On Ubuntu/Debian: sudo apt-get install libcurl4-openssl-dev
  • On CentOS/RHEL: yum install libcurl-devel

VirtualEnv installation

PyCurl should install by pip, but sometimes has issues with pycurl/libcurl. Manually copying in a working system pycurl installation may help:

cp /usr/lib/python2.7/dist-packages/pycurl* env/local/lib/python2.7/site-packages/

Sample Test

This will check that APIs accept operations, and will smoketest an application

- config:
    - testset: "Basic tests"
    - timeout: 100  # Increase timeout from the default 10 seconds
- test: 
    - name: "Basic get"
    - url: "/api/person/"
- test: 
    - name: "Get single person"
    - url: "/api/person/1/"
- test: 
    - name: "Delete a single person, verify that works"
    - url: "/api/person/1/"
    - method: 'DELETE'
- test: # create entity by PUT
    - name: "Create/update person"
    - url: "/api/person/1/"
    - method: "PUT"
    - body: '{"first_name": "Gaius","id": 1,"last_name": "Baltar","login": "gbaltar"}'
    - headers: {'Content-Type': 'application/json'}
    - validators:  # This is how we do more complex testing!
        - compare: {header: content-type, comparator: contains, expected:'json'}
        - compare: {jsonpath_mini: 'login', expected: 'gbaltar'}  # JSON extraction
        - compare: {raw_body:"", comparator:contains, expected: 'Baltar' }  # Tests on raw response
- test: # create entity by POST
    - name: "Create person"
    - url: "/api/person/"
    - method: "POST"
    - body: '{"first_name": "William","last_name": "Adama","login": "theadmiral"}'
    - headers: {Content-Type: application/json}


  • The Quickstart should be everyone's starting point
  • Here's a really good example for how to create a user and then do tests on it.
    • This shows how to use extraction from responses, templating, and different test types
  • If you're trying to do something fancy, take a look at the content-test.yaml.
    • This shows most kinds of templating & variable uses. It shows how to read from file, using a variable in the file path, and templating on its content!
  • PyRestTest isn't limited to JSON; there's an example for submitting form data
  • There's a whole folder of example tests to help get started

How Do I Use It?

Running A Simple Test

Run a basic test of the github API:

pyresttest examples/github_api_smoketest.yaml

Using JSON Validation

A simple set of tests that show how json validation can be used to check contents of a response. Test includes both successful and unsuccessful validation using github API.

pyresttest examples/github_api_test.yaml

(For help: pyresttest --help )

Interactive Mode

Same as the other test but running in interactive mode.

pyresttest examples/github_api_test.yaml --interactive true --print-bodies true

Verbose Output

pyresttest examples/github_api_test.yaml --log debug

Other Goodies

  • Simple templating of HTTP request bodies, URLs, and validators, with user variables
  • Generators to create dummy data for testing, with support for easily writing your own
  • Sequential tests: extract info from one test to use in the next
  • Import test sets in other test sets, to compose suites of tests easily
  • Easy benchmarking: convert any test to a benchmark, by changing the element type and setting output options if needed
  • Lightweight benchmarking: ~0.3 ms of overhead per request, and plans to reduce that in the future
  • Accurate benchmarking: network measurements come from native code in LibCurl, so test overhead doesn't alter them
  • Optional interactive mode for debugging and demos

Basic Test Set Syntax

As you can see, tests are defined in YAML format.

There are 5 top level test syntax elements:

  • url: a simple test, fetches given url via GET request and checks for good response code
  • test: a fully defined test (see below)
  • benchmark: a fully defined benchmark (see below)
  • config or configuration: overall test configuration (timeout is the most common option)
  • import: import another test set file so you Don't Repeat Yourself

Import example

# Will load the test sets from miniapp-test.yaml and run them
# Note that this will run AFTER the current test set is executed
# Also note that imported tests get a new Context: any variables defined will be lost between test sets
- import: examples/miniapp-test.yaml

Imports are intended to let you create top-level test suites that run many independent, isolated test scenarios (test sets). They may also be used to create sample data or perform cleanup as long as you don't rely on variables to store this information. For example, if one testset creates a user for a set of scenarios, tests that rely on that user's ID need to start by querying the API to get the ID.

Url Test With Timeout

A simple URL test is equivalent to a basic GET test with that URL. Also shows how to use the timeout option in testset config to descrease the default timeout from 10 seconds to 1.

- config:
    - testset: "Basic tests"
    - timeout: 1
- url: "/api/person/"  # This is a simple test
- test: 
    - url: "/api/person/"  # This does the same thing

Custom HTTP Options (special curl settings)

For advanced cases (example: SSL client certs), sometimes you will want to use custom Curl settings that don't have a corresponding option in PyRestTest.

This is easy to do: for each test, you can specify custom Curl arguments with 'curl_option_optionname.' For this, 'optionname' is case-insensitive and the optionname is a Curl Easy Option with 'CURLOPT_' removed.

For example, to follow redirects up to 5 times (CURLOPT_FOLLOWLOCATION and CURLOPT_MAXREDIRS):

- test: 
    - url: "/api/person/1"
    - curl_option_followlocation: True
    - curl_option_maxredirs: 5  

Note that while option names are validated, no validation is done on their values.

Syntax Limitations

  • Whenever possible, the YAML configuration handler tries to convert variable types as needed. We're all responsible adults, don't do anything crazy and it will play nicely.
  • Only a handful of elements can use dynamic variables (URLs, headers, request bodies, validators) - there are plans to change this in the next few releases.
  • The templating is quite limited (it's doing simple string subsitution). There are plans to improve this in the next few releases, but it isn't there yet.
  • One caveat: if you define the same element (example, URL) twice in the same enclosing element, the last value will be used. In order to preserve sanity, I use last-value wins.
  • No support for "for-each" on requests/responses natively - this can be done via custom extensions, and may be available in the distant future but it's a while out.


Oh, yes please! PyRestTest allows you to collect low-level network performance metrics from Curl itself.

Benchmarks are based off of tests: they extend the configuration elements in a test, allowing you to configure the REST call similarly. However, they do not perform validation on the HTTP response, instead they collect metrics.

There are a few custom configuration options specific to benchmarks:

  • warmup_runs: (default 10 if unspecified) run the benchmark calls this many times before starting to collect data, to allow for JVM warmup, caching, etc
  • benchmark_runs: (default 100 if unspecified) run the benchmark this many times to collect data
  • output_file: (default is None) file name to write benchmark output to, will get overwritten with each run, if none given, will write to terminal only
  • output_format: (default CSV if unspecified) format to write the results in ('json' or 'csv'). More on this below.
  • metrics: which metrics to gather (explained below), MUST be specified or benchmark will do nothing


There are two ways to collect performance metrics: raw data, and aggregated stats. Each metric may yield raw data, plus one or more aggregate values.

  • Raw Data: returns an array of values, one for each benchmark run
  • Aggregates: runs a reduction function to return a single value over the entire benchmark run (median, average, etc)

To return raw data, in the 'metrics' configuration element, simply input the metric name in a list of values. The example below will return raw data for total time and size of download (101 values each).

- benchmark: # create entity
    - name: "Basic get"
    - url: "/api/person/"
    - warmup_runs: 7
    - 'benchmark_runs': '101'
    - output_file: 'miniapp-benchmark.csv'
    - metrics:
        - total_time
        - size_download

Aggregates are pretty straightforward:

  • mean or mean_arithmetic: arithmetic mean of data (normal 'average')
  • mean_harmonic: harmonic mean of data (useful for rates)
  • median: median, the value in the middle of sorted result set
  • std_deviation: standard deviation of values, useful for measuring how consistent they are
  • total or sum: total up the values given

Currently supported metrics are listed below, and these are a subset of Curl get_info variables. These variables are explained here (with the CURLINFO_ prefix removed): curl_easy_get_info documentation

Metrics: 'appconnect_time', 'connect_time', 'namelookup_time', 'num_connects', 'pretransfer_time', 'redirect_count', 'redirect_time', 'request_size', 'size_download', 'size_upload', 'speed_download', 'speed_upload', 'starttransfer_time', 'total_time'

Benchmark report formats:

CSV is the default report format. CSV ouput will include:

  • Benchmark name
  • Benchmark group
  • Benchmark failure count (raw HTTP failures)
  • Raw data arrays, as a table, with headers being the metric name, sorted alphabetically
  • Aggregates: a table of results in the format of (metricname, aggregate_name, result)

In JSON, the data is structured slightly differently:

{"failures": 0,
    [["metric_name", "aggregate", "aggregateValue"] ...],
"failures": failureCount,
"group": "Default",
"results": {"total_time": [value1, value2, etc], "metric2":[value1, value2, etc], ... }


- config:
    - testset: "Benchmark tests using test app"

- benchmark: # create entity
    - name: "Basic get"
    - url: "/api/person/"
    - warmup_runs: 7
    - 'benchmark_runs': '101'
    - output_file: 'miniapp-benchmark.csv'
    - metrics:
        - total_time
        - total_time: mean
        - total_time: median
        - size_download
        - speed_download: median

- benchmark: # create entity
    - name: "Get single person"
    - url: "/api/person/1/"
    - metrics: {speed_upload: median, speed_download: median, redirect_time: mean}
    - output_format: json
    - output_file: 'miniapp-single.json'

RPM-based installation

Pure RPM-based install?

It's easy to build and install from RPM:

Building the RPM:

python bdist_rpm  # Build RPM
find -iname '*.rpm'   # Gets the RPM name

Installing from RPM

sudo yum localinstall my_rpm_name
sudo yum install PyYAML python-pycurl  # If using python3, needs 'future' too
  • You need to install PyYAML & PyCurl manually because Python distutils can't translate python dependencies to RPM packages.

Gotcha: Python distutils add a dependency on your major python version. This means you can't build an RPM for a system with Python 2.6 on a Python 2.7 system.

Building an RPM for RHEL 6/CentOS 6

You'll need to install rpm-build, and then it should work.

sudo yum install rpm-build

Project Policies

  • PyRestTest uses the Github flow
    • The master branch is an integration branch for mature features
    • Releases are cut periodically from master (every 3-6 months generally, or more often if breaking bugs are present) and released to PyPi
    • Feature development is done in feature branches and merged to master by PR when tested (validated by continuous integration in Jenkins)
    • The 'stable' branch tracks the last release, use this if you want to run PyRestTest from source
  • The changelog is here, this will show past releases and features merged to master for the next release but not released
  • Testing: tested on Ubuntu 14/python 2.7 and CentOS 6/python 6.6, plus Debian Wheezy for Python 3.4.3
  • Releases occur every few months to PyPi once a few features are ready to go
  • PyRestTest uses Semantic Versioning 2.0
  • Back-compatibility is important! PyRestTest makes a strong effort to maintain command-line and YAML format back-compatibility since 1.0.
    • Extension method signatures are maintained as much as possible.
    • However, internal python implementations are subject to change.
    • Major version releases (1.x to 2.x, etc) may introduce breaking API changes, but only with a really darned good reason, and only there's not another way.

Feedback and Contributions

We welcome any feedback you have, including pull requests, reported issues, etc!

For new contributors there are a whole set of issues labelled with help wanted which are excellent starting points to offer a contribution!

For instructions on how to set up a dev environment for PyRestTest, see

For pull requests to get easily merged, please:

  • Include unit tests (and functional tests, as appropriate) and verify that passes
  • Include documentation as appropriate
  • Attempt to adhere to PEP8 style guidelines and project style

Bear in mind that this is largely a one-man, outside-of-working-hours effort at the moment, so response times will vary. That said: every feature request gets heard, and even if it takes a while, all the reasonable features will get incorporated. If you fork the main repo, check back periodically... you may discover that the next release includes something to meet your needs and then some!


Why not pure-python tests?

  • This is written for an environment where Python is not the sole or primary language
  • You totally can do pure-Python tests if you want!
    • Extensions provide a stable API for adding more complex functionality in python
    • All modules can be imported and used as libraries
    • Gotcha: the project is still young, so internal implementation may change often, much more than YAML features

Why YAML and not XML/JSON?

  • XML is extremely verbose and has many gotchas for parsing
  • You CAN use JSON for tests, it's a subset of YAML. See miniapp-test.json for an example.
  • YAML tends to be the most concise, natural, and easy to write of these three options

Does it do load tests?

  • No, this is a separate niche and there are already many excellent tools to fill it
  • Adding load testing features would greatly increase complexity
  • But some form might come eventually!

Why do you use PyCurl and not requests?

  • Maybe eventually. PyRestTest needs the low-level features of PyCurl for benchmarking, and benefits from its performance. However we may eventually abstract some of the core testing features away to allow for pure-python execution