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OpenAPI Test Templates (oatts)

Generate basic unit test scaffolding for your OpenAPI specification.


This is not an officially supported Google product.

oatts is based off of the swagger-test-templates module and the lessons learned during its development.

This is a work in progress.


The goal of oatts is to provide a standalone module for generating Node.js unit test code scaffolding based on a given OpenAPI specification.

The hope is that by providing such a tool, API developers will be encouraged to test the contract between their spec and backend early, often and continuously as the project grows.


There are a couple ways to use oatts.


Install via npm

npm install --save oatts

Then use it in code

var oatts = require('oatts');

var options = {
    // see "Options" section below for available options

var tests = oatts.generate('/path/to/openapi.yaml', options);


Command line interface

Install globally via npm

npm install -g oatts

Then use in your command line

> oatts generate --help

  Usage: generate [options]

  generate unit test scaffolding for a given OpenAPI/Swagger Spec


    -h, --help                             output usage information
    --host <host>                          target hostname to use in test generation
    -p, --paths <paths>                    comma separated list of paths to generate tests for
    -e, --samples                          generate sample response bodies rather than schema, if applicable
    -s, --spec <spec>                      path to the target OpenAPI/Swagger spec document to consume
    -w, --writeTo <writeTo>                directory to write the generated tests to file
    -c, --consumes <consumes>              consumes/content-type to use in request when applicable to the API resource
    -o, --produces <produces>              produces/accept to use in request when applicable to the API resource
    -u, --customValues <customValues>      custom request values to be used in generation; takes precedent over a customValuesFile
    --customValuesFile <customValuesFile>  path to JSON file with custom request values to be used in generation
    -m, --scheme <scheme>                  which scheme to use if multiple are present in spec
    -t --templates <templateDir>           path to direcotry of custom templates
    -S, --status-codes <statusCodes>       comma separated list of status codes to explicity generate tests for

> oatts generate -s ./path/to/openapi.yaml -w ./output/dir
> ls ./output/dir
pet-test.js  pet-{petId}-uploadImage-test.js  user-test.js 
. . .

Using the result

The resulting test files are built using the mocha testing framework and chakram API testing framework. Thus, you will need both of these dependencies installed in order to run your newly generated tests.

After installing these, you can run the tests with mocha:

# start your API server to test against!!
> mocha --recursive <test directory>

    tests for /goodbye
        tests for get
            ✓ should respond 200 for "Success" (57ms)

    tests for /hello
        tests for get
            ✓ should respond 200 for "Success"

    2 passing (82ms)

Custom Values

Custom values can be supplied through both the command line and a JSON file. The in-line, command line supplied JSON will take precedent.

An example custom values JSON file can be found here.

Custom Templates

Custom templates can be supplied via the templates option. The directory pointed to by the option must contain 4 Handlebars templates named the same way as those found in ./templates.

  • topLevel.handlebars: the top level template for a single test file
  • pathLevel.handlebars: the path level template, usually the beginning of a test suite for a specific path
  • operationLevel.handlebars: the operation level template, for a single operation test suite
  • transactionLevel.handlebars: the template for a single transaction, or a single response code's unit test

The data available to be used in the templates is specified in the ProcessedSpec type.

There are also a few helpers available to be used in the Handlebars templates, which can be found in the templateHelpers documentation namespace. Use the default templates as examples of how to use them.


The following options can be passed to the generation function, some/all are exposed in the accompanying CLI:

Name CLI Flag Default Required Description
spec --spec -s n/a true Path to a swagger.yaml or openapi.yaml
host --host false Hostname to put in test requests; defaults to host in given spec
paths --paths -p spec.paths false API paths to generate tests for; defaults to all paths in given spec
samples --samples -e false false Toggle generating sample responses for assertion
writeTo --writeTo -w n/a false Directory to write generated tests to; will create the directory if it doesn't exist
consumes --consumes -c operation.consumes[0] | | spec.conumes[0] false Consumes header to use in a request when applicable
produces --produces -o operation.produces[0] | | spec.produces[0] false Produces header to use in a request when applicable
customValues --customValues -u n/a false Values to be populated in requests where specified; overrides customValuesFile
customValuesFile --customValuesFile n/a false Path to a JSON file with values to populate in requests
scheme --scheme -m spec.schemes[0] false Override for multiple scheme present in a spec
templates --templates -t './templates' false Path to directory containing custom templates
statusCodes --status-codes -S operation.responses false comma separated list of status codes to explicity generate tests for


To test this module simply use the npm script

npm test


If you have a question or a topic you'd like to discuss, please feel free to open a discussion on our Google Group oatts-users.


Contributors are welcome! Please see


Copyright 2018, Google Inc.


See LICENSE file.