silk 
Markdown based document-driven web API testing.
- Write nice looking Markdown documentation (like this), and then run it using the silk command
- Simple and robust Markdown API
- Comes with real examples that you can copy (that are also part of the test suite for the project)
- 10% discount on LightPaper markdown editor app for Silk users: use
SILKTESTcode.
Learn more
(VIDEO) Watch the talk about Silk (with slides) or read about Silk in this blog post.
Markdown API
Tests are made up of documents written in Markdown.
# Group- Top level headings represent groups of requests## GET /path- Second level headings represent a request- Code blocks with three back tics represent bodies
* Field: value- Lists describe headers and assertions* ?param=value- Request parameters---seperators break requests from responses- Comments (starting with
//) allow you to capture variables - Plain text is ignored to allow you to add documentation
- Inline back tics are ignored and are available for formatting
Document structure
A document is made up of:
- A request
---seperator- Assertions
Requests
A request starts with ## and must have an HTTP method, and a path:
## METHOD /path
Examples include:
## GET /people
## POST /people/1/comments
## DELETE /people/1/comments/2
Request body (optional)
To specify a request body (for example for POST requests) use a codeblock using backtics (```):
```
{"name": "Silk", "release_year": 2016}
```
Request headers (optional)
You may specify request headers using lists (prefixed with *):
* Content-Type: "application/json"
* X-Custom-Header: "123"
Request parameters (optional)
Adding parameters to the path (like GET /path?q=something) can be tricky, especially when you consider escaping etc. To address this, Silk supports parameters like lists:
* ?param=value
The parameters will be correctly added to the URL path before the request is made.
Cookies
Setting cookies on a request can be done using the HTTP header pattern:
* Cookie: "key=value"
- See asserting cookies.
Assertions
Following the --- separator, you can specify assertions about the response. At a minimum, it is recommended that you assert the status code to ensure the request succeeded:
* Status: 200
You may also specify response headers in the same format as request headers:
* Content-Type: "application/json"
* X-MyServer-Version: "v1.0"
If any of the headers do not match, the test will fail.
Capturing data
Silk allows you to capture values at the point of asserting them and reuse them in future requests and assertions. To capture a value, include a comment on the line that mentions a {placeholder}:
* Data.UserID: /.*/ // The user's unique {id}.
The value from UserID (e.g. 123) will be stored in a variable called id, and you can refer to it later:
## GET /users/{id}
The above would be a request to GET /users/123.
- Captured values are only available when assertions are successful
Environment variables
You can access environment variables inside Silk tests using the {$NAME} format, where NAME is the environment name.
Asserting cookies
To assert that a cookie is present in a response, make a regex assertion against the Set-Cookie HTTP header:
* Set-Cookie: /key=value/
- All cookie strings are present in a single
Set-Cookieseperated by a pipe character.
Validating data
You can optionally include a verbatim body using code blocks surrounded by three back tics. If the response body does not exactly match, the test will fail:
```
Hello world!
```
You can flag expected response bodies as json directly after the three back tics.
This will assert that the actual response contains the same value for each expected key (recursively)
allowing for differences in whitespace and ordering as well as being lenient towards additional (unexpected) keys in the response.
```json
{
"id": 1,
"release_year": 2016,
"name": "Silk"
}
```
You can use the flag json(strict) to enforce that no additional fields may be present while still allowing for differences in whitespace and key order.
You may also make any number of regex assertions against the body using the Body object:
* Body: /Hello world/
* Body: /This should be found too/
* Body: /and this/
Alternatively, you can specify a list (using *) of data fields to assert accessible via the Data object:
* Status: 201
* Content-Type: "application/json"
* Data.name: "Silk"
* Data.release_year: 2016
* Data.tags[0]: "testing"
* Data.tags[1]: "markdown"
* Data[0].name: "Mat"
* Data[1].name: "David"
- NOTE: Currenly this feature is only supported for JSON APIs.
Regex
Values may be regex, if they begin and end with a forward slash: /. The assertion will pass if the value (after being turned into a string) matches the regex.
* Status: /^2.{2}$/
* Content-Type: /application/json/
The above will assert that:
- The status looks like
2xx, and - The
Content-Typecontainsapplication/json
Command line
The silk command runs tests against an HTTP endpoint.
Usage:
silk -silk.url="{endpoint}" {testfiles...}
{endpoint}the endpoint URL (e.g.http://localhost:8080){testfiles}list of test files (e.g../testfiles/one.silk.md ./testfiles/two.silk.md)
Notes:
- Omit trailing slash from
endpoint {testfiles}can include a pattern (e.g./path/*.silk.md) as this is expended by most terminals to a list of matching files
Golang
Silk is written in Go and integrates seamlessly into existing testing tools and frameworks. Import the runner package and use RunGlob to match many test files:
package project_test
import (
"testing"
"github.com/matryer/silk/runner"
)
func TestAPIEndpoint(t *testing.T) {
// start a server
s := httptest.NewServer(yourHandler)
defer s.Close()
// run all test files
runner.New(t, s.URL).RunGlob(filepath.Glob("../testfiles/failure/*.silk.md"))
}
Credit
- Special thanks to @dahernan for his contributions and criticisms of Silk
- Silk logo by Chris Ryer