Peter Thomas on his latest open source project, KarateDSL for Complex Web-Service API Testing. Presented at the #GIDS17 conference, Bangalore.

1. Peter Thomas
Architect | Intuit
@ptrthomas | @KarateDSL
Karate for Complex Web-
Service API Testing

2. 2
What you can expect from this session
I want to test web-services and
currently use Java
I want to test web-services but
don’t know Java
I develop web-services
I am part of a team delivering or
maintaining web-services
Karate is easier and more
effective than Java
Karate is not-Java and
scripts are plain-text
Karate can be used for
TDD of web-services
Karate increases velocity,
and fits into your existing
QA / CI / CD

3. Karate
github.com/intuit/karate
Intuit Open Source
Released 09-Feb-2017
A DSL for writing web-service acceptance tests
Built on Cucumber | BDD syntax

4. 4
Karate – the story so far
Released 09-Feb-2017
170 ‘stars’ in 2 months

5. 5
Many teams use Java for writing HTTP-API
regression tests.
Java is not the best language to manipulate
JSON / XML.
Consequences:
• Over-dependence on Java objects for
building and validating data-payloads
• Object-equality checks done by hand,
effort-intensive
• So tests end-up taking “short-cuts”, and
don’t validate the full response, coverage
& quality suffers
• Proliferation of helper methods, code bloat
& in-house layers
• Result: poor Dev Productivity &
Maintainability
Current State of Web-API Testing
• DSL laser-focused on HTTP
• JSON and XML are “first-class”
citizens of the syntax
• Compare deeply-nested payloads in
a single step
• 3:1 Reduction in Lines of Code
• Tests are super-readable and concise
• Testing is Easier & actually Fun
Karate’s Solve

6. 6
Scenario: create and retrieve a cat
Given url 'http://myhost.com/v1/cats'
And request { name: 'Billie' }
When method post
Then status 201
And match response == { id: '#notnull', name: 'Billie' }
Given path response.id
When method get
Then status 200
Hello World
Intuitive DSL for
HTTP
Payload
assertion in
one line
Second HTTP
call using
response data
JSON is ‘native’
to the syntax

7. 7
Java
vs
JSON

8. 8
Validation examples: JsonPath & RegEx
Type Directive
Ignore / exists #ignore | #null | #notnull
Primitive Type #boolean | #number | #string
Complex Type #array | #object
Special #uuid
RegEx #regex <regex string>
Predicate #? <expression>

9. 9
JSON ‘templating’
Type Directive
Replace #(<expression>)

10. 10
XML and XPath

11. 11
Comparison with REST-assured
http://tinyurl.com/karatera
REST-assured Karate
Plain Text ❌ (needs compilation) ✅
Parallel Execution ? (partial) ✅
Data Driven Testing ❌ (needs TestNG etc.) ✅ (built-in)
Environment Switching ❌ ✅ (built-in)
Match full payload in one step ❌ ✅
Update JSON payload / object ❌ ✅
@Test public void
lotto_resource_returns_200_with_expected_id_and_winners() {
when().
get("/lotto/{id}", 5).
then().
statusCode(200).
body("lotto.lottoId", equalTo(5),
"lotto.winners.winnerId", containsOnly(23, 54));
Scenario: lotto resource returns 200 with expected id and winners
Given path ‘lotto’, 5
When method get
Then status 200
And match $.lotto.lottoId == 5
And match $.lotto.winners[*].winnerId contains only [23, 54]
given().
param("key1", "value1").
param("key2", "value2").
when().
get("/somewhere").
then().
body(containsString("OK"));
Given param key1 = ‘value1’
And param key2 = ‘value2’
And path ‘somewhere’
When method get
Then response contains ‘OK’

12. 12

13. 13
Components
Karate DSL interpreter
(Cucumber “Step Definitions”)
HTTP Client
Abstraction
JSON XML
JS
Engine
(Nashorn)
Karate ScriptJUnit /
Test NG
(Runner)
Java8JRE
HTTP/S calls
Cucumber-
JVM
Data Functions
match, get, set
Reports
Apache Jersey

14. 14
• Built on Cucumber, BDD syntax
• Scripts are plain-text, no compilation or IDE required
• REST as well as SOAP support
• Assert, manipulate, compare and re-use JSON / XML
• User defined functions (Java or JavaScript)
• Configuration switching (e.g. dev | e2e | pre-prod)
• Simple ‘plug and play’ HTTP Header & Auth management
• Comprehensive HTTP support: SSL, Proxy, File-Upload
• JUnit XML reports compatible with all CI tools
• Speed - Parallel Execution of Tests
Karate Features
BDD
Full HTTP
CI / CD
Ready

15. Demos

16. Q & A
https://github.com/intuit/karate
@ptrthomas | @KarateDSL

17. 17
The “missing” Cucumber Features that Karate adds
Capability Cucumber Karate
Step Definitions built-in, no Java code needed ❌ ✅
Re-Use Feature files from other Features ❌ ✅
Dynamic Data-Driven Testing ❌ ✅
Parallel Test Execution and Reporting ❌ ✅
Option to run routines only once per Feature ❌ ✅

18. 18
CI Report
(Jenkins)