The document discusses the use of testing libraries for REST APIs, highlighting the importance and architecture of REST, as well as the role of the OpenAPI Initiative in standardizing API interfaces. It details tools and code examples for mocking servers and client behavior using WireMock and Rest Assured. Additionally, it presents testing techniques and methodologies involving Spock and various other libraries to enhance productivity in API development and testing.

1. TESTING LIBRARIES
FOR FUN & PROFIT
BEWARE: INCREASED PRODUCTIVITY AHEAD@IXCHELRUIZ — PRINCIPAL CONSULTANT
TRIVADIS AG

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AIM
Rest APIs
Fake Servers
Fake Clients
Parameterized Tests
Spy, Mock, Stub

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Open Source

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REST API

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WHAT? WHY? WHO? WHEN?
REpresentational State Transfer.
“Architectural style for distributed hypermedia
systems, as it has been developed to represent the
model for how the modern Web should work. REST
provides a set of architectural constraints that,
when applied as a whole, emphasizes scalability of
component interactions, generality of interfaces,
independent deployment of components, and
intermediary components to reduce interaction
latency, enforce security, and encapsulate legacy
systems”

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WHAT? WHY? WHO? WHEN?
REpresentational State Transfer.
“Architectural style for distributed hypermedia
systems, as it has been developed to represent the
model for how the modern Web should work. REST
provides a set of architectural constraints that,
when applied as a whole, emphasizes scalability of
component interactions, generality of interfaces,
independent deployment of components, and
intermediary components to reduce interaction
latency, enforce security, and encapsulate legacy
systems”

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WHAT? WHY? WHO? WHEN?
REpresentational State Transfer.
“Architectural style for distributed hypermedia
systems, as it has been developed to represent the
model for how the modern Web should work. REST
provides a set of architectural constraints that,
when applied as a whole, emphasizes scalability of
component interactions, generality of interfaces,
independent deployment of components, and
intermediary components to reduce interaction
latency, enforce security, and encapsulate legacy
systems”
— Roy Thomas Fielding
https://www.ics.uci.edu/~fielding/pubs/dissertation/web_arch_domain.htm

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WHAT? WHO? WHY? WHEN?
REpresentational State Transfer.
“Architectural style for distributed hypermedia
systems, as it has been developed to represent the
model for how the modern Web should work. REST
provides a set of architectural constraints that,
when applied as a whole, emphasizes scalability of
component interactions, generality of interfaces,
independent deployment of components, and
intermediary components to reduce interaction
latency, enforce security, and encapsulate legacy
systems”
— Roy Thomas Fielding (2000)
https://www.ics.uci.edu/~fielding/pubs/dissertation/web_arch_domain.htm

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STATE OF AFFAIRS
Heterogeneous collection of
terminals, workstations, servers
and supercomputers.

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STATE OF AFFAIRS
Heterogeneous collection of
terminals, workstations, servers
and supercomputers.

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STATE OF AFFAIRS
Evolution of REST APIs
(Model, Documentation,
Implementation)

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OPEN API 3.0OAI/OPENAPI-SPECIFICATION

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WHAT? WHY? WHO? WHEN?
“Define a standard, language-agnostic interface to
REST APIs which allows both humans and
computers to discover and understand the
capabilities of the service without access to source
code, documentation, or through network traffic
inspection. When properly defined via OpenAPI, a
consumer can understand and interact with the
remote service with a minimal amount of
implementation logic.”

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WHAT? WHY? WHO? WHEN?
“Define a standard, language-agnostic interface to
REST APIs which allows both humans and
computers to discover and understand the
capabilities of the service without access to source
code, documentation, or through network traffic
inspection. When properly defined via OpenAPI, a
consumer can understand and interact with the
remote service with a minimal amount of
implementation logic.”
#vendorNeutral #portable #open #specification #technical
#metadata

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WHAT? WHY? WHO? WHEN?
“Define a standard, language-agnostic interface to
REST APIs which allows both humans and
computers to discover and understand the
capabilities of the service without access to source
code, documentation, or through network traffic
inspection. When properly defined via OpenAPI, a
consumer can understand and interact with the
remote service with a minimal amount of
implementation logic.”
#vendorNeutral #portable #open #specification #technical
#metadata
— OpenApi Initiative

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WHAT? WHO? WHY? WHEN?
“Define a standard, language-agnostic interface to
REST APIs which allows both humans and
computers to discover and understand the
capabilities of the service without access to source
code, documentation, or through network traffic
inspection. When properly defined via OpenAPI, a
consumer can understand and interact with the
remote service with a minimal amount of
implementation logic.”
#vendorNeutral #portable #open #specification #technical
#metadata
— OpenApi Initiative (Jul 26, 2017)

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OPEN API INITIATIVE

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WHAT? WHY? WHO? WHEN?
“The OpenAPI Initiative (OAI) was created by a
consortium of forward-looking industry experts
who recognize the immense value of standardizing
on how REST APIs are described. Provides an open
source, technical community, within which industry
participants may easily contribute to building a
vendor-neutral, portable and open specification for
providing technical metadata for REST APIs. The
OAI is a collaborative project under the guidance of
the The Linux Foundation”

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WHAT? WHY? WHO? WHEN?
“The OpenAPI Initiative (OAI) was created by a
consortium of forward-looking industry experts
who recognize the immense value of standardizing
on how REST APIs are described. Provides an open
source, technical community, within which
industry participants may easily contribute to
building a vendor-neutral, portable and open
specification for providing technical metadata for
REST APIs. The OAI is a collaborative project under
the guidance of the The Linux Foundation”

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WHAT? WHY? WHO? WHEN?

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WHAT? WHY? WHO? WHEN?
2015

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Tools that support OpenApi 3.0
http://openapi.tools

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PROFIT
OPEN API
INITIATIVE & SPEC

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OPEN API 3.0
“Define a standard, language-agnostic interface to
REST APIs which allows both humans and
computers to discover and understand the
capabilities of the service without access to source
code, documentation, or through network traffic
inspection. When properly defined via OpenAPI,
a consumer can understand and interact with the
remote service with a minimal amount of
implementation logic.”
— Open API Initiative

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OPEN API 3.0
“Define a standard, language-agnostic interface to
REST APIs which allows both humans and
computers to discover and understand the
capabilities of the service without access to source
code, documentation, or through network traffic
inspection. When properly defined via OpenAPI,
a consumer can understand and interact with the
remote service with a minimal amount of
implementation logic.”
— Open API Initiative

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REST API
SPEC

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DEMO

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https://editor.swagger.io

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SWAGGER
EDITOR

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https://github.com/swagger-api/swagger-editor

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SWAGGER
CODEGEN

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https://github.com/swagger-api/swagger-codegen

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https://github.com/swagger-api/swagger-codegen/wiki/Server-stub-generator-HOWTO

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WIREMOCK

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http://wiremock.org

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DEMO

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Standalone

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Configure ports
$ java -jar wiremock-standalone-2.19.0.jar -- port 9090
Record & Map
$ java -jar wiremock-standalone-2.19.0.jar --proxy-all http://
wiremock.org —record-mappings
Review the mappings
http://localhost:8080/__admin/
Replay
$ java -jar wiremock-standalone-2.19.0.jar

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Adding mappings (text/plain)
$ curl --verbose --data '{
"request": { "url": "/get/this", "method": "GET" },
"response": {
"status": 200, "body": "Here it is!n",
"headers": {"Content-Type": "text/plain"}
}}' http://localhost:8080/__admin/mappings/new
Test the new mapping
$ curl http://localhost:8080/get/this

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Adding mappings (json)
$ curl --verbose --data '{
"request": { "url": "/get/json", "method": "GET" },
"response": {
"status": 200,
"jsonBody": {"unconferences":["jCrete","jAlba","jTaco"]},
"headers": {"Content-Type": "application/json"}
}}' http://localhost:8080/__admin/mappings/new
Test the new mapping
$ curl http://localhost:8080/get/json

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Adding patterns in URLs
$ curl --verbose --data '{
"request": {
"urlPathPattern": "/get/([a-z]*)/test", "method": "GET" },
"response": {
"status": 200,
"body": "Here it is with pattern"
}}' http://localhost:8080/__admin/mappings/new
Test the new mapping
$ curl http://localhost:8080/get/whatever/test

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Using patterns is the body
$ curl --verbose --data '{
"request": { "method": "POST", "url": "/post/bodyPattern",
"bodyPatterns" : [ {
"equalToJson" : { "total_results": 4 } }] },
"response": {
"status": 200, "body": "The body pattern was matched"
}}' http://localhost:8080/__admin/mappings/new
Test the new mapping
$ curl --verbose --data '{
"total_results":4}'
http://localhost:8080/post/bodyPattern

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http://wiremock.org/docs/request-matching/

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Delaying responses
$curl --verbose --data '{
"request": { "method": "GET", "url": "/get/delayed" },
"response": {
"status": 200,
"fixedDelayMilliseconds": 2000
}}' http://localhost:8080/__admin/mappings/new
Test the new mapping
$ curl http://localhost:8080/get/delayed

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Simulating Fault
$curl --verbose --data '{
"request": {
"method": "GET", "url": "/get/fault"},
"response": {
"fault": "MALFORMED_RESPONSE_CHUNK"
}}' http://localhost:8080/__admin/mappings/new
Test the new mapping
$ curl http://localhost:8080/get/fault

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Verifying number of requests
$ curl -X POST --header 'Content-Type: application/json'
--header 'Accept: application/json'
-d '{"url":"/get/delayed"}' 'http://localhost:8080/__admin/
requests/count'
Admin reference
http://localhost:8080/__admin/docs/
Reset
http://localhost:8080/__admin/reset/

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https://chrome.google.com/webstore/detail/wiremock-extension/ikiaofdpbmofgmlhajfnhdjelkleljbl

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REST
ASSURE

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http://rest-assured.io

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EXAMPLES

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import static io.restassured.RestAssured.given;
import static io.restassured.RestAssured.get;
import static java.util.Arrays.asList;
import static org.hamcrest.Matchers.equalTo;
import org.junit.Test;
@Test
public void initial_data_is_loaded() {
given().
port(4567).
when().
get("/todos").
then().
body("todos.description", equalTo(asList(“Add Javadoc")));
}
@Test
public void formParamAreTreatedAsQueryParamsForGetRequests(){
given().
formParam("firstName", "John").
formParam("lastName", "Doe").
when().
get("/greet").
then().
body("greeting", equalTo("Greetings John Doe"));
}

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import static io.restassured.RestAssured.given;
import static io.restassured.RestAssured.expect;
import static org.hamcrest.Matchers.equalTo;
import org.junit.Test;
@Test
public void newSyntaxWithCorrectStatusLineUsingStringMatching() {
expect().
statusLine("HTTP/1.1 200 OK").and().body("lotto.lottoId", equalTo(5)).
when().
get("/lotto");
}
@Test
public void requestSpecificationAllowsSpecifyingCookie() {
given().
cookie("username", “John”).then().
expect().
body(equalTo("username")).when().get("/cookie");
}
@Test
public void given_when_then_using_i18n_works() {
get(“/i18n").
then().
assertThat().body("ön", equalTo("Är ån"));
}

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SPOCK

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http://spockframework.org

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EXAMPLES

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@spock.lang.Unroll
class SampleControllerSpec extends spock.lang.Specification {
def "Invoke say hello with #input results in #output"() {
given:
SampleController controller = new SampleController()
controller.model = new SampleModel()
controller.service = Mock(SampleService) {
sayHello(input) >> output
}
when:
controller.model.input = input controller.sayHello()
then:
controller.model.output == output
where:
input << ['', 'Test']
output << ['Howdy, stranger!', 'Hello Test']
}
}

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@spock.lang.Unroll
class SampleControllerSpec extends spock.lang.Specification {
def "Invoke say hello with #input results in #output"() {
given:
SampleController controller = new SampleController()
controller.model = new SampleModel()
controller.service = Mock(SampleService) {
sayHello(input) >> output
}
when:
controller.model.input = input
controller.sayHello()
then:
controller.model.output == output
where:
input | output
'' | 'Test'
'Howdy, stranger!' | 'Hello Test'
}
}

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THANK YOU
FEEDBACK?