Advanced HTTP Mocking with WireMock

Video Recording: https://youtu.be/x3MvZ8DFrpE

Create HTTP mocks with WireMock’s REST API from any language for deterministic testing and development. Don’t have mocks yet? No worries. You can record live traffic with WireMock that can be played back. Testing apps that rely on APIs can be painful, flaky and complicated because more than likely, the APIs you rely on are out of your control. It’s time to take control back.

During this talk, you’ll learn how to do the following:

* Record and playback network traffic.

* Programmatically setup mocks via the REST API with cURL, Node.js and Java.

* Simulate error scenarios & latency.

* Verify HTTP calls were made the expected number of times and with expected content.

* Simulate stateful behavior using “scenario” mappings (same endpoint, different results).

Bonuses:

* WireMock is FREE and OPEN SOURCE!

* All of WireMock’s features are accessible via its REST (JSON) interface and its Java API.

* There is a WireMockRule for Java JUnit tests.

* WireMock can run as an embedded HTTP server on an Android device. (with a few config tweaks)

Transcript

1. ADVANCED HTTP MOCKING
   WITH WIREMOCK
   Sam Edwards - @HandstandSam
   

   View Slide

2. @HandstandSam
   #DevFestDC
   Why Mock HTTP?
   

   View Slide

3. @HandstandSam
   #DevFestDC
   Why Mock HTTP?
   ● Speed
   

   View Slide

4. @HandstandSam
   #DevFestDC
   Why Mock HTTP?
   ● Speed
   ● Avoid Rate Limits
   

   View Slide

5. @HandstandSam
   #DevFestDC
   Why Mock HTTP?
   ● Speed
   ● Avoid Rate Limits
   ● Avoid Modifying State
   

   View Slide

6. @HandstandSam
   #DevFestDC
   Why Mock HTTP?
   ● Speed
   ● Avoid Rate Limits
   ● Avoid Modifying State
   ● Edge Cases
   

   View Slide

7. @HandstandSam
   #DevFestDC
   Why Mock HTTP?
   ● Speed
   ● Avoid Rate Limits
   ● Avoid Modifying State
   ● Edge Cases
   ● Error Scenarios
   

   View Slide

8. @HandstandSam
   #DevFestDC
   Why Mock HTTP?
   ● Speed
   ● Avoid Rate Limits
   ● Avoid Modifying State
   ● Edge Cases
   ● Error Scenarios
   ● Deterministic
   

   View Slide

9. @HandstandSam
   #DevFestDC
   Why Mock HTTP?
   ● Speed
   ● Avoid Rate Limits
   ● Avoid Modifying State
   ● Edge Cases
   ● Error Scenarios
   ● Deterministic
   ● Testing and TDD
   

   View Slide

10. @HandstandSam
    #DevFestDC
    Mock What and Where?
    

    View Slide

11. @HandstandSam
    #DevFestDC
    What and Where to Mock?
    Client (Web/Mobile) HTTP Service
    

    View Slide

12. @HandstandSam
    #DevFestDC
    What and Where to Mock?
    Client (Web/Mobile)
    

    View Slide

13. @HandstandSam
    #DevFestDC
    What and Where to Mock?
    Client (Web/Mobile) HTTP Service
    Backend Services
    

    View Slide

14. @HandstandSam
    #DevFestDC
    What and Where to Mock?
    Client (Web/Mobile) HTTP Service
    

    View Slide

15. @HandstandSam
    #DevFestDC
    What and Where to Mock?
    Client (Web/Mobile) HTTP Service
    Backend Services
    3rd Party Services
    

    View Slide

16. @HandstandSam
    #DevFestDC
    What and Where to Mock?
    Client (Web/Mobile) HTTP Service
    Backend Services
    

    View Slide

17. @HandstandSam
    #DevFestDC
    What is WireMock?
    

    View Slide

18. @HandstandSam
    #DevFestDC
    Open Source, Started in 2011 by Tom Akehurst
    

    View Slide

19. @HandstandSam
    #DevFestDC
    Running WireMock
    

    View Slide

20. @HandstandSam
    #DevFestDC
    Open Source Tool for Mocking HTTP Akehurst.
    

    View Slide

21. @HandstandSam
    #DevFestDC
    Running WireMock
    ● Download Standalone JAR from Maven Central
    ● java -jar wiremock-standalone-2.6.0.jar
    ● http://localhost:8080/__admin/
    ● --port
    ● --https-port
    

    View Slide

22. @HandstandSam
    #DevFestDC
    Proxying, Recording and
    Playback
    

    View Slide

23. @HandstandSam
    #DevFestDC
    --proxy-all
    ● --proxy-all http://wiremock.org
    Client (Web/Mobile) http://wiremock.org
    

    View Slide

24. @HandstandSam
    #DevFestDC
    --verbose
    ● See all traffic going through WireMock.
    

    View Slide

25. @HandstandSam
    #DevFestDC
    --record-mappings
    ● java -jar wiremock-standalone-2.6.0.jar --proxy-all http://wiremock.org
    --record-mappings
    ● Record all traffic to file-based WireMock mappings.
    Client (Web/Mobile) http://wiremock.org
    /__files /mappings
    

    View Slide

26. @HandstandSam
    #DevFestDC
    Playback
    ● java -jar wiremock-standalone-2.6.0.jar
    ● Playback traffic to file-based WireMock mappings.
    Client (Web/Mobile)
    /__files /mappings
    

    View Slide

27. @HandstandSam
    #DevFestDC
    ● Before & After
    ● curl http://localhost:8080
    Manipulating Files
    Client (Web/Mobile)
    /__files /mappings
    

    View Slide

28. @HandstandSam
    #DevFestDC
    ● http://localhost:8080/__admin/
    Viewing Mappings
    /__files /mappings
    

    View Slide

29. @HandstandSam
    #DevFestDC
    Language Agnostic Stubbing
    via REST API
    

    View Slide

30. @HandstandSam
    #DevFestDC
    Stubbing via REST API - String Body
    curl --verbose \
    -X POST \
    --data '{
    "request": {
    "method": "GET",
    "urlPath": "/hello"
    },
    "response": {
    "status": 200,
    "body": "Hello world!",
    "headers": {
    "Content-Type": "text/plain"
    }
    }
    }' \
    'http://localhost:8080/__admin/mappings'
    

    View Slide

31. @HandstandSam
    #DevFestDC
    Stubbing via REST API - JSON Response
    curl --verbose \
    -X POST \
    --data '{
    "request": {
    "method": "GET",
    "url": "/json"
    },
    "response": {
    "status": 200,
    "jsonBody": {
    "numbers": [1, 2, 3]
    },
    "headers": {
    "Content-Type": "application/json"
    }
    }
    }' \
    'http://localhost:8080/__admin/mappings'
    

    View Slide

32. @HandstandSam
    #DevFestDC
    Stubbing via REST API - Binary Response
    curl --verbose \
    -X POST \
    --data '{
    "request": {
    "method": "GET",
    "url": "/binary"
    },
    "response": {
    "status": 200,
    "base64Body" : "WUVTIElOREVFRCE="
    }
    }' \
    'http://localhost:8080/__admin/mappings'
    

    View Slide

33. @HandstandSam
    #DevFestDC
    Complex Stubbing
    

    View Slide

34. @HandstandSam
    #DevFestDC
    HTTP Method Stubbing
    ● ANY
    ● GET
    ● POST
    ● PUT
    ● DELETE
    ● etc....
    

    View Slide

35. @HandstandSam
    #DevFestDC
    URL Pattern Stub
    curl --verbose \
    -X POST \
    --data '{
    "request": {
    "method": "GET",
    "urlPathPattern": "/.*/profile$"
    },
    "response": {
    "status": 200,
    "body": "User profile goes here.",
    "headers": {
    "Content-Type": "text/plain"
    }
    }
    }' \
    'http://localhost:8080/__admin/mappings'
    

    View Slide

36. @HandstandSam
    #DevFestDC
    Query Parameter Stub
    curl --data '{
    "request": {
    "method": "GET",
    "urlPath": "/query",
    "queryParameters":{
    "q": {
    "equalTo": "wiremock"
    }
    }
    },
    "response": {
    "status": 200,
    "body": "It looks like you were searching for WireMock :-) Try href=\"http://wiremock.org\">http://wiremock.org"
    }
    }' \
    'http://localhost:8080/__admin/mappings'
    

    View Slide

37. @HandstandSam
    #DevFestDC
    Header Matching Stub
    curl --verbose \
    -X POST \
    --data '{
    "request": {
    "method": "GET",
    "urlPath": "/endpoint",
    "headers" : {
    "Accept" : {
    "contains" : "application/json;v=2"
    }
    }
    },
    "response": {
    "status": 200,
    "jsonBody": {
    "version": 2
    },
    "headers": {
    "Content-Type": "application/json"
    }
    }
    }' \
    'http://localhost:8080/__admin/mappings'
    

    View Slide

38. @HandstandSam
    #DevFestDC
    Header Matching - Miss
    curl --header 'Accept: application/json;v=1' \
    'http://localhost:8080/endpoint'
    

    View Slide

39. @HandstandSam
    #DevFestDC
    Header Matching - Match
    curl --header 'Accept: application/json;v=2' \
    'http://localhost:8080/endpoint'
    

    View Slide

40. @HandstandSam
    #DevFestDC
    Request Body Matching
    curl --verbose \
    -X POST \
    --data '{
    "request": {
    "method": "POST",
    "urlPath": "/worldseries",
    "bodyPatterns" : [
    {
    "contains" : "Orioles"
    }
    ]
    },
    "response": {
    "status": 200,
    "body": "Orioles win the 2017 World Series!!!"
    }
    }' \
    'http://localhost:8080/__admin/mappings'
    

    View Slide

41. @HandstandSam
    #DevFestDC
    Request Body Matching Requests
    curl --data '{ "team": "Orioles", "score": 10 }' \
    'http://localhost:8080/worldseries'
    

    View Slide

42. @HandstandSam
    #DevFestDC
    JSON Body Matching Stub
    curl --verbose \
    -X POST \
    --data '{
    "request": {
    "method": "POST",
    "urlPath": "/score",
    "bodyPatterns" : [
    {
    "equalToJson" : "{ \"score\": 10, \"team\": \"Orioles\" }"
    }
    ]
    },
    "response": {
    "status": 200,
    "body": "Orioles win the 2018 World Series!!!"
    }
    }' \
    'http://localhost:8080/__admin/mappings'
    

    View Slide

43. @HandstandSam
    #DevFestDC
    JSON Body Matching Requests
    curl --data '{ "team": "Orioles", "score": 10 }' \
    'http://localhost:8080/score'
    curl --data '{ "score": 10, "team": "Orioles" }' \
    'http://localhost:8080/score'
    curl --data '{ "score": 1, "team": "Red Sox" }' \
    'http://localhost:8080/score'
    

    View Slide

44. @HandstandSam
    #DevFestDC
    Stubbing via REST API - “Catch All” for Unmatched
    curl --verbose \
    -X POST \
    --data '{
    "priority":10,
    "request": {
    "method": "ANY",
    "urlPattern": ".*"
    },
    "response": {
    "status": 404,
    "jsonBody": {"status":"Error","message":"Endpoint not found"},
    "headers": {
    "Content-Type": "application/json"
    }
    }
    }' \
    'http://localhost:8080/__admin/mappings'
    

    View Slide

45. @HandstandSam
    #DevFestDC
    Obtaining a Stub Mapping ID
    Response from WireMock:
    {
    "id" : "4d37cd0d-53dc-46d6-809d-9de83894e167",
    "request" : {
    "url" : "/hello",
    "method" : "GET"
    },
    "response" : {
    "status" : 200,
    "body" : "Hello world!",
    "headers" : {
    "Content-Type" : "text/plain"
    }
    },
    "uuid" : "4d37cd0d-53dc-46d6-809d-9de83894e167"
    }
    

    View Slide

46. @HandstandSam
    #DevFestDC
    Editing Stubs via REST API
    curl --verbose \
    -X PUT \
    --data '{
    "request": {
    "method": "GET",
    "url": "/hello"
    },
    "response": {
    "status": 200,
    "body": "Hello world!",
    "headers": {
    "Content-Type": "text/plain"
    }
    }
    }' \
    'http://localhost:8080/__admin/mappings/4d37cd0d-53dc-46d6-809d-9de83894e167'
    

    View Slide

47. @HandstandSam
    #DevFestDC
    Deleting Stubs via REST API
    curl --verbose \
    -X DELETE \
    'http://localhost:8080/__admin/mappings/4d37cd0d-53dc-46d6-809d-9de83894e167'
    

    View Slide

48. @HandstandSam
    #DevFestDC
    https://chrome.google.com/webstore/detail/wiremock-extension/ikiaofdpbmofgmlhajfnhdjelkleljbl
    

    View Slide

49. @HandstandSam
    #DevFestDC
    Resetting WireMock Server
    curl --verbose \
    -X POST \
    'http://localhost:8080/__admin/reset'
    

    View Slide

50. @HandstandSam
    #DevFestDC
    Simulating Errors and Latency
    

    View Slide

51. @HandstandSam
    #DevFestDC
    Pre-Defined Fault Types
    ● EMPTY_RESPONSE
    ○ Return a completely empty response.
    ● MALFORMED_RESPONSE_CHUNK
    ○ Send an OK status header, then garbage, then close the connection.
    ● RANDOM_DATA_THEN_CLOSE
    ○ Send garbage then close the connection.
    

    View Slide

52. @HandstandSam
    #DevFestDC
    Simulating Faults
    curl --verbose \
    -X POST \
    --data '{
    "request": {
    "method": "GET",
    "url": "/fault"
    },
    "response": {
    "fault": "MALFORMED_RESPONSE_CHUNK"
    }
    }' \
    'http://localhost:8080/__admin/mappings'
    

    View Slide

53. @HandstandSam
    #DevFestDC
    Stub Specific Fixed Delay
    curl --verbose \
    -X POST \
    --data '{
    "request": {
    "method": "GET",
    "url": "/delayed"
    },
    "response": {
    "status": 200,
    "body": "Better late than never!",
    "fixedDelayMilliseconds": 2000
    }
    }' \
    'http://localhost:8080/__admin/mappings'
    

    View Slide

54. @HandstandSam
    #DevFestDC
    Global Random Delay (Can be set specifically as well)
    curl --verbose \
    -X POST \
    --data '{
    "delayDistribution": {
    "type": "uniform",
    "lower": 0,
    "upper": 5000
    }
    }' \
    'http://localhost:8080/__admin/settings'
    

    View Slide

55. @HandstandSam
    #DevFestDC
    Verifying Networking Calls
    

    View Slide

56. @HandstandSam
    #DevFestDC
    Verifying Network Calls
    curl --verbose \
    -X POST \
    --data '{
    "method": "GET",
    "url": "/delayed"
    }' \
    'http://localhost:8080/__admin/requests/count'
    

    View Slide

57. @HandstandSam
    #DevFestDC
    Full Journal of Network Requests
    curl --verbose \
    -X GET \
    'http://localhost:8080/__admin/requests'
    

    View Slide

58. @HandstandSam
    #DevFestDC
    Stateful Behavior with
    Scenarios
    

    View Slide

59. @HandstandSam
    #DevFestDC
    Stateful Behavior with Scenarios
    Grocery List Scenario
    GET /items
    “Started”
    1. Bread
    GET /items
    “One Item”
    1. Bread
    2. Milk
    GET /items
    “Two Items”
    

    View Slide

60. @HandstandSam
    #DevFestDC
    Grocery List Scenario - No Items (“Started”)
    curl --verbose \
    -X POST \
    --data '{
    "scenarioName": "Grocery List",
    "requiredScenarioState": "Started",
    "newScenarioState": "One Item",
    "request": {
    "method": "GET",
    "url": "/items"
    },
    "response": {
    "status": 200,
    "jsonBody" : []
    }
    }' \
    'http://localhost:8080/__admin/mappings'
    

    View Slide

61. @HandstandSam
    #DevFestDC
    Grocery List Scenario - No Items (“One Item”)
    curl --verbose \
    -X POST \
    --data '{
    "scenarioName": "Grocery List",
    "requiredScenarioState": "One Item",
    "newScenarioState": "Two Items",
    "request": {
    "method": "GET",
    "url": "/items"
    },
    "response": {
    "status": 200,
    "jsonBody" : ["Milk"]
    }
    }' \
    'http://localhost:8080/__admin/mappings'
    

    View Slide

62. @HandstandSam
    #DevFestDC
    Grocery List Scenario - No Items (“One Item”)
    curl --verbose \
    -X POST \
    --data '{
    "scenarioName": "Grocery List",
    "requiredScenarioState": "Two Items",
    "newScenarioState": "Started",
    "request": {
    "method": "GET",
    "url": "/items"
    },
    "response": {
    "status": 200,
    "jsonBody" : ["Milk", "Bread"]
    }
    }' \
    'http://localhost:8080/__admin/mappings'
    

    View Slide

63. @HandstandSam
    #DevFestDC
    Resetting WireMock Scenarios
    curl --verbose \
    -X POST \
    'http://localhost:8080/__admin/scenarios/reset'
    

    View Slide

64. @HandstandSam
    #DevFestDC
    What Kind of Stubbing
    Should I Use?
    File Based vs. Programmatic
    

    View Slide

65. @HandstandSam
    #DevFestDC
    File-Based Stubbing
    Great for:
    ● Recording
    ● Understandability
    ● Sharing
    Not the best for:
    ● Advanced usage
    ● Maintainability
    

    View Slide

66. @HandstandSam
    #DevFestDC
    Programmatic Stubbing
    Great for:
    ● Automated Tests
    ● Complex Mocks
    ● Numerous Mocks
    Not the best for:
    ● Non-developers
    ● Simple use cases
    

    View Slide

67. @HandstandSam
    #DevFestDC
    Language Specific Wrapper Libraries
    ● Java - https://github.com/tomakehurst/wiremock
    ● Ruby - https://github.com/cheezy/service_mock
    ● Closure - https://github.com/alexanderjamesking/clj-wiremock
    ● PHP - https://github.com/rowanhill/wiremock-php
    ● Groovy - https://github.com/tomjankes/wiremock-groovy
    ● Node - https://github.com/jlidder/jswiremock
    

    View Slide

68. @HandstandSam
    #DevFestDC
    Usage in Java & JUnit
    

    View Slide

69. @HandstandSam
    #DevFestDC
    Programmatic Usage in Java for a Remote Server
    

    View Slide

70. @HandstandSam
    #DevFestDC
    Programmatic Usage in Java for a Remote Server
    

    View Slide

71. @HandstandSam
    #DevFestDC
    WireMock Syntax in Java
    {
    "request": {
    "method": "GET",
    "urlPath": "/categories"
    },
    "response": {
    "status": 200,
    "body": "[]"
    }
    }
    stubFor(get(urlPathEqualTo("/categories")).willReturn(aResponse().withStatus(200).withBody("[]")));
    

    View Slide

72. @HandstandSam
    #DevFestDC
    WireMock on Android
    

    View Slide

73. @HandstandSam
    #DevFestDC
    

    View Slide

74. @HandstandSam
    #DevFestDC
    WireMock 2.x on Android - Making it Work
    Hurdles:
    ● Java 7 Compatibility (Jetty 9.2.x)
    ● Apache HTTP Client
    

    View Slide

75. @HandstandSam
    #DevFestDC
    WireMock on Android - Dependencies
    dependencies {
    compile("com.github.tomakehurst:wiremock:2.6.0") {
    exclude group: 'org.apache.httpcomponents', module: 'httpclient'
    exclude group: 'org.json', module: 'json'
    exclude group: 'org.ow2.asm', module: 'asm'
    }
    compile 'org.apache.httpcomponents:httpclient-android:4.3.5.1'
    }
    

    View Slide

76. @HandstandSam
    #DevFestDC
    

    View Slide

77. @HandstandSam
    #DevFestDC
    

    View Slide

78. @HandstandSam
    #DevFestDC
    WireMock on Android - Project Config
    Recommended, but not required:
    android {
    defaultConfig {
    minSdkVersion 21
    multiDexEnabled true
    }
    }
    

    View Slide

79. @HandstandSam
    #DevFestDC
    BONUS DEMO:
    Usage From Android
    

    View Slide

80. @HandstandSam
    #DevFestDC
    Thanks!
    

    View Slide