HttpClientMock

HttpClientMock is a library for mocking Apache HttpClient. It has an intuitive API for defining client behaviour and verifying number of made requests. It works with HttpClient 4.X and 5.X.

Installation
Usage
Request matching
Define response
Verification
Matching query and form parameters
Debugging
Example 1
Example 2
Release notes

Installation

HttpClientMock is available in Maven Central Repository.

For mocking HttpClient 4.x use HttpClientMock 1.X.
For mocking HttpClient 5.x use HttpClientMock 2.X.

Usage

Record

Working with HttpClientMock starts with defining client behaviour. Before code under tests starts HttpClientMock must know how to respond to every request.

HttpClientMock httpClientMock = new HttpClientMock();
httpClientMock.onGet("http://localhost/login")
  .withParameter("user","john")
  .doReturn("Ok");
httpClientMock.onPost("http://localhost/login").doReturnStatus(501);

Replay

Code under test starts and uses HttpClientMock with defined behaviour.

httpClient.execute(new HttpGet("http://localhost/login?user:john")); // returns response with body "Ok"
httpClient.execute(new HttpPost("http://localhost/login")); // returns response with status 501

Verify

When code under test finishes, HttpClientMock allows to check number of made request. It is possible to use the same set of conditions as for defining mock behaviour.

httpClientMock.verify().get("http://localhost/login").withParameter("user","john").called();
httpClientMock.verify().post("http://localhost/login").notCalled();

Request matching

HTTP method

HttpClientMock supports all Http methods.

httpClientMock.onGet().doReturn("get");
httpClientMock.onPost().doReturn("post");
httpClientMock.onPut().doReturn("put");
httpClientMock.onDelete().doReturn("delete");
httpClientMock.onOptions().doReturn("options");
httpClientMock.onHead().doReturn("head");

URL

Every onGet(), onPost(), .... method accept URL. It is possible to write:

httpClientMock.onGet("http://localhost/login?user=john").doReturnStatus(200);

which is equal to

httpClientMock.onGet()
  .withHost("http://localhost")
  .withPath("/login")
  .withParameter("user","john")
  .doReturnStatus(200);

It is possible to define default host using HttpClientMock constructor, so later methods can accept relative URL-s.

HttpClientMock httpClientMock = new HttpClientMock("http://localhost");
httpClientMock.onGet("/login").doReturn("ok");
httpClientMock.onPost("/edit?user=john").doReturnStatus(200);

httpClientMock.onGet("http://www.google.com").doReturn("Google") // Absolute paths still work.

Host, path, parameters conditions

It is possible to define each part of url separately.

httpClientMock.onGet()
  .withHost("http://localhost")
  .withPath("/login")
  .withParameter("user","john")
  .doReturnStatus(200);

Header condition

httpClientMock.onGet("http://localhost/login")
  .withHeader("tracking","123")
  .doReturn("ok");

Form parameters

httpClientMock.onPost("/login")
      .withFormParameter("username", "John")
      .withFormParameter("password", Matchers.containsString("secret"))
    .doReturnStatus(200);

Body condition

httpClientMock.onGet("http://localhost/login")
  .withBody("tracking",containsString("123"))
  .doReturn("ok");

Custom condition

Condition fooCondition = request -> request.getUri().contains("foo");
httpClientMock.onGet("http://localhost/foo/bar")
  .with(fooCondition)
  .doReturn("yes");

Matchers

Every condition method accepts Hamcrest Matcher which allows to define custom conditions on requests.

httpClientMock.onGet("http://localhost")
  .withPath(containsString("login"))
  .withParameter("user",equalToIgnoringCase("John"));

Multiple matching rules

If request matches more then one rule, then last defined one is used.

None rule matche

If request doesn't matche any rule, HttpClientMock return response with status 404.

Define response

Response

Response with provided body and status 200.

httpClientMock.onGet("http://localhost").doReturn("my response");

Status

Response with empty body and provided status

httpClientMock.onGet("http://localhost").doReturnStatus(300);
httpClientMock.onGet("http://localhost").doReturn("Overloaded").withStatus(500);

Exception

Instead of returning response it throws defined exception.

httpClientMock.onGet("http://localhost").doThrowException(new IOException());

Custom action

Action echo = r -> {
  HttpEntity entity = ((HttpEntityEnclosingRequestBase) r.getHttpRequest()).getEntity();
  BasicHttpResponse response = new BasicHttpResponse(new ProtocolVersion("http", 1, 1), 200, "ok");
  response.setEntity(entity);
  return response;
};
httpClientMock.onGet("http://localhost").doAction(echo);

Response header

httpClientMock.onPost("/login").doReturn("foo").withHeader("tracking", "123");

Response status

httpClientMock.onPost("/login?user=bar").doReturn("Wrong user").withStatus(403);

JSON

Response with provided body, status 200 and content type "application/json"

httpClientMock.onPost("/login").doReturnJSON("{foo:1}");

XML

Response with provided body, status 200 and content type "application/xml"

httpClientMock.onPost("/login").doReturnXML("<foo>bar</foo>");

Multiple actions

It is possible to add multiple actions to one rule. Every call will use next action until last is reached.

httpClientMock.onPut("/addUser")
  .doReturn("ok")
  .doReturnStatus(500);

httpClientMock.execute(new HttpPut("http://localhost/addUser")); //returns "ok"
httpClientMock.execute(new HttpPut("http://localhost/addUser")); //returns status 500
httpClientMock.execute(new HttpPut("http://localhost/addUser")); //returns status 500

Verification

HttpClientMock allows to check how many calls were made. Verification supports the same set of conditions us rule defining.

httpClientMock.verify().get("http://localhost").called();

httpClientMock.verify().get("http://localhost/login")
  .withParameter("user","john")
  .called();

httpClientMock.verify().get("http://localhost/login")
  .withParameter("user","Ben")
  .notCalled();

httpClientMock.verify().delete().notCalled();

httpClientMock.verify().get().called(greaterThanOrEqualTo(1));

Matching query and form parameters

There are two methods that control HttpClientMock behaviour when request contains extra form or query parameters:

withExtraParameters: allows request to contain extra query parameters
withoutExtraParameters: disallows request to contain extra query parameters
withExtraFormParameters: allows request to contain extra form parameters
withoutExtraFormParameters: disallows request to contain extra form parameters

Examples:

httpClientMock.onPost("/login")
  .withParameter("user","John")
  .withoutExtraParameters()
  .doReturn("ok");

Above condition will not match request http://www.example.com/login?user=John&password=secret because it contains extra parameter password.

httpClientMock.onPost("/login")
  .withParameter("user","John")
  .withExtraParameters()
  .doReturn("ok");

Above condition will match request http://www.example.com/login?user=John&password=secret although it contains extra parameter password.

By default HttpClientMock matches requests with extra form and query parameters.

Debugging

HttpClientMock can help you to debug your code by displaying information which matchers matched your request. You can use HttpClientMock#debugOn to turn it on and HttpClientMock#debugOff to turn it off. Example message:

Rule 1:
	MATCHES		EXPECTED
	true		HTTP method is GET
	true		schema is "http"
	true		host is "localhost"
	false		path is "/login"
	true		port is empty

Example 1

// DEFINE BEHAVIOUR
HttpClientMock httpClientMock = new HttpClientMock("http://localhost:8080");
httpClientMock.onGet("/login?user=john").doReturnJSON("{permission:1}");
httpClientMock.onPost("/edit")
  .withParameter("user","John")
  .doReturn("ok")
  .doReturnStatus(503);

// EXECUTION
// request to http://localhost:8080/login?user=john returns JSON {permission:1}
// first request to http://localhost:8080/edit?user=john returns message "ok"
// second request to http://localhost:8080/edit?user=john returns request with status 503

// VERIFICATION
httpClientMock.verify().get("/login?user=john").called();
httpClientMock.verify().post("/edit?user=john").called(2);
httpClientMock.verify().delete().notCalled();

Example 2

// DEFINE BEHAVIOUR
HttpClientMock httpClientMock = new HttpClientMock();
httpClientMock.onGet("http://localhost:8080/login").doReturn("Missing parameter user").withStatus(400);
httpClientMock.onGet("http://localhost:8080/login")
  .withParameter("user","JJohn")
  .doReturn("Wrong user name").withStatus(403);
httpClientMock.onGet("http://localhost:8080/login")
  .withParameter("user","John")
  .doReturn("ok");
  
// EXECUTION
// request to http://localhost:8080/login?user=john returns message "ok"

// VERIFICATION
httpClientMock.verify().get("/login?user=john").called();

Release notes

2.1.1

Fixed MalformedURLException when using not absolute paths

2.1.0

Added method withStatus accepting status code and text

2.0.0

Added support for HttpClient 5.
Removed methods for mocking URL reference

1.9.1

Fixed MalformedURLException when using not absolute paths

1.9.0

Added method withStatus accepting status code and text

1.8.0

Added methods {withExtraParameters, withoutExtraParameters, withExtraFormParameters, withoutExtraFormParameters} to better control form and query parameters matching. WARNING Breaking changes: Since this version by default HttpClientMock matches requests with extra form and query parameters.

1.7.0

Added methods (withFormParameter, withFormParameters) for matching form parameters (URL encode parameters).
Added action (doReturnFormParams) which return response with body containing provided form parameters.

1.6.0

Added possibility to set response Content-Type.
Fixed wrong Contet-Type in methods 'doReturnXML', doReturnJSON

1.5.0

Added possibility to add cookies to the response.

PawelAdamski/HttpClientMock