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Package io.vertx.ext.unit

= Vertx unit Asynchronous polyglot unit testing.

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Package io.vertx.ext.unit Description

= Vertx unit Asynchronous polyglot unit testing. == Introduction Vertx Unit is designed for writing asynchronous unit tests with a polyglot API and running these tests in the JVM. Vertx Unit Api borrows from existing test frameworks like http://junit.org[JUnit] or http://qunitjs.com[QUnit] and follows the Vert.x practices. As a consequence Vertx Unit is the natural choice for testing Vert.x applications. To use vert.x unit, add the following dependency to the _dependencies_ section of your build descriptor: * Maven (in your `pom.xml`): [source,xml,subs="+attributes"] ---- ${maven.groupId} ${maven.artifactId} ${maven.version} test ---- * Gradle (in your `build.gradle` file): [source,groovy,subs="+attributes"] ---- testCompile ${maven.groupId}:${maven.artifactId}:${maven.version} ---- Vert.x unit can be used in different ways and run anywhere your code runs, it is just a matter of reporting the results the right way, this example shows the bare minimum test suite: [source,$lang] ---- examples.Examples#test_01 ---- The run method will execute the suite and go through all the tests of the suite. The suite can fail or pass, this does not matter if the outer world is not aware of the test result. [source,$lang] ---- examples.Examples#test_02 ---- When executed, the test suite now reports to the console the steps of the test suite: ---- Begin test suite the_test_suite Begin test my_test Passed my_test End test suite the_test_suite , run: 1, Failures: 0, Errors: 0 ---- The reporters option configures the reporters used by the suite runner for reporting the execution of the tests, see the <> section for more info. == Writing a test suite A test suite is a named collection of test case, a test case is a straight callback to execute. The suite can have lifecycle callbacks to execute _before_ and/or _after_ the test cases or the test suite that are used for initializing or disposing services used by the test suite. [source,$lang] ---- examples.Examples#writing_test_suite_01 ---- The API is fluent and therefore the test cases can be chained: [source,$lang] ---- examples.Examples#writing_test_suite_02 ---- The test cases declaration order is not guaranteed, so test cases should not rely on the execution of another test case to run. Such practice is considered as a bad one. Vertx Unit provides _before_ and _after_ callbacks for doing global setup or cleanup: [source,$lang] ---- examples.Examples#writing_test_suite_03 ---- The declaration order of the method does not matter, the example declares the _before_ callback before the test cases and _after_ callback after the test cases but it could be anywhere, as long as it is done before running the test suite. The _before_ callback is executed before any tests, when it fails, the test suite execution will stop and the failure is reported. The _after_ callback is the last callback executed by the testsuite, unless the _before_ callback reporter a failure. Likewise, Vertx Unit provides the _beforeEach_ and _afterEach_ callback that do the same but are executed for each test case: [source,$lang] ---- examples.Examples#writing_test_suite_04 ---- The _beforeEach_ callback is executed before each test case, when it fails, the test case is not executed and the failure is reported. The _afterEach_ callback is the executed just after the test case callback, unless the _beforeEach_ callback reported a failure. == Asserting Vertx Unit provides the TestContext object for doing assertions in test cases. The _context_ object provides the usual methods when dealing with assertions. === assertEquals Assert two objects are equals, works for _basic_ types or _json_ types. [source,$lang] ---- examples.Examples#asserting_01 ---- There is also an overloaded version for providing a message: [source,$lang] ---- examples.Examples#asserting_02 ---- Usually each assertion provides an overloaded version. === assertNotEquals The counter part of _assertEquals_. [source,$lang] ---- examples.Examples#asserting_03 ---- === assertNull Assert an object is null, works for _basic_ types or _json_ types. [source,$lang] ---- examples.Examples#asserting_04 ---- === assertNotNull The counter part of _assertNull_. [source,$lang] ---- examples.Examples#asserting_05 ---- === assertInRange The TestContext.assertInRange(double, double, double) targets real numbers. ---- examples.Examples#asserting_06 ---- === assertTrue and assertFalse Asserts the value of a boolean expression. [source,$lang] ---- examples.Examples#asserting_07 ---- === Failing Last but not least, _test_ provides a _fail_ method that will throw an assertion error: [source,$lang] ---- examples.Examples#asserting_08 ---- The failure can either be a _string_ as seen previously or an _error_. The _error_ object depends on the target language, for Java or Groovy it can be any class extending _Throwable- , for JavaScript it is an _error_, for Ruby it is an _Exception_. == Asynchronous testing The previous examples supposed that test cases were terminated after their respective callbacks, this is the default behavior of a test case callback. Often it is desirable to terminate the test after the test case callback, for instance: .The Async object asynchronously completes the test case [source,$lang] ---- examples.Examples#async_01 ---- <1> The callback exits but the test case is not terminated <2> The event callback from the bus terminates the test Creating an Async object with the TestContext.async() method marks the executed test case as non terminated. The test case terminates when the Async.complete() method is invoked. NOTE: When the `complete` callback is not invoked, the test case fails after a certain timeout. Several `Async` objects can be created during the same test case, all of them must be _completed_ to terminate the test. .Several Async objects provide coordination [source,$lang] ---- examples.Examples#async_02 ---- Async objects can also be used in _before_ or _after_ callbacks, it can be very convenient in a _before_ callback to implement a setup that depends on one or several asynchronous results: .Async starts an http server before test cases [source,$lang] ---- examples.Examples#async_03 ---- It is possible to wait until the completion of a specific Async, similar to Java's count-down latch: .Wait for completion [source, $lang] ---- examples.Examples#async_04(io.vertx.ext.unit.TestContext, io.vertx.core.Vertx, io.vertx.core.Handler) ---- WARNING: this should not be executed from the event loop! Async can also be created with an initial count value, it completes when the count-down reaches zero using Async.countDown(): .Wait until the complete count-down reaches zero [source, $lang] ---- examples.Examples#async_05(io.vertx.ext.unit.TestContext, io.vertx.core.Vertx, io.vertx.core.Handler) ---- Calling `complete()` on an async completes the async as usual, it actually sets the value to `0`. == Asynchronous assertions TestContext provides useful methods that provides powerful constructs for async testing: The TestContext.asyncAssertSuccess() method returns an Handler<AsyncResult<T>> instance that acts like Async, resolving the `Async` on success and failing the test on failure with the failure cause. [source,java] ---- examples.Examples#asyncAssertSuccess_01 ---- The TestContext.asyncAssertSuccess(io.vertx.core.Handler) method returns an Handler<AsyncResult<T>> instance that acts like Async, invoking the delegating Handler<T> on success and failing the test on failure with the failure cause. [source,java] ---- examples.Examples#asyncAssertSuccess_02 ---- The async is completed when the `Handler` exits, unless new asyncs were created during the invocation, which can be handy to _chain_ asynchronous behaviors: [source,java] ---- examples.Examples#asyncAssertSuccess_03 ---- The TestContext.asyncAssertFailure() method returns an Handler<AsyncResult<T>> instance that acts like Async, resolving the `Async` on failure and failing the test on success. [source,java] ---- examples.Examples#asyncAssertFailure_01(io.vertx.core.Vertx, io.vertx.ext.unit.TestContext) ---- The TestContext.asyncAssertFailure(io.vertx.core.Handler) method returns an Handler<AsyncResult<T>> instance that acts like Async, invoking the delegating Handler<Throwable> on failure and failing the test on success. [source,java] ---- examples.Examples#asyncAssertFailure_02(io.vertx.core.Vertx, io.vertx.ext.unit.TestContext) ---- The async is completed when the `Handler` exits, unless new asyncs were created during the invocation. == Repeating test When a test fails randomly or not often, for instance a race condition, it is convenient to run the same test multiple times to increase the failure likelihood of the test. .Repeating a test [source,$lang] ---- examples.Examples#repeating(io.vertx.core.Vertx) ---- When declared, _beforeEach_ and _afterEach_ callbacks will be executed as many times as the test is executed. NOTE: test repetition are executed sequentially == Sharing objects The TestContext has `get`/`put`/`remove` operations for sharing state between callbacks. Any object added during the _before_ callback is available in any other callbacks. Each test case will operate on a copy of the shared state, so updates will only be visible for a test case. .Sharing state between callbacks [source,$lang] ---- examples.Examples#sharing_01 ---- WARNING: sharing any object is only supported in Java, other languages can share only basic or json types. Other objects should be shared using the features of that language. == Running When a test suite is created, it won't be executed until the run() method is called. .Running a test suite [source,$lang] ---- examples.Examples#running_01 ---- The test suite can also be run with a specified Vertx instance: .Provides a Vertx instance to run the test suite [source,$lang] ---- examples.Examples#running_02 ---- When running with a `Vertx` instance, the test suite is executed using the Vertx event loop, see the <> section for more details. A test suite can be run with the Vert.x Command Line Interface with the `vertx test` command: .Running a test suite with the Vert.x CLI [source] ---- > vertx test the_test_suite.js Begin test suite the_test_suite Succeeded in deploying verticle Begin test my_test_case Passed my_test_case End test suite my_suite , run: 1, Failures: 0, Errors: 0 ---- Such test suite just need to be executed via the run() command, the `vertx test` command takes care of configuring reporting, timeout, etc..., pretty much like in this example: [source,$lang] ---- examples.Examples#test_01 ---- The `vertx test` command extends the `vertx run` command. The exit behavior of the JVM is changed the JVM exits when the test suite is executed and a return value is provided indicating the tests success (0) or failure (1). NOTE: several test suites can executed in the same verticle, Vert.x Unit waits until completion of all suite executed. === Test suite completion No assumptions can be made about when the test suite will be completed, and if some code needs to be executed after the test suite, it should either be in the test suite _after_ callback or as callback of the Completion: .Test suite execution callback [source,$lang] ---- examples.Examples#completion_01 ---- The Completion object provides also a Completion.resolve(io.vertx.core.Future<T>) method that takes a `Future` object, this `Future` will be notified of the test suite execution: .Resolving the start Future with the test suite [source,$lang] ---- examples.Examples#completion_02 ---- This allow to easily create a _test_ verticle whose deployment is the test suite execution, allowing the code that deploys it to be easily aware of the success or failure. The completion object can also be used like a latch to block until the test suite completes. This should be used when the thread running the test suite is not the same than the current thread: .Blocking until the test suite completes [source,$lang] ---- examples.Examples#completion_03 ---- The `await` throws an exception when the thread is interrupted or a timeout is fired. The Completion.awaitSuccess() is a variation that throws an exception when the test suite fails. .Blocking until the test suite succeeds [source,$lang] ---- examples.Examples#completion_04 ---- === Time out Each test case of a test suite must execute before a certain timeout is reached. The default timeout is of _2 minutes_, it can be changed using _test options_: .Setting the test suite timeout [source,$lang] ---- examples.Examples#running_05 ---- [[event_loop]] === Event loop Vertx Unit execution is a list of tasks to execute, the execution of each task is driven by the completion of the previous task. These tasks should leverage Vert.x event loop when possible but that depends on the current execution context (i.e the test suite is executed in a `main` or embedded in a `Verticle`) and wether or not a `Vertx` instance is configured. The TestOptions.setUseEventLoop(java.lang.Boolean) configures the usage of the event loop: .Event loop usage |=== | | useEventLoop:null | useEventLoop:true | useEventLoop:false | `Vertx` instance | use vertx event loop | use vertx event loop | force no event loop | in a `Verticle` | use current event loop | use current event loop | force no event loop | in a _main_ | use no event loop | raise an error | use no event loop |=== The default `useEventLoop` value is `null`, that means that it will uses an event loop when possible and fallback to no event loop when no one is available. [[reporting]] == Reporting Reporting is an important piece of a test suite, Vertx Unit can be configured to run with different kind of reporters. By default no reporter is configured, when running a test suite, _test options_ can be provided to configure one or several: .Using the console reporter and as a junit xml file [source,$lang] ---- examples.Examples#reporter_01 ---- === Console reporting Reports to the JVM `System.out` and `System.err`: to:: _console_ format:: _simple_ or _junit_ === File reporting Reports to a file, a `Vertx` instance must be provided: to:: _file_ `:` _dir name_ format:: _simple_ or _junit_ example:: `file:.` The file reporter will create files in the configured directory, the files will be named after the test suite name executed and the format (i.e _simple_ creates _txt_ files and _junit_ creates _xml_ files). === Log reporting Reports to a logger, a `Vertx` instance must be provided: to:: _log_ `:` _logger name_ example:: `log:mylogger` === Event bus reporting Reports events to the event bus, a `Vertx` instance must be provided: to:: _bus_ `:` _event bus address_ example:: `bus:the-address` It allow to decouple the execution of the test suite from the reporting. The messages sent over the event bus can be collected by the EventBusCollector and achieve custom reporting: [source,$lang] ---- examples.Examples#reporter_02 ---- [[vertx_integration]] == Vertx integration By default, assertions and failures must be done on the TestContext and throwing an assertion error works only when called by Vert.x Unit: [source,$lang] ---- examples.Examples#vertxInteg1 ---- In a regular Vert.x callback, the failure will be ignored: [source,$lang] ---- examples.Examples#vertxInteg2 ---- Since Vert.x 3.3, a global exception handler can be set to report the event loop uncaught exceptions: [source,$lang] ---- examples.Examples#vertxInteg3 ---- The exception handler is set during the _before_ phase, the TestContext is shared between each _before_, _test_ and _after_ phase. So the exception handler obtained during the _before_ phase is correct. == Junit integration Although Vertx Unit is polyglot and not based on JUnit, it is possible to run a Vertx Unit test suite or a test case from JUnit, allowing you to integrate your tests with JUnit and your build system or IDE. .Run a Java class as a JUnit test suite [source,java] ---- examples.junit.JUnitTestSuite ---- The VertxUnitRunner uses the junit annotations for introspecting the class and create a test suite after the class. The methods should declare a TestContext argument, if they don't it is fine too. However the `TestContext` is the only way to retrieve the associated Vertx instance of perform asynchronous tests. The JUnit integration is also available for the Groovy language with the `io.vertx.groovy.ext.unit.junit.VertxUnitRunner` runner. === Running a test on a Vert.x context By default the thread invoking the test methods is the JUnit thread. The RunTestOnContext JUnit rule can be used to alter this behavior for running these test methods with a Vert.x event loop thread. Thus there must be some care when state is shared between test methods and Vert.x handlers as they won't be on the same thread, e.g incrementing a counter in a Vert.x handler and asserting the counter in the test method. One way to solve this is to use proper synchronization, another is to execute test methods on a Vert.x context that will be propagated to the created handlers. For this purpose the RunTestOnContext rule needs a Vertx instance. Such instance can be provided, otherwise the rule will manage an instance under the hood. Such instance can be retrieved when the test is running, making this rule a way to manage a Vertx instance as well. .Run a Java class as a JUnit test suite [source,java] ---- examples.junit.RunOnContextJUnitTestSuite ---- The rule can be annotated by @Rule or @ClassRule, the former manages a Vert.x instance per test, the later a single Vert.x for the test methods of the class. WARNING: keep in mind that you cannot block the event loop when using this rule. Usage of classes like `CountDownLatch` or similar classes must be done with care. === Timeout The Vert.x Unit 2 minutes timeout can be overriden with the `timeout` member of the `@Test` annotation: .Configure the timeout at the test level [source,java] ---- examples.junit.JunitTestWithTimeout ---- For a more global configuration, the Timeout rule can be used: .Configure the timeout at the class level [source,java] ---- examples.junit.TimeoutTestSuite ---- NOTE: the `@Test` timeout overrides the the Timeout rule. === Parameterized tests JUnit provides useful `Parameterized` tests, Vert.x Unit tests can be ran with this particular runner thanks to the VertxUnitRunnerWithParametersFactory: .Running a Vert.x Unit parameterized test [source,java] ---- examples.junit.SimpleParameterizedTest ---- Parameterized tests can also be done in Groovy with the `io.vertx.groovy.ext.unit.junit.VertxUnitRunnerWithParametersFactory`. === Repeating a test When a test fails randomly or not often, for instance a race condition, it is convenient to run the same test multiple times to increase the likelihood failure of the test. With JUnit a test has to be annotated with Repeat to be repeated. The test must also define the RepeatRule among its rules. .Repeating a test with JUnit [source,$lang] ---- examples.junit.RepeatingTest ---- When declared, _before_ and _after_ life cycle will be executed as many times as the test is executed. NOTE: test repetition are executed sequentially === Using with other assertion libraries Vert.x Unit usability has been greatly improved in Vert.x 3.3. You can now write tests using http://hamcrest.org/[Hamcrest], http://joel-costigliola.github.io/assertj/[AssertJ], https://github.com/rest-assured/rest-assured/[Rest Assured], or any assertion library you want. This is made possible by the global exception handler described in <>. You can find Java examples of using Vert.x Unit with Hamcrest and AssertJ in the https://github.com/vert-x3/vertx-examples/tree/master/unit-examples[vertx-examples] project. == Java language integration === Test suite integration The Java language provides classes and it is possible to create test suites directly from Java classes with the following mapping rules: The testSuiteObject argument methods are inspected and the public, non static methods with TestContext parameter are retained and mapped to a Vertx Unit test suite via the method name: * `before` : before callback * `after` : after callback * `beforeEach` : beforeEach callback * `afterEach` : afterEach callback * when the name starts with _test_ : test case callback named after the method name .Test suite written using a Java class [source,java] ---- examples.junit.MyTestSuite ---- This class can be turned into a Vertx test suite easily: .Create a test suite from a Java object [source,java] ---- examples.junit.Snippets#testSuite() ----
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