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 JUnit or QUnit and follows the Vert.x practices.
As a consequence Vertx Unit is the natural choice for testing Vert.x applications.
It 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:
var TestSuite = require("vertx-unit-js/test_suite");
var suite = TestSuite.create("the_test_suite");
suite.test("my_test_case", function (context) {
var s = "value";
context.assertEquals("value", s);
});
suite.run();
The 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.
var TestSuite = require("vertx-unit-js/test_suite");
var suite = TestSuite.create("the_test_suite");
suite.test("my_test_case", function (context) {
var s = "value";
context.assertEquals("value", s);
});
suite.run({
"reporters" : [
{
"to" : "console"
}
]
});
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 option configures the reporters used by the suite runner for reporting the execution of the tests, see the Running 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.
var TestSuite = require("vertx-unit-js/test_suite");
var suite = TestSuite.create("the_test_suite");
suite.test("my_test_case_1", function (context) {
// Test 1
});
suite.test("my_test_case_2", function (context) {
// Test 2
});
suite.test("my_test_case_3", function (context) {
// Test 3
});
The API is fluent and therefore the test cases can be chained:
var TestSuite = require("vertx-unit-js/test_suite");
var suite = TestSuite.create("the_test_suite");
suite.test("my_test_case_1", function (context) {
// Test 1
}).test("my_test_case_2", function (context) {
// Test 2
}).test("my_test_case_3", function (context) {
// Test 3
});
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:
var TestSuite = require("vertx-unit-js/test_suite");
var suite = TestSuite.create("the_test_suite");
suite.before(function (context) {
// Test suite setup
}).test("my_test_case_1", function (context) {
// Test 1
}).test("my_test_case_2", function (context) {
// Test 2
}).test("my_test_case_3", function (context) {
// Test 3
}).after(function (context) {
// Test suite cleanup
});
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:
var TestSuite = require("vertx-unit-js/test_suite");
var suite = TestSuite.create("the_test_suite");
suite.beforeEach(function (context) {
// Test case setup
}).test("my_test_case_1", function (context) {
// Test 1
}).test("my_test_case_2", function (context) {
// Test 2
}).test("my_test_case_3", function (context) {
// Test 3
}).afterEach(function (context) {
// Test case cleanup
});
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.
suite.test("my_test_case", function (context) {
context.assertEquals(10, callbackCount);
});
There is also an overloaded version for providing a message:
suite.test("my_test_case", function (context) {
context.assertEquals(10, callbackCount, "Should have been 10 instead of " + callbackCount);
});
Usually each assertion provides an overloaded version.
assertNotEquals
The counter part of assertEquals.
suite.test("my_test_case", function (context) {
context.assertNotEquals(10, callbackCount);
});
assertNull
Assert an object is null, works for basic types or json types.
suite.test("my_test_case", function (context) {
context.assertNull(null);
});
assertNotNull
The counter part of assertNull.
suite.test("my_test_case", function (context) {
context.assertNotNull("not null!");
});
assertInRange
The assertInRange
targets real numbers.
suite.test("my_test_case", function (context) { // Assert that 0.1 is equals to 0.2 +/- 0.5 context.assertInRange(0.1, 0.2, 0.5); });
assertTrue and assertFalse
Asserts the value of a boolean expression.
suite.test("my_test_case", function (context) {
context.assertTrue(var);
context.assertFalse(value > 10);
});
Failing
Last but not least, test provides a fail method that will throw an assertion error:
suite.test("my_test_case", function (context) {
context.fail("That should never happen");
// Following statements won't be executed
});
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:
suite.test("my_test_case", function (context) {
var async = context.async();
eventBus.consumer("the-address", function (msg) {
(2)
async.complete();
});
(1)
});
-
The callback exits but the test case is not terminated
-
The event callback from the bus terminates the test
Creating an Async
object with the async
method marks the
executed test case as non terminated. The test case terminates when the 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.
suite.test("my_test_case", function (context) {
var async1 = context.async();
var client = vertx.createHttpClient();
var req = client.get(8080, "localhost", "/");
req.exceptionHandler(function (err) {
context.fail(err.getMessage())});
req.handler(function (resp) {
context.assertEquals(200, resp.statusCode());
async1.complete();
});
req.end();
var async2 = context.async();
vertx.eventBus().consumer("the-address", function (msg) {
async2.complete();
});
});
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:
suite.before(function (context) {
var async = context.async();
var server = vertx.createHttpServer();
server.requestHandler(requestHandler);
server.listen(8080, function (ar, ar_err) {
context.assertTrue(ar_err == null);
async.complete();
});
});
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.
var TestSuite = require("vertx-unit-js/test_suite");
TestSuite.create("my_suite").before(function (context) {
// host is available for all test cases
context.put("host", "localhost");
}).beforeEach(function (context) {
// Generate a random port for each test
var port = helper.randomPort();
// Get host
var host = context.get("host");
// Setup server
var async = context.async();
var server = vertx.createHttpServer();
server.requestHandler(function (req) {
req.response().setStatusCode(200).end();
});
server.listen(port, host, function (ar, ar_err) {
context.assertTrue(ar_err == null);
context.put("port", port);
async.complete();
});
}).test("my_test", function (context) {
// Get the shared state
var port = context.get("port");
var host = context.get("host");
// Do request
var client = vertx.createHttpClient();
var req = client.get(port, host, "/resource");
var async = context.async();
req.handler(function (resp) {
context.assertEquals(200, resp.statusCode());
async.complete();
});
req.end();
});
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.
suite.run();
The test suite can also be ran with a specified Vertx
instance:
suite.run(vertx);
When running with a Vertx
instance, the test suite is executed using the Vertx event loop, see the [eventloop]
section for more details.
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
TestCompletion
:
var completion = suite.run(vertx);
// Simple completion callback
completion.handler(function (ar, ar_err) {
if (ar_err == null) {
console.log("Test suite passed!");
} else {
console.log("Test suite failed:");
ar_err.printStackTrace();
};
});
The TestCompletion
object provides also a resolve
method that
takes a Future
object, this Future
will be notified of the test suite execution:
var completion = suite.run();
// When the suite completes, the future is resolved
completion.resolve(startFuture);
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:
var completion = suite.run();
// Wait until the test suite completes
completion.await();
The await
throws an exception when the thread is interrupted or a timeout is fired.
The awaitSuccess
is a variation that throws an exception when
the test suite fails.
var completion = suite.run();
// Wait until the test suite succeeds otherwise throw an exception
completion.awaitSuccess();
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:
var options = {
"timeout" : 10000
};
// Run with a 10 seconds time out
suite.run(options);
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 useEventLoop
configures the usage of the event
loop:
useEventLoop:null | useEventLoop:true | useEventLoop:false | |
---|---|---|---|
|
use vertx event loop |
use vertx event loop |
force no event loop |
in a |
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 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:
// Report to console
var consoleReport = {
"to" : "console"
};
// Report junit files to the current directory
var junitReport = {
"to" : "file:.",
"format" : "junit"
};
suite.run({
"reporters" : [
consoleReport,
junitReport
]
});
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:
var EventBusCollector = require("vertx-unit-js/event_bus_collector");
var collector = EventBusCollector.create(vertx, {
"reporters" : [
{
"to" : "file:report.xml",
"format" : "junit"
}
]
});
collector.register("the-address");
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.
RunWith(io.vertx.ext.unit.junit.VertxUnitRunner.class)
public class JUnitTestSuite {
Test
public void testSomething(Context context) {
context.assertFalse(false);
}
}
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.
A single test case can also be executed with a TestCase
:
TestCase.
create("my_test_case", context -> {
context.assertTrue(true);
}).
awaitSuccess(); (1)
-
Block until the test case is executed
Java language integration
The Java language provides classes and it is possible to create test suites directly from Java classes with the following mapping rules:
The 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
public class MyTestSuite {
public void testSomething(TestContext context) {
context.assertFalse(false);
}
}
This class can be turned into a Vertx test suite easily:
TestSuite suite = TestSuite.create(new MyTestSuite());