Junit
Basic ( Fixtures / Annotation / Assert )
Fixtures
-
Fixtures
is a fixed state of a set of objects used as a baseline for running
tests. The purpose of a test fixture is to ensure that there is a
well known and fixed environment in which tests are run so that
results are repeatable. It includes
;
setUp()
- method which runs before every test invocation.
tearDown()
- method which runs
after every test method.
e.g.
: @Before, @After, @BeforeClass, @AfterClass
JUnit
Annotations
@Test
:
The annotation @Test identifies
that a method is a test method.
@Before
:
This method is executed before each test.
This method can prepare the test environment
e.g.
read input data, initialize the class
@After
:
This method is executed after each
test.
This method can cleanup the test environment.
It can also save memory by cleaning up expensive memory structures.
e.g.
delete temporary data, restore defaults.
@BeforeClass
: This method is executed once,
before the start of all tests.
This can be used to perform time intensive activities, for example
to connect to a database. Methods annotated with this annotation
need to be defined as static to work with JUnit.
@AfterClass
:
This method is executed once, after
all tests have been finished.
This can be used to perform clean-up activities, for example to
disconnect from a database. Methods annotated with this
annotation need to be defined as static to work with Junit.
@Ignore :
Ignores the test method.
This is useful when the underlying code has been changed and the
test case has not yet been adapted. Or if the execution time of
this test is too long to be included.
@Test
(expected = Exception.class) : Fails,
if the method does not throw the named exception.
@Test(timeout=100)
: Fails, if the method takes longer
than 100 milliseconds.
Assert -
A set of assert methods.
TestCase -
A test case defines the fixture to run
multiple tests.
TestResult -
A TestResult collects the results of
executing a test case.
TestSuite -
A TestSuite is a Composite of Tests.
Assert
statements
JUnit
provides static methods in the Assert class to test for certain
conditions.
These
assertion methods typically start with asserts and allow you to
specify the error message, the expected and the actual result.
An
assertion method compares the actual value returned by a test to the
expected value, and throws an AssertionException if the comparison
test fails.
fail(String)
:
Let
the method fail.
Might
be used to check that a certain part of the code is not reached.
Or
to have a failing test before the test code is implemented.
assertTrue([message],
boolean condition) :
Checks
that the boolean condition is true.
assertsEquals([String
message], expected, actual) :
Tests that two values are the same.
Note:
for arrays the reference is checked not the content of the arrays.
assertsEquals([String
message], expected, actual, tolerance) :
Test
that float or double values match.
The
tolerance is the number of decimals which must be the same.
assertNull([message],
object) :
Checks that the object is null.
assertNotNull([message],
object) :
Checks that the object is not null.
assertSame([String],
expected, actual) :
Checks that both variables refer to the same object.
assertNotSame([String],
expected, actual) :
Checks that both variables refer to different objects.
