Java Reference
In-Depth Information
elements. In our case,
JU
nit calls the three-argument constructor
E
with the first
element in the array, itself an array:
{2,
1,
1}
.
JU
nit then calls each
@Test
method
F
as usual.
JU
nit repeats the process for the next array in the
getTestParameters
collection
D
.
When you compare the test results with the previous example, you see that instead
of running one test, the parameterized
JU
nit test runner ran the same method three
times, once for each value in our
@Parameters
collection.
The
JU
nit class
Parameterized
is one of
JU
nit's many
test runners.
A test runner
allows you to tell
JU
nit how a test should be run. Next, we look at the other
JU
nit
test runners.
2.3
JUnit test runners
When you're first writing tests, you want them to run as quickly and easily as possible.
You should be able to make testing part of the development cycle:
code-run-test-code
(or
test-code run-test
if you're test-first inclined). There are
IDE
s and compilers for quickly
building and running applications;
JU
nit lets you build and run tests.
2.3.1
Test runner overview
JU
nit 4 is built with backward compatibility with version 3.8.x. Because the 4.x version
of
JU
nit is completely different from the 3.x versions, it should be possible to execute
not only
JU
nit 4 tests but also 3.x-style tests. That's why in its latest versions
JU
nit pro-
vides different runners (listed in table 2.3) for running
JU
nit 3.x tests,
JU
nit 4 tests,
and different sets of tests.
Table 2.3
JUnit 4 test runners
Runner
Purpose
org.junit.internal.runners.JUnit38ClassRunner
This runner is included in the cur-
rent release of JUnit only for
backward compatibility. It will
start the test case as a JUnit 3.8
test case.
This runner will start the test
case as a JUnit 4 test case.
org.junit.runners.JUnit4
A
Parameterized
test runner
runs same sets of tests with dif-
ferent parameters.
org.junit.runners.Parameterized
org.junit.runners.Suite
The
Suite
is a container that
can hold different tests. The
Suite
is also a runner that exe-
cutes all the
@Test
annotated
methods in a test class.
