问题
I have a test suite where i am using parallelism by using annotation like : test name="All Regular Tests" parallel="tests" thread-count="30"
Now, let's say we have multiple @test annotation in one class. and it has @beforeclass annotation method as well. So when separate thread will pick the tests from same class, will it execute the @beforeclass methods in both threads or will it share the same data.
Or shall i use parallel="methods", what is the correct way ?
Not able to understand the concept of parallelism.
回答1:
I can see why you are confused.
It makes no sense to use parallel="tests" in the test tag.
parallel="tests" is dictating that all the defined in the XML are run in different threads. But you are assigning that to a test level, so it will only apply that option for that test.
You have two options here.
To put the multithreading option at a suite level, with the "tests" parallelization:
<suite name = "ParallelTesting" parallel="tests" thread-count="2">
Or to put it on the test level, with "method" option:
<test name = "Test Parallelism" parallel="method" thread-count="2">
So:
- "tests": for each in the XML file.
- "method": for each @Test method in wherever you put the property (all the @Tests in the suite, all the @Tests in a class, etc.)
Regarding yout second question, no, it will run the @BeforeClass only once. You can put it to the test very easily:
XML File: parallel=tests on suite level:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE suite SYSTEM "http://testng.org/testng-1.0.dtd" >
<suite name = "ParallelTesting" parallel="tests" thread-count="2">
<test name = "Test Parallelism 1" >
<classes>
<class name = "com.test.testing.test.TestClass"/>
</classes>
</test>
<test name = "Test Parallelism 2" >
<classes>
<class name = "com.test.testing.test.TestClass2"/>
</classes>
</test>
</suite>
Test Class 1:
public class TestClass {
@BeforeClass
public void beforeClass() {
System.out.println("Class 1 - Before Class with Thread Id:- "+ Thread.currentThread().getId());
}
@Test
public void testA() {
System.out.println("Class 1 - Test Case A with Thread Id:- " + Thread.currentThread().getId());
}
@Test
public void testB() {
System.out.println("Class 1 - Test Case B with Thread Id:- " + Thread.currentThread().getId());
}
}
Test Class 2:
public class TestClass2 {
@BeforeClass
public void beforeClass() {
System.out.println("Class 2 - Before Class with Thread Id:- "+ Thread.currentThread().getId());
}
@Test
public void testA() {
System.out.println("Class 2 - Test Case A with Thread Id:- " + Thread.currentThread().getId());
}
@Test
public void testB() {
System.out.println("Class 2 - Test Case B with Thread Id:- " + Thread.currentThread().getId());
}
}
Output:
Class 1 - Before Class with Thread Id:- 12
Class 2 - Before Class with Thread Id:- 13
Class 2 - Test Case A with Thread Id:- 13
Class 1 - Test Case A with Thread Id:- 12
Class 2 - Test Case B with Thread Id:- 13
Class 1 - Test Case B with Thread Id:- 12
===============================================
ParallelTesting
Total tests run: 4, Failures: 0, Skips: 0
===============================================
The two other variations of parallelization are (using the same classes above):
XML File: parallel=method on suite level:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE suite SYSTEM "http://testng.org/testng-1.0.dtd" >
<suite name = "ParallelTesting2" parallel="methods" thread-count="2">
<test name = "Test Parallelism 1" >
<classes>
<class name = "com.test.testing.test.TestClass"/>
</classes>
</test>
<test name = "Test Parallelism 2" >
<classes>
<class name = "com.test.testing.test.TestClass2"/>
</classes>
</test>
</suite>
Output:
Class 1 - Before Class with Thread Id:- 12
Class 1 - Test Case B with Thread Id:- 13
Class 1 - Test Case A with Thread Id:- 12
Class 2 - Before Class with Thread Id:- 14
Class 2 - Test Case A with Thread Id:- 14
Class 2 - Test Case B with Thread Id:- 15
XML File: parallel=method on test level:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE suite SYSTEM "http://testng.org/testng-1.0.dtd" >
<suite name = "ParallelTesting2" >
<test name = "Test Parallelism 1" parallel="methods" thread-count="2">
<classes>
<class name = "com.test.testing.test.TestClass"/>
</classes>
</test>
<test name = "Test Parallelism 2" parallel="methods" thread-count="2">
<classes>
<class name = "com.test.testing.test.TestClass2"/>
</classes>
</test>
</suite>
Output:
Class 1 - Before Class with Thread Id:- 12
Class 1 - Test Case A with Thread Id:- 12
Class 1 - Test Case B with Thread Id:- 13
Class 2 - Before Class with Thread Id:- 14
Class 2 - Test Case B with Thread Id:- 15
Class 2 - Test Case A with Thread Id:- 14
And finally, what I mention it wouldn't make sense to do:
XML File: parallel=tests on test level:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE suite SYSTEM "http://testng.org/testng-1.0.dtd" >
<suite name = "ParallelTesting2" >
<test name = "Test Parallelism 1" parallel="tests" thread-count="2">
<classes>
<class name = "com.test.testing.test.TestClass"/>
</classes>
</test>
<test name = "Test Parallelism 2" parallel="tests" thread-count="2">
<classes>
<class name = "com.test.testing.test.TestClass2"/>
</classes>
</test>
</suite>
Output:
Class 1 - Before Class with Thread Id:- 1
Class 1 - Test Case A with Thread Id:- 1
Class 1 - Test Case B with Thread Id:- 1
Class 2 - Before Class with Thread Id:- 1
Class 2 - Test Case A with Thread Id:- 1
Class 2 - Test Case B with Thread Id:- 1
As you can see in that last example, everything runs on the same thread because you are asking to each test (group of methods) to run tests in parallel.
来源：https://stackoverflow.com/questions/58749157/beforeclass-methods-get-exexcuted-in-same-thread-if-we-put-parallel-tests-in