Test parallelization in CI in Selenium Java - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to set the number of threads for parallel test execution in TestNG.

Selenium Java

suite.setParallel("[1]");

Drag options to blanks, or click blank then click option'

Amethods

Btests

Cclasses

Dinstances

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'methods' runs individual test methods in parallel, not whole classes.

Using 'tests' runs test tags in parallel, which is different from classes.

Setting parallel to classes runs test classes in parallel threads.

2fill in blank

medium

Complete the code to set the thread count for parallel tests in TestNG.

Selenium Java

suite.setThreadCount([1]);

Drag options to blanks, or click blank then click option'

A5

B1

C3

D10

Attempts:

3 left

💡 Hint

Common Mistakes

Setting thread count to 1 disables parallelism.

Choosing too low thread count limits parallel execution.

Setting thread count to 10 allows up to 10 tests to run in parallel.

3fill in blank

hard

Fix the error in the TestNG XML configuration to enable parallel test execution.

Selenium Java

<suite name="Suite1" parallel="[1]" thread-count="5">

Drag options to blanks, or click blank then click option'

Aclasses

Btrue

Cfalse

Dparallel

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'true' or 'false' as the value causes configuration errors.

Using 'parallel' as a value is invalid.

The parallel attribute must be set to a valid value like classes to enable parallel execution.

4fill in blank

hard

Fill both blanks to configure TestNG for parallel execution of test methods with 8 threads.

Selenium Java

<suite name="Suite2" parallel="[1]" thread-count="[2]">

Drag options to blanks, or click blank then click option'

Amethods

Bclasses

C8

D5

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing 'classes' with thread count 5 when 8 is needed.

Using invalid parallel values.

Setting parallel to methods runs test methods in parallel, and thread-count to 8 allows 8 threads.

5fill in blank

hard

Fill all three blanks to create a TestNG XML snippet that runs tests in parallel by instances with 4 threads and a suite name 'ParallelSuite'.

Selenium Java

<suite name="[1]" parallel="[2]" thread-count="[3]">

Drag options to blanks, or click blank then click option'

AParallelSuite

Binstances

C4

Dmethods

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'methods' instead of 'instances' for parallel mode.

Setting thread count to a wrong number.

The suite name is ParallelSuite, parallel mode is instances, and thread count is 4.

Practice

1. What is the main benefit of running tests in parallel in a CI environment?

easy

A. It increases the number of test cases by duplicating them.

B. It ensures tests run in a specific order to avoid failures.

C. It reduces the total test execution time by running tests simultaneously.

D. It disables tests that are flaky to improve stability.

Solution

1. Step 1: Understand parallel test execution

   Parallel execution means running multiple tests at the same time instead of one after another.

2. Step 2: Identify the benefit in CI

   Running tests simultaneously saves time, making the feedback faster in continuous integration.

3. Final Answer:

   It reduces the total test execution time by running tests simultaneously. -> Option C

4. Quick Check:

   Parallel tests = faster execution [OK]

Hint: Parallel tests run together to save time [OK]

Common Mistakes:

• Thinking parallel means tests run in order
• Believing parallel increases test count
• Assuming parallel disables flaky tests

2. Which TestNG XML attribute correctly enables parallel test execution?

easy

A.

B.

C.

D.

Solution

1. Step 1: Recall TestNG XML syntax for parallelism

   The correct attribute to enable parallel execution is 'parallel' with values like 'methods', 'tests', or 'classes'.

2. Step 2: Identify correct thread count attribute

   The attribute 'thread-count' sets how many threads run in parallel.

3. Final Answer:

   <suite parallel="methods" thread-count="4"> -> Option B

4. Quick Check:

   parallel + thread-count = correct syntax [OK]

Hint: Use parallel and thread-count attributes in TestNG XML [OK]

Common Mistakes:

• Using non-existent attributes like runParallel
• Confusing thread-count with threads
• Using order="sequential" disables parallelism

3. Given this TestNG XML snippet, what is the maximum number of tests running at the same time?

<suite name="Suite" parallel="tests" thread-count="3">
  <test name="Test1">...</test>
  <test name="Test2">...</test>
  <test name="Test3">...</test>
  <test name="Test4">...</test>
</suite>

medium

A. 3 tests run simultaneously

B. 4 tests run simultaneously

C. 1 test runs at a time

D. 2 tests run simultaneously

Solution

1. Step 1: Understand parallel="tests" meaning

   Setting parallel="tests" means TestNG runs multiple <test> tags at the same time.

2. Step 2: Check thread-count value

   thread-count="3" limits the number of simultaneous threads to 3, so max 3 tests run together.

3. Final Answer:

   3 tests run simultaneously -> Option A

4. Quick Check:

   parallel=tests + thread-count=3 means 3 parallel tests [OK]

Hint: thread-count limits max parallel tests [OK]

Common Mistakes:

• Assuming all tests run at once ignoring thread-count
• Confusing parallel="methods" with parallel="tests"
• Thinking thread-count is ignored

4. You configured TestNG with parallel="methods" and thread-count="2". Your tests share a static WebDriver instance. What problem will most likely occur?

medium

A. Tests will fail due to WebDriver conflicts from shared instance.

B. Tests will run faster without any issues.

C. Tests will run sequentially ignoring parallel settings.

D. Tests will create multiple WebDriver instances automatically.

Solution

1. Step 1: Understand parallel methods with shared static WebDriver

   Parallel methods run at the same time, but sharing a static WebDriver means all tests use the same browser instance.

2. Step 2: Identify concurrency issues

   Sharing one WebDriver causes conflicts like commands overlapping, leading to test failures.

3. Final Answer:

   Tests will fail due to WebDriver conflicts from shared instance. -> Option A

4. Quick Check:

   Shared static WebDriver + parallel = conflicts [OK]

Hint: Avoid shared static WebDriver in parallel tests [OK]

Common Mistakes:

• Assuming shared WebDriver works fine in parallel
• Thinking parallel disables shared resource conflicts
• Believing TestNG creates separate WebDriver automatically

5. You want to run your Selenium tests in parallel in CI using TestNG. Your suite has 5 test classes, each with 3 test methods. You want to run all methods in parallel but limit total threads to 6. Which TestNG XML configuration is correct?

hard

A.

B.

C.

D.

Solution

1. Step 1: Identify parallel="methods" for running all test methods in parallel

   To run all methods in parallel, use parallel="methods" in the suite tag.

2. Step 2: Set thread-count="6" to limit total threads

   thread-count="6" limits the number of simultaneous threads to 6, matching the requirement.

3. Step 3: Confirm classes are inside a single <test> tag

   All classes are grouped under one <test> tag, so methods from all classes run in parallel within the thread limit.

4. Final Answer:

   <suite parallel="methods" thread-count="6"> -> Option D

5. Quick Check:

   parallel="methods" + thread-count="6" + single <test> [OK]

Hint: Use parallel="methods" with thread-count to control concurrency [OK]

Common Mistakes:

• Using parallel="classes" runs classes in parallel, not methods
• Using thread-count too high ignores limit
• Splitting classes into multiple tests changes parallel behavior