Mutation testing concept (PIT) in JUnit - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to run a basic PIT mutation test with JUnit.

JUnit

MutationCoverage coverage = new MutationCoverageBuilder().withTestPlugin("[1]")

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Amockito

Btestng

Cspock

Djunit

Attempts:

3 left

💡 Hint

Common Mistakes

Using a plugin name for a different testing framework like TestNG or Spock.

The PIT mutation testing tool integrates with JUnit using the "junit" test plugin.

2fill in blank

medium

Complete the code to specify the target classes for mutation testing.

JUnit

PitStrategy strategy = new PitStrategy().withTargetClasses("[1]")

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Acom.example.*

Bcom.pit.*

Cjava.util.*

Dorg.junit.*

Attempts:

3 left

💡 Hint

Common Mistakes

Targeting external libraries like JUnit or Java standard packages.

Target classes should be your own application packages, e.g., "com.example.*".

3fill in blank

hard

Fix the error in the PIT configuration code to correctly set the mutators.

JUnit

PitStrategy strategy = new PitStrategy().withMutators("[1]")

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Adefault

Ball

CDEFAULTS

Dmutate

Attempts:

3 left

💡 Hint

Common Mistakes

Using lowercase or incorrect mutator names causes configuration errors.

The correct mutator set name in PIT is "DEFAULTS" in uppercase.

4fill in blank

hard

Fill both blanks to configure PIT to exclude test classes and set the output format.

JUnit

PitStrategy strategy = new PitStrategy().withExcludedClasses("[1]*").withOutputFormats("[2]")

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ATest

BHTML

CSpec

DXML

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong patterns for exclusion or unsupported output formats.

Exclude test classes by pattern "Test*" and set output format to "HTML" for readable reports.

5fill in blank

hard

Fill all three blanks to create a mutation test run with PIT using JUnit, targeting your package, and setting mutators.

JUnit

PitStrategy strategy = new PitStrategy().withTestPlugin("[1]")
.withTargetClasses("[2]*")
.withMutators("[3]")

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Ajunit

Bcom.myapp

CDEFAULTS

Dtestng

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing test plugins or using incorrect package names or mutator sets.

This sets PIT to use JUnit tests, target your application package "com.myapp*", and use the default mutators.