Class TestUtils

java.lang.Object

org.apache.kafka.common.test.TestUtils

public class TestUtils
extends Object

Helper functions for writing unit tests.

This class is public because test-common-runtime is packaged as a main source set library JAR — not a test source set — so that other modules (e.g. k2-core-integration, k2proxy/core) can depend on it for shared test infrastructure like JUnit extensions. Classes in other packages within this module (e.g. org.apache.kafka.common.test.junit.ClusterTestExtensions) need access to utilities like waitForCondition(Supplier, String), and Java package-private visibility does not extend to other packages regardless of shared naming prefix. The similar org.apache.kafka.test.TestUtils in clients/src/test/ cannot be used here because main source sets cannot depend on test source sets.

Field Summary

Fields

Modifier and Type	Field	Description
static final String	DIGITS
static final String	LETTERS
static final String	LETTERS_AND_DIGITS
static final Random	SEEDED_RANDOM

Constructor Summary

Constructors

Constructor	Description
TestUtils()

Method Summary

Modifier and Type	Method	Description
static String	randomString(int len)	Generate a random string of letters and digits of the given length
static File	tempFile()	Create an empty file in the default temporary-file directory, using `kafka` as the prefix and `tmp` as the suffix to generate its name.
static void	waitForCondition(Supplier<Boolean> testCondition, long maxWaitMs, String conditionDetails)	Wait for condition to be met for at most maxWaitMs and throw assertion failure otherwise.
static void	waitForCondition(Supplier<Boolean> testCondition, long maxWaitMs, Supplier<String> conditionDetails)	Wait for condition to be met for at most maxWaitMs and throw assertion failure otherwise.
static void	waitForCondition(Supplier<Boolean> testCondition, String conditionDetails)	uses default value of 15 seconds for timeout

Methods inherited from class Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

SEEDED_RANDOM

public static final Random SEEDED_RANDOM

LETTERS

public static final String LETTERS

See Also:

• Constant Field Values

DIGITS

public static final String DIGITS

See Also:

• Constant Field Values

LETTERS_AND_DIGITS

public static final String LETTERS_AND_DIGITS

See Also:

• Constant Field Values

Constructor Details

TestUtils

public TestUtils()

Method Details

tempFile

public static File tempFile()
                     throws IOException

Create an empty file in the default temporary-file directory, using `kafka` as the prefix and `tmp` as the suffix to generate its name.

Throws:

IOException

randomString

public static String randomString(int len)

Generate a random string of letters and digits of the given length

Parameters:

len - The length of the string

Returns:

The random string

waitForCondition

public static void waitForCondition(Supplier<Boolean> testCondition,
 String conditionDetails)
                             throws InterruptedException

uses default value of 15 seconds for timeout

Throws:

InterruptedException

waitForCondition

public static void waitForCondition(Supplier<Boolean> testCondition,
 long maxWaitMs,
 Supplier<String> conditionDetails)
                             throws InterruptedException

Wait for condition to be met for at most maxWaitMs and throw assertion failure otherwise. This should be used instead of Thread.sleep whenever possible as it allows a longer timeout to be used without unnecessarily increasing test time (as the condition is checked frequently). The longer timeout is needed to avoid transient failures due to slow or overloaded machines.

Throws:

InterruptedException

waitForCondition

public static void waitForCondition(Supplier<Boolean> testCondition,
 long maxWaitMs,
 String conditionDetails)
                             throws InterruptedException

Wait for condition to be met for at most maxWaitMs and throw assertion failure otherwise. This should be used instead of Thread.sleep whenever possible as it allows a longer timeout to be used without unnecessarily increasing test time (as the condition is checked frequently). The longer timeout is needed to avoid transient failures due to slow or overloaded machines.

Throws:

InterruptedException