These methods are to verify that an expected list of strings matches an actual list of strings, while providing flexible matching capabilities that include support for regular expressions and fast-forward markers.

public static void assertLinesMatch(List<String> expectedLines, List<String> actualLines)

Example

package com.logicbig.example;

import org.junit.jupiter.api.Test;

import java.util.Arrays;
import java.util.List;

import static org.junit.jupiter.api.Assertions.assertLinesMatch;

class AssertLinesMatchExampleTest {

  @Test
  void exactMatch() {
      List<String> expected = Arrays.asList(
              "Hello",
              "World"
      );

      List<String> actual = Arrays.asList(
              "Hello",
              "World"
      );

      assertLinesMatch(expected, actual);
  }

  @Test
  void regexMatch() {
      List<String> expected = Arrays.asList(
              "User: .*",     // regex match for whole line
              "Age: \\d+"     // regex for digits
      );

      List<String> actual = Arrays.asList(
          "User: Alice",
          "Age: 30"
      );

      assertLinesMatch(expected, actual);
  }

  @Test
  void mixedLiteralAndRegex() {
      List<String> expected = Arrays.asList(
              "START",
              "Value: \\d+",
              "END"
      );

      List<String> actual = Arrays.asList(
              "START",
              "Value: 42",
              "END"
      );

      assertLinesMatch(expected, actual);
  }

  @Test
  void testAssertLinesMatchWithFastForward() {
      List<String> expected = Arrays.asList(
              "Start of log",
              ">>>>", // Fast-forward marker to skip a single line
              "Important value: \\d+", // Regex to match the next line
              ">> stacktrace >>", // Fast-forward marker to skip multiple lines
              "End of log"
      );

      List<String> actual = Arrays.asList(
              "Start of log",
              "This line is skipped by the first marker",
              "Important value: 42", // Matches the regex in expected
              "Here is the first line of the stacktrace...",
              "And the second line...",
              "And the third...",
              "End of log" // Matches the final expected line
      );

      // The assertion passes because the markers handle the mismatches
      assertLinesMatch(expected, actual);
  }
}

mvn test -Dtest=AssertLinesMatchExampleTest

Output

D:\example-projects\junit-5\junit-5-assertions\junit-5-asserting-lines-match>mvn test -Dtest=AssertLinesMatchExampleTest
[INFO] Scanning for projects...
[INFO] 
[INFO] ---------< com.logicbig.example:junit-5-asserting-lines-match >---------
[INFO] Building junit-5-asserting-lines-match 1.0-SNAPSHOT
[INFO]   from pom.xml
[INFO] --------------------------------[ jar ]---------------------------------
[INFO] 
[INFO] --- resources:3.3.1:resources (default-resources) @ junit-5-asserting-lines-match ---
[WARNING] Using platform encoding (UTF-8 actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory D:\example-projects\junit-5\junit-5-assertions\junit-5-asserting-lines-match\src\main\resources
[INFO] 
[INFO] --- compiler:3.14.1:compile (default-compile) @ junit-5-asserting-lines-match ---
[INFO] Nothing to compile - all classes are up to date.
[INFO] 
[INFO] --- resources:3.3.1:testResources (default-testResources) @ junit-5-asserting-lines-match ---
[WARNING] Using platform encoding (UTF-8 actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory D:\example-projects\junit-5\junit-5-assertions\junit-5-asserting-lines-match\src\test\resources
[INFO] 
[INFO] --- compiler:3.14.1:testCompile (default-testCompile) @ junit-5-asserting-lines-match ---
[INFO] Nothing to compile - all classes are up to date.
[INFO] 
[INFO] --- surefire:3.2.5:test (default-test) @ junit-5-asserting-lines-match ---
[INFO] Using auto detected provider org.apache.maven.surefire.junitplatform.JUnitPlatformProvider
[INFO] 
[INFO] -------------------------------------------------------
[INFO]  T E S T S
[INFO] -------------------------------------------------------
[INFO] Running com.logicbig.example.AssertLinesMatchExampleTest
[INFO] Tests run: 4, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.041 s -- in com.logicbig.example.AssertLinesMatchExampleTest
[INFO] 
[INFO] Results:
[INFO] 
[INFO] Tests run: 4, Failures: 0, Errors: 0, Skipped: 0
[INFO] 
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  2.493 s
[INFO] Finished at: 2025-12-01T12:38:40+08:00
[INFO] ------------------------------------------------------------------------

Example Project

Dependencies and Technologies Used:

• junit-jupiter-engine 6.0.1 (Module "junit-jupiter-engine" of JUnit)
   Version Compatibility: 5.0.0 - 6.0.1Version List
  ×

  Version compatibilities of junit-jupiter-engine with this example:

  • 5.0.0
  • 5.0.1
  • 5.0.2
  • 5.0.3
  • 5.1.0
  • 5.1.1
  • 5.2.0
  • 5.3.0
  • 5.3.1
  • 5.3.2
  • 5.4.0
  • 5.4.1
  • 5.4.2
  • 5.5.0
  • 5.5.1
  • 5.5.2
  • 5.6.0
  • 5.6.1
  • 5.6.2
  • 5.6.3
  • 5.7.0
  • 5.7.1
  • 5.7.2
  • 5.8.0
  • 5.8.1
  • 5.8.2
  • 5.9.0
  • 5.9.1
  • 5.9.2
  • 5.9.3
  • 5.10.0
  • 5.10.1
  • 5.10.2
  • 5.10.3
  • 5.10.4
  • 5.10.5
  • 5.11.0
  • 5.11.1
  • 5.11.2
  • 5.11.3
  • 5.11.4
  • 5.12.0
  • 5.12.1
  • 5.12.2
  • 5.13.0
  • 5.13.1
  • 5.13.2
  • 5.13.3
  • 5.13.4
  • 5.14.0
  • 5.14.1
  • 6.0.0
  • 6.0.1

  Versions in green have been tested.

• JDK 25
• Maven 3.9.11