Using maven and surefire? This script will help you figure out which tests are slow.

sortTestsByTimeTaken.sh

#!/bin/bash

# This script goes through tests results in `target/surefire-reports` and sorts the results by the
# amount of time they took. This is helpful to identify slow tests.

set -e

# Make sure the surefire folder exists
if [ ! -d "target/surefire-reports" ]; then
	echo "The folder 'target/surefire-reports' doesn't exists. Please run tests before using this script."
	exit 1
fi

# Go through the surefire test reports and sort tests by time taken. Source for this snippet:
# https://stackoverflow.com/questions/45854277/execution-time-of-tests-in-unit-test-class-via-maven-surefire-report-in-a-single/45859700#45859700
grep -h testcase target/surefire-reports/TEST-*.xml |
    awk -F '"' '{print $4 "#" $2 "() - " $6 "ms" }' |
      sort -rn -k 3