unable to set environment variable in jenkinsfile - jenkins

Question

I am trying to set an environment variable with name "TEST_CONFIG_ROOT" in my Jenkins pipeline, I am referring to examples here:
https://jenkins.io/doc/book/pipeline/jenkinsfile/#working-with-the-environment
But, When I am executing my test, it appears that env variable is not set, because my test still complains that it did not get the value of the variable "TEST_CONFIG_ROOT" which it was supposed to get from env.
Please see my jenkinsFile below:
node('node1'){
def buildInput;
echo 'Deploying my build'
if(!params.buildName) {
buildInput = input(
id: 'userInput', message: 'What is the build name?', parameters: [
[$class: 'StringParameterDefinition', defaultValue: 'abcd-1', description: 'Environment', name: 'buildName']
])
}
buildToUse = params.buildName ? params.buildName : buildInput;
echo ("Env: "+buildToUse);
if ( "${params.buildParam}" == 'prequal' || !params.buildParam ){
stage('Prequal') {
}
}
node('nodename'){
if ( "${params.buildParam}" == 'test' || !params.buildParam ){
withMaven(
maven: 'M2Slave',
mavenSettingsConfig: 'MavenSettingsXML',
mavenLocalRepo: '${HOME}/.m2/repository') {
stage('Test') {
echo 'Testing my build'
echo " my work space is ${env.WORKSPACE}"
checkout scm
environment {
TEST_CONFIG_ROOT = '${env.WORKSPACE}/testsE2e/src/main/resources'
}
dir ( 'testsE2e'){
sh 'mvn clean verify surefire-report:report surefire-report:failsafe-report-only -Dtestngxml=testng.xml -Dhttp.proxyHost=proxy02.com -Dhttp.proxyPort=8080 -Dhttps.proxyHost=proxy02.com -Dhttps.proxyPort=8080 -Djavax.xml.accessExternalSchema=all'
}
}
}
}
}
}
I also tried executing the export command using the shell script as below, but this is also not helping.
echo " my work space is ${env.WORKSPACE}"
sh 'export TEST_CONFIG_ROOT="${WORKSPACE}/testsE2e/src/main/resources"'
Find below snippet of log when the pipeline job is executed:
[Pipeline] echo
my work space is /usr/home/nodename/Jenkins/workspace/workspace/someName-RCZ4A4MA3GRP4PSVYT4HTVVIKU4J7TW2667CKTZU22CHR2CBEM5Q
[Pipeline] dir
Running in /usr/home/nodename/Jenkins/workspace/workspace/someName-RCZ4A4MA3GRP4PSVYT4HTVVIKU4J7TW2667CKTZU22CHR2CBEM5Q/testsE2e
[Pipeline] {
[Pipeline] sh
[testsE2e] Running shell script
+ mvn clean verify surefire-report:report surefire-report:failsafe-report-only -Dtestngxml=testng.xml -Dhttp.proxyHost=proxy02.com -Dhttp.proxyPort=8080 -Dhttps.proxyHost=proxy02.com -Dhttps.proxyPort=8080 -Djavax.xml.accessExternalSchema=all
----- withMaven Wrapper script -----
Picked up JAVA_TOOL_OPTIONS: -Dmaven.ext.class.path="/usr/home/nodename/Jenkins/workspace/workspace/someName-RCZ4A4MA3GRP4PSVYT4HTVVIKU4J7TW2667CKTZU22CHR2CBEM5Q#tmp/withMaven00e87287/pipeline-maven-spy.jar" -Dorg.jenkinsci.plugins.pipeline.maven.reportsFolder="/usr/home/nodename/Jenkins/workspace/workspace/someName-RCZ4A4MA3GRP4PSVYT4HTVVIKU4J7TW2667CKTZU22CHR2CBEM5Q#tmp/withMaven00e87287"
Apache Maven 3.3.9 (bb52d8502b132ec0a5a3f4c09453c07478323dc5; 2015-11-10T08:41:47-08:00)
Maven home: /opt/maven/apache-maven-3.3.9
Java version: 1.8.0_111, vendor: Oracle Corporation
Java home: /opt/oracle/jdk1.8.0_111/jre
Default locale: en_US, platform encoding: UTF-8
OS name: "linux", version: "2.6.32-573.7.1.el6.x86_64", arch: "amd64", family: "unix"
[jenkins-maven-event-spy] INFO generate /usr/home/nodename/Jenkins/workspace/workspace/someName-RCZ4A4MA3GRP4PSVYT4HTVVIKU4J7TW2667CKTZU22CHR2CBEM5Q#tmp/withMaven00e87287/maven-spy-20170924-225639-49.log ...
[INFO] Scanning for projects...

Answer 1

I would say you're mixing up declarative pipelines with scripted ones (see Pipeline Syntax in the docs).
The following code snippet belongs to declarative ones, but you have a scripted one:
environment {
TEST_CONFIG_ROOT = "${env.WORKSPACE}/testsE2e/src/main/resources"
}
With scripted pipelines, it's actually a bit easier:
env.TEST_CONFIG_ROOT = "${env.WORKSPACE}/testsE2e/src/main/resources"

Answer 2

So, this is what worked in my case, just mentioning for others reference too.
withEnv(["TEST_CONFIG_ROOT=${env.WORKSPACE}/testsE2e/src/main/resources"]) {
dir ( 'testsE2e'){
sh 'mvn clean verify surefire-report:report surefire-report:failsafe-report-only -Dtestngxml=testng.xml -Dhttp.proxyHost=proxy02.com -Dhttp.proxyPort=8080 -Dhttps.proxyHost=proxy02.com -Dhttps.proxyPort=8080 -Djavax.xml.accessExternalSchema=all'
}
}