Sample for https://stackoverflow.com/questions/48343413/pass-parameter-to-gradle

build.gradle

apply plugin: 'java'
apply plugin: 'maven'

group = 'com.rationaleemotions'
version = '1.0-SNAPSHOT'

description = """gradle-playground"""

sourceCompatibility = 1.8
targetCompatibility = 1.8
tasks.withType(JavaCompile) {
    options.encoding = 'UTF-8'
}

repositories {

    maven { url "http://jcenter.bintray.com" }
    maven { url "http://repo.maven.apache.org/maven2" }
}
dependencies {
    compile group: 'org.testng', name: 'testng', version: '6.13.1'
    compile group: 'org.seleniumhq.selenium', name: 'selenium-java', version: '3.8.1'
}

test {
    useTestNG() {
        suites "src/test/resources/testng.xml"
    }
    systemProperties(System.getProperties())
    testLogging.showStandardStreams = true
}

console output.txt

08:32 $ gradle clean test -Durl="http://the-internet.herokuapp.com/"

> Task :test

Gradle Test Executor 9 STANDARD_OUT
    ...
    ... TestNG 6.13.1 by Cédric Beust (cedric@beust.com)
    ...


Sample_Suite > Sample_Test > com.rationaleemotions.SampleTest STANDARD_ERROR
    Starting ChromeDriver 2.35.528157 (4429ca2590d6988c0745c24c8858745aaaec01ef) on port 12943
    Only local connections are allowed.
    Jan 21, 2018 8:32:58 AM org.openqa.selenium.remote.ProtocolHandshake createSession
    INFO: Detected dialect: OSS

Sample_Suite > Sample_Test > com.rationaleemotions.SampleTest.testMethod STANDARD_ERROR
    URL = http://the-internet.herokuapp.com/
    Page Title :The Internet


BUILD SUCCESSFUL in 6s
5 actionable tasks: 5 executed

folderstructure.txt

08:33 $ tree src/
src/
├── main
│   └── java
│       └── com
│           └── rationaleemotions
│               └── App.java
└── test
    ├── java
    │   └── com
    │       └── rationaleemotions
    │           └── SampleTest.java
    └── resources
        └── testng.xml

9 directories, 3 files

SampleTest.java

package com.rationaleemotions;

import org.openqa.selenium.chrome.ChromeDriver;
import org.openqa.selenium.remote.RemoteWebDriver;
import org.testng.Assert;
import org.testng.annotations.AfterClass;
import org.testng.annotations.BeforeClass;
import org.testng.annotations.Test;

public class SampleTest {
    private RemoteWebDriver driver;

    @BeforeClass
    public void beforeClass() {
        driver = new ChromeDriver();
    }

    @Test
    public void testMethod() {
        String url = System.getProperty("url");
        Assert.assertNotNull(url, "URL should not have been a null value");
        System.err.println("URL = " + url);
        driver.get(url);
        System.err.println("Page Title :" + driver.getTitle());
    }

    @AfterClass
    public void afterClass() {
        driver.quit();
    }
}

testng.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE suite SYSTEM "http://testng.org/testng-1.0.dtd">
<suite name="Sample_Suite" parallel="false" verbose="2">
    <test name="Sample_Test" verbose="2">
        <classes>
            <class name="com.rationaleemotions.SampleTest"/>
        </classes>
    </test>
</suite>