TestNG and Selenium - parallel execution issues

Question

I'm having some issues with parallel execution of tests using TestNG + Selenium (Chrome WebDriver). Basically, my tests don't actually appear to be truly executed in parallel.

Trying to achieve: Data being read from an Excel spreadsheet. All test cases in TestSuite.java should execute for every row of data, in separate WebDriver instances - running in parallel. Eg testing 5 separate login/password combinations simultaneously in separate browser windows.

Simplified illustration:

public class TestSuite {
    private String param;

    @DataProvider
    public static Object[][] provider() {
        return new Object[][] {{"1"},{"2"}};
    }

    @Factory(dataProvider = "provider")
    public TestSuite(String data) {
        this.param = data;
        System.out.println(String.format("[Thread: %d] TestSuite (%s)", Thread.currentThread().getId(), param));
        // Can't initialise webdriver instances here, different thread
    }

    @BeforeClass
    public void init() {
        System.out.println(String.format("[Thread: %d] BeforeClass (%s)", Thread.currentThread().getId(), param));
        // This is where I'm retrieving webdriver instances
    }

    @Test
    public void TC_001() {
        System.out.println(String.format("[Thread: %d] TC_001 (%s)", Thread.currentThread().getId(), param));
    }

    @Test
    public void TC_002() {
        System.out.println(String.format("[Thread: %d] TC_002 (%s)", Thread.currentThread().getId(), param));
    }
}

TestNG.xml:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE suite SYSTEM "http://testng.org/testng-1.0.dtd" >
<suite name="Suite" parallel="instances" group-by-instances="true">
  <test name="Test">
    <classes>
      <class name="TestSuite" />
    </classes>
  </test>
</suite>

Output:

[Thread: 1] TestSuite (1)
[Thread: 1] TestSuite (2)
[Thread: 11] BeforeClass (1)
[Thread: 11] TC_001 (1)
[Thread: 11] TC_002 (1)
[Thread: 12] BeforeClass (2)
[Thread: 12] TC_001 (2)
[Thread: 12] TC_002 (2)

The main issue here is that my tests are clearly being executed SEQUENTIALLY. Can anyone explain what I have done wrong - what is the correct approach to achieve the desired outcome that I explained above?

Answer 1

make parallel as methods in TestNG.xml as below

suite name="Suite" parallel="methods" group-by-instances="true"