Order of execution of tests in TestNG

Question

How to customize the order of execution of tests in TestNG?

For example:

public class Test1 {
  @Test
  public void test1() {
      System.out.println("test1");
  }

  @Test
  public void test2() {
      System.out.println("test2");
  }

  @Test
  public void test3() {
      System.out.println("test3");
  }
}

In the above suite, the order of execution of tests is arbitrary. For one execution the output may be:

test1
test3
test2

How do I execute the tests in the order in which they've been written?

Answer 1

This will work.

@Test(priority=1)
public void Test1() {

}

@Test(priority=2)
public void Test2() {

}

@Test(priority=3)
public void Test3() {

}

priority encourages execution order but does not guarantee the previous priority level has completed. test3 could start before test2 completes. If a guarantee is needed, then declare a dependency.

Unlike the solutions which declare dependencies, tests which use priority will execute even if one test fails. This problem with dependencies can be worked around with @Test(...alwaysRun = true...) according to documentation.