[Java] Re-enable remaining skipped Java test cases
diff --git a/java/test/src/main/java/io/ray/test/ExitActorTest.java b/java/test/src/main/java/io/ray/test/ExitActorTest.java
index a1c40e2ac8a1c..279af55c05e59 100644
--- a/java/test/src/main/java/io/ray/test/ExitActorTest.java
+++ b/java/test/src/main/java/io/ray/test/ExitActorTest.java
@@ -15,9 +15,7 @@
 import org.testng.Assert;
 import org.testng.annotations.Test;
 
-@Test(
-    groups = {"cluster"},
-    enabled = false)
+@Test(groups = {"cluster"})
 public class ExitActorTest extends BaseTest {
 
   private static class ExitingActor {
diff --git a/java/test/src/main/java/io/ray/test/MultiDriverTest.java b/java/test/src/main/java/io/ray/test/MultiDriverTest.java
index 3feb981927c06..9c781f56283f9 100644
--- a/java/test/src/main/java/io/ray/test/MultiDriverTest.java
+++ b/java/test/src/main/java/io/ray/test/MultiDriverTest.java
@@ -17,9 +17,7 @@
 import org.testng.Assert;
 import org.testng.annotations.Test;
 
-@Test(
-    groups = {"cluster"},
-    enabled = false)
+@Test(groups = {"cluster"})
 public class MultiDriverTest extends BaseTest {
 
   private static final int DRIVER_COUNT = 10;
diff --git a/java/test/src/main/java/io/ray/test/PlacementGroupTest.java b/java/test/src/main/java/io/ray/test/PlacementGroupTest.java
index 89d1fab694523..655479bd43f97 100644
--- a/java/test/src/main/java/io/ray/test/PlacementGroupTest.java
+++ b/java/test/src/main/java/io/ray/test/PlacementGroupTest.java
@@ -32,7 +32,7 @@ public int getValue() {
   // It's not comprehensive to test all placement group test cases.
   public void testCreateAndCallActor() {
     PlacementGroup placementGroup = PlacementGroupTestUtils.createSimpleGroup();
-    Assert.assertTrue(placementGroup.wait(10));
+    Assert.assertTrue(placementGroup.wait(60));
     Assert.assertEquals(placementGroup.getName(), "unnamed_group");
 
     // Test creating an actor from a constructor.
@@ -53,8 +53,8 @@ public void testGetPlacementGroup() {
     PlacementGroup secondPlacementGroup =
         PlacementGroupTestUtils.createNameSpecifiedSimpleGroup(
             "CPU", 1, PlacementStrategy.PACK, 1.0, "second_placement_group");
-    Assert.assertTrue(firstPlacementGroup.wait(10));
-    Assert.assertTrue(secondPlacementGroup.wait(10));
+    Assert.assertTrue(firstPlacementGroup.wait(60));
+    Assert.assertTrue(secondPlacementGroup.wait(60));
 
     PlacementGroup firstPlacementGroupRes = Ray.getPlacementGroup((firstPlacementGroup).getId());
     PlacementGroup secondPlacementGroupRes = Ray.getPlacementGroup((secondPlacementGroup).getId());
@@ -83,16 +83,17 @@ public void testGetPlacementGroup() {
     Assert.assertEquals(placementGroupRes.getStrategy(), expectPlacementGroup.getStrategy());
   }
 
-  @Test(
-      groups = {"cluster"},
-      enabled = false)
+  @Test(groups = {"cluster"})
   public void testRemovePlacementGroup() {
-    PlacementGroupTestUtils.createNameSpecifiedSimpleGroup(
-        "CPU", 1, PlacementStrategy.PACK, 1.0, "first_placement_group");
+    PlacementGroup firstPlacementGroup =
+        PlacementGroupTestUtils.createNameSpecifiedSimpleGroup(
+            "CPU", 1, PlacementStrategy.PACK, 1.0, "first_placement_group");
 
     PlacementGroup secondPlacementGroup =
         PlacementGroupTestUtils.createNameSpecifiedSimpleGroup(
             "CPU", 1, PlacementStrategy.PACK, 1.0, "second_placement_group");
+    Assert.assertTrue(firstPlacementGroup.wait(60));
+    Assert.assertTrue(secondPlacementGroup.wait(60));
 
     List<PlacementGroup> allPlacementGroup = Ray.getAllPlacementGroups();
     Assert.assertEquals(allPlacementGroup.size(), 2);
@@ -114,6 +115,7 @@ public void testRemovePlacementGroup() {
 
   public void testCheckBundleIndex() {
     PlacementGroup placementGroup = PlacementGroupTestUtils.createSimpleGroup();
+    Assert.assertTrue(placementGroup.wait(60));
 
     int exceptionCount = 0;
     try {
diff --git a/python/ray/tests/test_placement_group.py b/python/ray/tests/test_placement_group.py
index 024ff6c5557a7..a311189a380f6 100644
--- a/python/ray/tests/test_placement_group.py
+++ b/python/ray/tests/test_placement_group.py
@@ -312,6 +312,7 @@ def test_remove_placement_group(ray_start_cluster):
     # Creating a placement group as soon as it is
     # created should work.
     placement_group = ray.util.placement_group([{"CPU": 2}, {"CPU": 2}])
+    assert placement_group.wait(10)
     ray.util.remove_placement_group(placement_group)
 
     def is_placement_group_removed():
@@ -324,6 +325,7 @@ def is_placement_group_removed():
 
     # # Now let's create a placement group.
     placement_group = ray.util.placement_group([{"CPU": 2}, {"CPU": 2}])
+    assert placement_group.wait(10)
 
     # Create an actor that occupies resources.
     @ray.remote(num_cpus=2)

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## Why are these changes needed?

Re-enable `ExitActorTest`, `MultiDriverTest`. Fix `PlacementGroupTest` (by @clay4444).

One remaining issue: Raylet fails to start occasionally ([CI log](https://travis-ci.com/github/ray-project/ray/jobs/481590843)). The root cause is that the grpc server port of node manager was occupied by another process. This is a known issue (see #8254 and #9615). However the error message is unclear, I'll address it in another PR.

## Related issue number

Closes #13714

## Checks

- [ ] I've run `scripts/format.sh` to lint the changes in this PR.
- [ ] I've included any doc changes needed for https://docs.ray.io/en/master/.
- [ ] I've made sure the tests are passing. Note that there might be a few flaky tests, see the recent failures at https://flakey-tests.ray.io/
- Testing Strategy
   - [ ] Unit tests
   - [ ] Release tests
   - [ ] This PR is not tested :(
