[XPACK] Updates assert_nil to remove deprecation warning

Author: picandocodigo

elasticsearch-xpack/test/unit/graph/explore_test.rb

@@ -29,7 +29,7 @@ class GraphExploreTest < Minitest::Test
             assert_equal 'GET', method
             assert_equal 'my_index/_graph/explore', url
             assert_equal Hash.new, params
-            assert_equal nil, body
+            assert_nil body
             true
           end.returns(FakeResponse.new)
 

elasticsearch-xpack/test/unit/index_lifecycle_management/retry_policy_test.rb

@@ -29,7 +29,7 @@ class XPackIndexLifecycleManagementRetryTest < Minitest::Test
             assert_equal 'POST', method
             assert_equal 'foo/_ilm/retry', url
             assert_equal Hash.new, params
-            assert_equal nil, body
+            assert_nil body
             true
           end.returns(FakeResponse.new)
 

elasticsearch-xpack/test/unit/machine_learning/flush_job_test.rb

@@ -29,7 +29,7 @@ class XPackMlFlushJobTest < Minitest::Test
             assert_equal 'POST', method
             assert_equal "_ml/anomaly_detectors/foo/_flush", url
             assert_equal Hash.new, params
-            assert_equal nil, body
+            assert_nil body
             true
           end.returns(FakeResponse.new)
 

elasticsearch-xpack/test/unit/machine_learning/get_buckets_test.rb

@@ -29,7 +29,7 @@ class XPackMlGetBucketsTest < Minitest::Test
             assert_equal 'GET', method
             assert_equal "_ml/anomaly_detectors/foo/results/buckets", url
             assert_equal Hash.new, params
-            assert_equal nil, body
+            assert_nil body
             true
           end.returns(FakeResponse.new)
 

elasticsearch-xpack/test/unit/machine_learning/get_categories_test.rb

@@ -29,7 +29,7 @@ class XPackMlGetCategoriesTest < Minitest::Test
             assert_equal 'GET', method
             assert_equal "_ml/anomaly_detectors/foo/results/categories", url
             assert_equal Hash.new, params
-            assert_equal nil, body
+            assert_nil body
             true
           end.returns(FakeResponse.new)
 

elasticsearch-xpack/test/unit/machine_learning/get_influencers_test.rb

@@ -29,7 +29,7 @@ class XPackMlGetInfluencersTest < Minitest::Test
             assert_equal 'GET', method
             assert_equal "_ml/anomaly_detectors/foo/results/influencers", url
             assert_equal Hash.new, params
-            assert_equal nil, body
+            assert_nil body
             true
           end.returns(FakeResponse.new)
 

elasticsearch-xpack/test/unit/machine_learning/get_model_snapshots_test.rb

@@ -29,7 +29,7 @@ class XPackMlGetModelSnapshotsTest < Minitest::Test
             assert_equal 'GET', method
             assert_equal "_ml/anomaly_detectors/foo/model_snapshots/bar", url
             assert_equal Hash.new, params
-            assert_equal nil, body
+            assert_nil body
             true
           end.returns(FakeResponse.new)
 

elasticsearch-xpack/test/unit/machine_learning/get_overall_buckets_test.rb

@@ -29,7 +29,7 @@ class XPackMlGetOverallBucketsTest < Minitest::Test
             assert_equal 'GET', method
             assert_equal '_ml/anomaly_detectors/foo/results/overall_buckets', url
             assert_equal Hash.new, params
-            assert_equal nil, body
+            assert_nil body
             true
           end.returns(FakeResponse.new)
 

elasticsearch-xpack/test/unit/machine_learning/get_records_test.rb

@@ -29,7 +29,7 @@ class XPackMlGetRecordsTest < Minitest::Test
             assert_equal 'GET', method
             assert_equal "_ml/anomaly_detectors/foo/results/records", url
             assert_equal Hash.new, params
-            assert_equal nil, body
+            assert_nil body
             true
           end.returns(FakeResponse.new)
 

elasticsearch-xpack/test/unit/machine_learning/revert_model_snapshot_test.rb

@@ -29,7 +29,7 @@ class XPackMlRevertModelSnapshotTest < Minitest::Test
             assert_equal 'POST', method
             assert_equal "_ml/anomaly_detectors/foo/model_snapshots/bar/_revert", url
             assert_equal Hash.new, params
-            assert_equal nil, body
+            assert_nil body
             true
           end.returns(FakeResponse.new)