[ML] Get ML filters size should default to 100

When get filters is called without setting the `size`
paramter only up to 10 filters are returned. However,
100 filters should be returned. This commit fixes this
and adds an integ test to guard it.

It seems this was accidentally broken in elastic#39976.

Closes elastic#54206

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ml/action/GetFiltersAction.java

@@ -36,7 +36,7 @@ public static class Request extends AbstractGetResourcesRequest {
 
         public Request() {
             // Put our own defaults for backwards compatibility
-            super(null, null, true);
+            super(null, PageParams.defaultParams(), true);
         }
 
         public Request(StreamInput in) throws IOException {

x-pack/plugin/ml/qa/native-multi-node-tests/src/test/java/org/elasticsearch/xpack/ml/integration/MlFiltersIT.java

@@ -0,0 +1,31 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+
+package org.elasticsearch.xpack.ml.integration;
+
+import org.elasticsearch.xpack.core.ml.action.GetFiltersAction;
+import org.elasticsearch.xpack.core.ml.job.config.MlFilter;
+
+import static org.hamcrest.Matchers.equalTo;
+
+public class MlFiltersIT extends MlNativeIntegTestCase {
+
+    @Override
+    protected void cleanUpResources() {
+        // nothing to clean
+    }
+
+    public void testGetFilters_ShouldReturnUpTo100ByDefault() {
+        int filtersCount = randomIntBetween(11, 100);
+        for (int i = 0; i < filtersCount; i++) {
+            putMlFilter(MlFilter.builder("filter-" + i).setItems("item-" + i).build());
+        }
+
+        GetFiltersAction.Response filters = getMlFilters();
+        assertThat((int) filters.getFilters().count(), equalTo(filtersCount));
+        assertThat(filters.getFilters().results().size(), equalTo(filtersCount));
+    }
+}

x-pack/plugin/ml/qa/native-multi-node-tests/src/test/java/org/elasticsearch/xpack/ml/integration/MlNativeAutodetectIntegTestCase.java

@@ -353,10 +353,6 @@ protected List<Forecast> getForecasts(String jobId, ForecastRequestStats forecas
         return forecasts;
     }
 
-    protected PutFilterAction.Response putMlFilter(MlFilter filter) {
-        return client().execute(PutFilterAction.INSTANCE, new PutFilterAction.Request(filter)).actionGet();
-    }
-
     protected PutCalendarAction.Response putCalendar(String calendarId, List<String> jobIds, String description) {
         PutCalendarAction.Request request = new PutCalendarAction.Request(new Calendar(calendarId, jobIds, description));
         return client().execute(PutCalendarAction.INSTANCE, request).actionGet();

x-pack/plugin/ml/qa/native-multi-node-tests/src/test/java/org/elasticsearch/xpack/ml/integration/MlNativeIntegTestCase.java

@@ -32,12 +32,15 @@
 import org.elasticsearch.xpack.core.ml.MlMetadata;
 import org.elasticsearch.xpack.core.ml.MlTasks;
 import org.elasticsearch.xpack.core.ml.action.DeleteExpiredDataAction;
+import org.elasticsearch.xpack.core.ml.action.GetFiltersAction;
 import org.elasticsearch.xpack.core.ml.action.OpenJobAction;
+import org.elasticsearch.xpack.core.ml.action.PutFilterAction;
 import org.elasticsearch.xpack.core.ml.action.StartDataFrameAnalyticsAction;
 import org.elasticsearch.xpack.core.ml.action.StartDatafeedAction;
 import org.elasticsearch.xpack.core.ml.datafeed.DatafeedState;
 import org.elasticsearch.xpack.core.ml.dataframe.DataFrameAnalyticsTaskState;
 import org.elasticsearch.xpack.core.ml.job.config.JobTaskState;
+import org.elasticsearch.xpack.core.ml.job.config.MlFilter;
 import org.elasticsearch.xpack.core.security.SecurityField;
 import org.elasticsearch.xpack.core.security.authc.TokenMetaData;
 import org.elasticsearch.xpack.ilm.IndexLifecycle;
@@ -161,6 +164,14 @@ protected DeleteExpiredDataAction.Response deleteExpiredData() throws Exception
         return response;
     }
 
+    protected PutFilterAction.Response putMlFilter(MlFilter filter) {
+        return client().execute(PutFilterAction.INSTANCE, new PutFilterAction.Request(filter)).actionGet();
+    }
+
+    protected GetFiltersAction.Response getMlFilters() {
+        return client().execute(GetFiltersAction.INSTANCE, new GetFiltersAction.Request()).actionGet();
+    }
+
     @Override
     protected void ensureClusterStateConsistency() throws IOException {
         if (cluster() != null && cluster().size() > 0) {