Rest Tests - Support for matching objects in lists

Makes it possible to have a key that points to a list and assert that a
certain object is present in the list. All keys have to be present and
values have to match. The objects in the source list may have additional
fields.

example:
```
  contains:  { 'nodes.$master.plugins': { name: ingest-attachment }  }
```

Backported from elastic#30874 (e8b8d11)

Co-authored-by: Alpar Torok <[email protected]>

Author: tvernum

test/framework/src/main/java/org/elasticsearch/test/rest/yaml/section/ContainsAssertion.java

@@ -0,0 +1,80 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.elasticsearch.test.rest.yaml.section;
+
+import org.apache.logging.log4j.Logger;
+import org.elasticsearch.common.collect.Tuple;
+import org.elasticsearch.common.logging.Loggers;
+import org.elasticsearch.common.xcontent.XContentLocation;
+import org.elasticsearch.common.xcontent.XContentParser;
+
+import java.io.IOException;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+import static org.hamcrest.Matchers.empty;
+import static org.hamcrest.Matchers.is;
+import static org.hamcrest.Matchers.not;
+import static org.junit.Assert.assertThat;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
+
+public class ContainsAssertion extends Assertion {
+    public static ContainsAssertion parse(XContentParser parser) throws IOException {
+        XContentLocation location = parser.getTokenLocation();
+        Tuple<String, Object> stringObjectTuple = ParserUtils.parseTuple(parser);
+        return new ContainsAssertion(location, stringObjectTuple.v1(), stringObjectTuple.v2());
+    }
+
+    private static final Logger logger = Loggers.getLogger(ContainsAssertion.class);
+
+    public ContainsAssertion(XContentLocation location, String field, Object expectedValue) {
+        super(location, field, expectedValue);
+    }
+
+    @Override
+    protected void doAssert(Object actualValue, Object expectedValue) {
+        // add support for matching objects ({a:b}) against list of objects ([ {a:b, c:d} ])
+        if (expectedValue instanceof Map && actualValue instanceof List) {
+            logger.trace("assert that [{}] contains [{}]", actualValue, expectedValue);
+            Map<String, Object> expectedMap = (Map<String, Object>) expectedValue;
+            List<Object> actualList = (List<Object>) actualValue;
+            List<Map<String, Object>> actualValues = actualList.stream()
+                .filter(each -> each instanceof Map)
+                .map((each -> (Map<String, Object>) each))
+                .filter(each -> each.keySet().containsAll(expectedMap.keySet()))
+                .collect(Collectors.toList());
+            assertThat(
+                getField() + " expected to be a list with at least one object that has keys: " +
+                    expectedMap.keySet() + " but it was " + actualList,
+                actualValues,
+                is(not(empty()))
+            );
+            assertTrue(
+                getField() + " expected to be a list with at least on object that matches " + expectedMap +
+                    " but was " + actualValues,
+                actualValues.stream()
+                    .anyMatch(each -> each.entrySet().containsAll(expectedMap.entrySet()))
+            );
+        } else {
+            fail("'contains' only supports checking an object against a list of objects");
+        }
+    }
+}

test/framework/src/main/java/org/elasticsearch/test/rest/yaml/section/ExecutableSection.java

@@ -47,6 +47,7 @@ public interface ExecutableSection {
             new NamedXContentRegistry.Entry(ExecutableSection.class, new ParseField("gte"), GreaterThanEqualToAssertion::parse),
             new NamedXContentRegistry.Entry(ExecutableSection.class, new ParseField("lt"), LessThanAssertion::parse),
             new NamedXContentRegistry.Entry(ExecutableSection.class, new ParseField("lte"), LessThanOrEqualToAssertion::parse),
+            new NamedXContentRegistry.Entry(ExecutableSection.class, new ParseField("contains"), ContainsAssertion::parse),
             new NamedXContentRegistry.Entry(ExecutableSection.class, new ParseField("length"), LengthAssertion::parse)));
 
     /**

test/framework/src/test/java/org/elasticsearch/test/rest/yaml/section/AssertionTests.java

@@ -134,6 +134,22 @@ public void testParseMatchArray() throws Exception {
         assertThat(strings.get(1).toString(), equalTo("test_percolator_2"));
     }
 
+    @SuppressWarnings("unchecked")
+    public void testParseContains() throws Exception {
+        parser = createParser(YamlXContent.yamlXContent,
+            "{testKey: { someKey: someValue } }"
+        );
+
+        ContainsAssertion containsAssertion = ContainsAssertion.parse(parser);
+        assertThat(containsAssertion, notNullValue());
+        assertThat(containsAssertion.getField(), equalTo("testKey"));
+        assertThat(containsAssertion.getExpectedValue(), instanceOf(Map.class));
+        assertThat(
+            ((Map<String, String>) containsAssertion.getExpectedValue()).get("someKey"),
+            equalTo("someValue")
+        );
+    }
+
     @SuppressWarnings("unchecked")
     public void testParseMatchSourceValues() throws Exception {
         parser = createParser(YamlXContent.yamlXContent,