add tests to StringStatsAggregatorTests (#54033)

This adds tests for supported ValuesSourceTypes, unmapped fields,
scripting, and the missing param.

Also changes the supported type tests to catch AssertionError, which is
what string stats produces on some unsupported field types. And when
this test fails it now lists the original exception/assertion error as a
cause

test/framework/src/main/java/org/elasticsearch/search/aggregations/AggregatorTestCase.java

@@ -683,10 +683,11 @@ public abstract class AggregatorTestCase extends ESTestCase {
                             fail("Aggregator [" + aggregationBuilder.getType() + "] should not support field type ["
                                 + fieldType.typeName() + "] but executing against the field did not throw an exception");
                         }
-                    } catch (Exception e) {
+                    } catch (Exception | AssertionError e) {
                         if (supportedVSTypes.contains(vst) && unsupportedMappedFieldTypes.contains(fieldType.typeName()) == false) {
-                            fail("Aggregator [" + aggregationBuilder.getType() + "] supports field type ["
-                                + fieldType.typeName() + "] but executing against the field threw an exception: [" + e.getMessage() + "]");
+                            throw new AssertionError("Aggregator [" + aggregationBuilder.getType() + "] supports field type ["
+                                + fieldType.typeName() + "] but executing against the field threw an exception: [" + e.getMessage() + "]",
+                                e);
                         }
                     }
                 }
@@ -706,7 +707,7 @@ public abstract class AggregatorTestCase extends ESTestCase {
         ValuesSourceType vst = fieldType.getValuesSourceType();
         Document doc = new Document();
         String json;
-        
+
         if (vst.equals(CoreValuesSourceType.NUMERIC)) {
             // TODO note: once VS refactor adds DATE/BOOLEAN, this conditional will go away
             long v;

x-pack/plugin/analytics/src/test/java/org/elasticsearch/xpack/analytics/stringstats/StringStatsAggregatorTests.java

@@ -18,24 +18,46 @@ import org.apache.lucene.search.TermInSetQuery;
 import org.apache.lucene.store.Directory;
 import org.apache.lucene.util.BytesRef;
 import org.elasticsearch.common.CheckedConsumer;
+import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.index.mapper.IpFieldMapper;
 import org.elasticsearch.index.mapper.MappedFieldType;
 import org.elasticsearch.index.mapper.NumberFieldMapper;
 import org.elasticsearch.index.mapper.TextFieldMapper;
+import org.elasticsearch.script.MockScriptEngine;
+import org.elasticsearch.script.Script;
+import org.elasticsearch.script.ScriptEngine;
+import org.elasticsearch.script.ScriptModule;
+import org.elasticsearch.script.ScriptService;
+import org.elasticsearch.script.ScriptType;
 import org.elasticsearch.search.aggregations.AggregationBuilder;
 import org.elasticsearch.search.aggregations.AggregatorTestCase;
 import org.elasticsearch.search.aggregations.bucket.terms.Terms;
 import org.elasticsearch.search.aggregations.bucket.terms.TermsAggregationBuilder;
 import org.elasticsearch.search.aggregations.bucket.terms.TermsAggregator;
+import org.elasticsearch.search.aggregations.support.CoreValuesSourceType;
 import org.elasticsearch.search.aggregations.support.ValueType;
+import org.elasticsearch.search.aggregations.support.ValuesSourceType;
+import org.elasticsearch.search.lookup.LeafDocLookup;
 
 import java.io.IOException;
 import java.util.List;
+import java.util.Map;
+import java.util.Set;
 import java.util.function.Consumer;
+import java.util.function.Function;
 
+import static java.util.Collections.emptyMap;
+import static java.util.Collections.emptySet;
 import static java.util.Collections.singleton;
+import static java.util.Collections.singletonList;
+import static java.util.Collections.singletonMap;
+import static java.util.stream.Collectors.toList;
 
 public class StringStatsAggregatorTests extends AggregatorTestCase {
 
+    private static final String VALUE_SCRIPT_NAME = "value_script";
+    private static final String FIELD_SCRIPT_NAME = "field_script";
+
     private void testCase(Query query,
                           CheckedConsumer<RandomIndexWriter, IOException> buildIndex,
                           Consumer<InternalStringStats> verify) throws IOException {
@@ -119,6 +141,32 @@ public class StringStatsAggregatorTests extends AggregatorTestCase {
         }, null);
     }
 
+    public void testMissing() throws IOException {
+        final TextFieldMapper.TextFieldType fieldType = new TextFieldMapper.TextFieldType();
+        fieldType.setName("text");
+        fieldType.setFielddata(true);
+
+        final StringStatsAggregationBuilder aggregationBuilder = new StringStatsAggregationBuilder("_name")
+            .field(fieldType.name())
+            .missing("b");
+
+        testCase(aggregationBuilder, new MatchAllDocsQuery(), iw -> {
+            iw.addDocument(singleton(new TextField(fieldType.name(), "a", Field.Store.NO)));
+            iw.addDocument(emptySet());
+            iw.addDocument(singleton(new TextField(fieldType.name(), "a", Field.Store.NO)));
+            iw.addDocument(emptySet());
+        }, stats -> {
+            assertEquals(4, stats.getCount());
+            assertEquals(1, stats.getMaxLength());
+            assertEquals(1, stats.getMinLength());
+            assertEquals(1.0, stats.getAvgLength(), 0);
+            assertEquals(2, stats.getDistribution().size());
+            assertEquals(0.5, stats.getDistribution().get("a"), 0);
+            assertEquals(0.5, stats.getDistribution().get("b"), 0);
+            assertEquals(1.0, stats.getEntropy(), 0);
+        }, fieldType);
+    }
+
     public void testSingleValuedField() throws IOException {
         testCase(new MatchAllDocsQuery(), iw -> {
             for(int i=0; i < 10; i++) {
@@ -258,4 +306,144 @@ public class StringStatsAggregatorTests extends AggregatorTestCase {
         directory.close();
     }
 
+    public void testValueScriptSingleValuedField() throws IOException {
+        final TextFieldMapper.TextFieldType fieldType = new TextFieldMapper.TextFieldType();
+        fieldType.setName("text");
+        fieldType.setFielddata(true);
+
+        final StringStatsAggregationBuilder aggregationBuilder = new StringStatsAggregationBuilder("_name")
+            .field(fieldType.name())
+            .script(new Script(ScriptType.INLINE, MockScriptEngine.NAME, VALUE_SCRIPT_NAME, emptyMap()));
+
+        testCase(aggregationBuilder, new MatchAllDocsQuery(), iw -> {
+            iw.addDocument(singleton(new TextField(fieldType.name(), "b", Field.Store.NO)));
+            iw.addDocument(singleton(new TextField(fieldType.name(), "b", Field.Store.NO)));
+        }, stats -> {
+            assertEquals(2, stats.getCount());
+            assertEquals(2, stats.getMaxLength());
+            assertEquals(2, stats.getMinLength());
+            assertEquals(2.0, stats.getAvgLength(), 0);
+            assertEquals(2, stats.getDistribution().size());
+            assertEquals(0.5, stats.getDistribution().get("a"), 0);
+            assertEquals(0.5, stats.getDistribution().get("b"), 0);
+            assertEquals(1.0, stats.getEntropy(), 0);
+        }, fieldType);
+    }
+
+    public void testValueScriptMultiValuedField() throws IOException {
+        final TextFieldMapper.TextFieldType fieldType = new TextFieldMapper.TextFieldType();
+        fieldType.setName("text");
+        fieldType.setFielddata(true);
+
+        final StringStatsAggregationBuilder aggregationBuilder = new StringStatsAggregationBuilder("_name")
+            .field(fieldType.name())
+            .script(new Script(ScriptType.INLINE, MockScriptEngine.NAME, VALUE_SCRIPT_NAME, emptyMap()));
+
+        testCase(aggregationBuilder, new MatchAllDocsQuery(), iw -> {
+            iw.addDocument(Set.of(
+                new TextField(fieldType.name(), "b", Field.Store.NO),
+                new TextField(fieldType.name(), "c", Field.Store.NO)
+            ));
+            iw.addDocument(Set.of(
+                new TextField(fieldType.name(), "b", Field.Store.NO),
+                new TextField(fieldType.name(), "c", Field.Store.NO)
+            ));
+        }, stats -> {
+            assertEquals(4, stats.getCount());
+            assertEquals(2, stats.getMaxLength());
+            assertEquals(2, stats.getMinLength());
+            assertEquals(2.0, stats.getAvgLength(), 0);
+            assertEquals(3, stats.getDistribution().size());
+            assertEquals(0.5, stats.getDistribution().get("a"), 0);
+            assertEquals(0.25, stats.getDistribution().get("b"), 0);
+            assertEquals(0.25, stats.getDistribution().get("c"), 0);
+            assertEquals(1.5, stats.getEntropy(), 0);
+        }, fieldType);
+    }
+
+    public void testFieldScriptSingleValuedField() throws IOException {
+        final TextFieldMapper.TextFieldType fieldType = new TextFieldMapper.TextFieldType();
+        fieldType.setName("text");
+        fieldType.setFielddata(true);
+
+        final StringStatsAggregationBuilder aggregationBuilder = new StringStatsAggregationBuilder("_name")
+            .script(new Script(ScriptType.INLINE, MockScriptEngine.NAME, FIELD_SCRIPT_NAME, singletonMap("field", fieldType.name())));
+
+        testCase(aggregationBuilder, new MatchAllDocsQuery(), iw -> {
+            iw.addDocument(singleton(new TextField(fieldType.name(), "b", Field.Store.NO)));
+            iw.addDocument(singleton(new TextField(fieldType.name(), "b", Field.Store.NO)));
+        }, stats -> {
+            assertEquals(2, stats.getCount());
+            assertEquals(2, stats.getMaxLength());
+            assertEquals(2, stats.getMinLength());
+            assertEquals(2.0, stats.getAvgLength(), 0);
+            assertEquals(2, stats.getDistribution().size());
+            assertEquals(0.5, stats.getDistribution().get("a"), 0);
+            assertEquals(0.5, stats.getDistribution().get("b"), 0);
+            assertEquals(1.0, stats.getEntropy(), 0);
+        }, fieldType);
+    }
+
+    public void testFieldScriptMultiValuedField() throws IOException {
+        final TextFieldMapper.TextFieldType fieldType = new TextFieldMapper.TextFieldType();
+        fieldType.setName("text");
+        fieldType.setFielddata(true);
+
+        final StringStatsAggregationBuilder aggregationBuilder = new StringStatsAggregationBuilder("_name")
+            .script(new Script(ScriptType.INLINE, MockScriptEngine.NAME, FIELD_SCRIPT_NAME, singletonMap("field", fieldType.name())));
+
+        testCase(aggregationBuilder, new MatchAllDocsQuery(), iw -> {
+            iw.addDocument(Set.of(
+                new TextField(fieldType.name(), "b", Field.Store.NO),
+                new TextField(fieldType.name(), "c", Field.Store.NO)
+            ));
+            iw.addDocument(Set.of(
+                new TextField(fieldType.name(), "b", Field.Store.NO),
+                new TextField(fieldType.name(), "c", Field.Store.NO)
+            ));
+        }, stats -> {
+            assertEquals(4, stats.getCount());
+            assertEquals(2, stats.getMaxLength());
+            assertEquals(2, stats.getMinLength());
+            assertEquals(2.0, stats.getAvgLength(), 0);
+            assertEquals(3, stats.getDistribution().size());
+            assertEquals(0.5, stats.getDistribution().get("a"), 0);
+            assertEquals(0.25, stats.getDistribution().get("b"), 0);
+            assertEquals(0.25, stats.getDistribution().get("c"), 0);
+            assertEquals(1.5, stats.getEntropy(), 0);
+        }, fieldType);
+    }
+
+    @Override
+    protected AggregationBuilder createAggBuilderForTypeTest(MappedFieldType fieldType, String fieldName) {
+        return new StringStatsAggregationBuilder("_name")
+            .field(fieldName);
+    }
+
+    @Override
+    protected List<ValuesSourceType> getSupportedValuesSourceTypes() {
+        return singletonList(CoreValuesSourceType.BYTES);
+    }
+
+    @Override
+    protected List<String> unsupportedMappedFieldTypes() {
+        return singletonList(IpFieldMapper.CONTENT_TYPE);
+    }
+
+    @Override
+    protected ScriptService getMockScriptService() {
+        final Map<String, Function<Map<String, Object>, Object>> scripts = Map.of(
+            VALUE_SCRIPT_NAME, vars -> "a" + vars.get("_value"),
+            FIELD_SCRIPT_NAME, vars -> {
+                final String fieldName = (String) vars.get("field");
+                final LeafDocLookup lookup = (LeafDocLookup) vars.get("doc");
+                return lookup.get(fieldName).stream()
+                    .map(value -> "a" + value)
+                    .collect(toList());
+            }
+        );
+        final MockScriptEngine engine = new MockScriptEngine(MockScriptEngine.NAME, scripts, emptyMap());
+        final Map<String, ScriptEngine> engines = singletonMap(engine.getType(), engine);
+        return new ScriptService(Settings.EMPTY, engines, ScriptModule.CORE_CONTEXTS);
+    }
 }

x-pack/plugin/src/test/resources/rest-api-spec/test/analytics/string_stats.yml

@@ -0,0 +1,53 @@
+setup:
+  - do:
+      indices.create:
+        index: test
+        body:
+          mappings:
+            properties:
+              value:
+                type: keyword
+  - do:
+      bulk:
+        index: test
+        refresh: true
+        body:
+          - '{"index": {}}'
+          - '{"value": "a"}'
+          - '{"index": {}}'
+          - '{"value": "b"}'
+
+---
+"basic":
+  - do:
+      search:
+        size: 0
+        body:
+          aggs:
+            my_agg:
+              string_stats:
+                field: value
+  - match: { aggregations.my_agg.count: 2 }
+  - match: { aggregations.my_agg.min_length: 1 }
+  - match: { aggregations.my_agg.max_length: 1 }
+  - match: { aggregations.my_agg.avg_length: 1.0 }
+  - match: { aggregations.my_agg.entropy: 1.0 }
+
+---
+"show_distribution":
+  - do:
+      search:
+        size: 0
+        body:
+          aggs:
+            my_agg:
+              string_stats:
+                field: value
+                show_distribution: true
+  - match: { aggregations.my_agg.count: 2 }
+  - match: { aggregations.my_agg.min_length: 1 }
+  - match: { aggregations.my_agg.max_length: 1 }
+  - match: { aggregations.my_agg.avg_length: 1.0 }
+  - match: { aggregations.my_agg.entropy: 1.0 }
+  - match: { aggregations.my_agg.distribution.a: 0.5 }
+  - match: { aggregations.my_agg.distribution.b: 0.5 }