fix: Fix for #168 - When uniqueItems is true, generate unique array elements

Author: en-milie

src/main/java/com/endava/cats/openapi/OpenAPIModelGeneratorV2.java

@@ -24,20 +24,7 @@
 import java.time.OffsetDateTime;
 import java.time.ZoneId;
 import java.time.format.DateTimeFormatter;
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.Base64;
-import java.util.Collection;
-import java.util.Collections;
-import java.util.Date;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Locale;
-import java.util.Map;
-import java.util.Objects;
-import java.util.Optional;
-import java.util.Random;
-import java.util.Set;
+import java.util.*;
 import java.util.function.Supplier;
 import java.util.stream.Collectors;
 
@@ -545,10 +532,7 @@ private List<Object> resolvePropertyToExamples(String propertyName, Schema prope
         recordRequestSchema(currentProperty, property);
 
         if (CatsModelUtils.isArraySchema(property)) {
-            Schema itemSchema = CatsModelUtils.getSchemaItems(property);
-            List<Object> itemExamples = resolvePropertyToExamples(propertyName + ".items", itemSchema);
-            int arraySize = getArrayLength(property);
-            examples.addAll(itemExamples.stream().map(innerExample -> Collections.nCopies(arraySize, innerExample)).toList());
+            createExamplesArray(propertyName, property, examples);
         } else if (CatsModelUtils.isMapSchema(property)) {
             Map<String, Object> mapExample = new HashMap<>();
             Schema additionalProperties = CatsModelUtils.getAdditionalProperties(property);
@@ -585,6 +569,25 @@ private List<Object> resolvePropertyToExamples(String propertyName, Schema prope
         return examples;
     }
 
+    private void createExamplesArray(String propertyName, Schema property, List<Object> examples) {
+        if (Boolean.TRUE.equals(property.getUniqueItems())) {
+            logger.trace("Creating unique items array for property {}", propertyName);
+            int arraySize = getArrayLength(property);
+            Schema itemSchema = CatsModelUtils.getSchemaItems(property);
+            Set<Object> itemExamples = new HashSet<>();
+           while (itemExamples.size() < arraySize) {
+                Object itemExample = resolvePropertyToExample(propertyName + ".items", itemSchema, false);
+                itemExamples.add(itemExample);
+            }
+            examples.add(itemExamples);
+        } else {
+            Schema itemSchema = CatsModelUtils.getSchemaItems(property);
+            List<Object> itemExamples = resolvePropertyToExamples(propertyName + ".items", itemSchema);
+            int arraySize = getArrayLength(property);
+            examples.addAll(itemExamples.stream().map(innerExample -> Collections.nCopies(arraySize, innerExample)).toList());
+        }
+    }
+
     private void mapDiscriminator(Schema<?> composedSchema, List<Schema> anyOf) {
         if (composedSchema.getDiscriminator() != null) {
             logger.trace("Mapping discriminator for schema {}", composedSchema.getName());
@@ -731,8 +734,17 @@ private <T> Object generateStringValue(String propertyName, Schema<T> propertySc
 
     private <T> Object getEnumOrDefault(Schema<T> propertySchema) {
         List<T> enumValues = propertySchema.getEnum();
+
         if (!CollectionUtils.isEmpty(enumValues)) {
-            return enumValues.stream().filter(Objects::nonNull).findAny().orElse(enumValues.getFirst());
+            List<T> nonNullEnumValues = enumValues.stream()
+                    .filter(Objects::nonNull)
+                    .toList();
+
+            if (!nonNullEnumValues.isEmpty()) {
+                return nonNullEnumValues.get(CatsUtil.random().nextInt(nonNullEnumValues.size()));
+            }
+
+            return enumValues.getFirst(); // fallback if all were null
         }
 
         if (propertySchema.getDefault() != null && useDefaults) {
@@ -791,10 +803,10 @@ private List<Map<String, Object>> combineExampleLists(List<Map<String, Object>>
         return combined;
     }
 
-    private Object resolvePropertyToExample(String propertyName, Schema propertySchema) {
+    private Object resolvePropertyToExample(String propertyName, Schema propertySchema, boolean useExamples) {
         logger.trace("resolvePropertyToExample for property {}", propertyName);
         //examples will take first priority
-        Object example = this.extractExampleFromSchema(propertySchema, examplesFlags.usePropertyExamples());
+        Object example = this.extractExampleFromSchema(propertySchema, useExamples);
         if (example != null) {
             logger.trace("Example set in swagger spec, returning example: '{}'", example);
             return example;
@@ -813,6 +825,10 @@ private Object resolvePropertyToExample(String propertyName, Schema propertySche
         return generateExampleBySchemaType(propertyName, propertySchema);
     }
 
+    private Object resolvePropertyToExample(String propertyName, Schema propertySchema) {
+        return resolvePropertyToExample(propertyName, propertySchema, examplesFlags.usePropertyExamples());
+    }
+
     private <T> Object generateExampleBySchemaType(String propertyName, Schema<T> propertySchema) {
         if (CatsModelUtils.isStringSchema(propertySchema)) {
             return this.getExampleFromStringSchema(propertyName, propertySchema);

src/test/java/com/endava/cats/factory/FuzzingDataFactoryTest.java

@@ -13,6 +13,7 @@
 import com.endava.cats.openapi.OpenAPIModelGeneratorV2;
 import com.endava.cats.util.JsonUtils;
 import com.endava.cats.util.OpenApiUtils;
+import com.fasterxml.jackson.databind.JsonNode;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.node.ObjectNode;
 import com.google.gson.JsonParser;
@@ -39,6 +40,7 @@
 import java.math.BigDecimal;
 import java.nio.file.Files;
 import java.nio.file.Paths;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
@@ -1039,6 +1041,33 @@ void shouldGenerateOpenApi31Specs() throws Exception {
                 "residency");
     }
 
+    @Test
+    void shouldGenerateUniqueValuesWhenUniqueItemsTrue() throws Exception {
+        System.getProperties().setProperty("bind-type", "true");
+        List<FuzzingData> dataList = setupFuzzingData("/pet/findByStatus", "src/test/resources/petstore31.yaml");
+        Assertions.assertThat(dataList).hasSize(1);
+        FuzzingData data = dataList.getFirst();
+        String payload = data.getPayload();
+        ObjectMapper mapper = new ObjectMapper();
+        JsonNode root = mapper.readTree(payload);
+
+        JsonNode statusNode = root.get("status");
+        Assertions.assertThat(statusNode).isNotNull();
+        Assertions.assertThat(statusNode.isArray()).isTrue();
+
+        Set<String> uniqueValues = new HashSet<>();
+        for (JsonNode element : statusNode) {
+            boolean added = uniqueValues.add(element.asText());
+            Assertions.assertThat(added)
+                    .as("Duplicate found: " + element.asText())
+                    .isTrue();
+        }
+
+        Assertions.assertThat(uniqueValues.size())
+                .as("Status array contains duplicate elements.")
+                .isEqualTo(statusNode.size());
+    }
+
     @Test
     void shouldRecordErrorWhenParamRefDoesNotExist() throws Exception {
         List<FuzzingData> dataList = setupFuzzingData("/pet-types", "src/test/resources/petstore.yml");

src/test/resources/petstore31.yaml

@@ -91,6 +91,7 @@ paths:
           deprecated: true
           schema:
             type: array
+            uniqueItems: true
             items:
               type: string
               enum: