Ensure findOne does not set batchSize=1

driver-core/src/test/resources/unified-test-format/crud/findOne.json

@@ -0,0 +1,158 @@
+{
+  "description": "findOne",
+  "schemaVersion": "1.0",
+  "createEntities": [
+    {
+      "client": {
+        "id": "client0",
+        "observeEvents": [
+          "commandStartedEvent"
+        ]
+      }
+    },
+    {
+      "database": {
+        "id": "database0",
+        "client": "client0",
+        "databaseName": "find-tests"
+      }
+    },
+    {
+      "collection": {
+        "id": "collection0",
+        "database": "database0",
+        "collectionName": "coll0"
+      }
+    }
+  ],
+  "initialData": [
+    {
+      "collectionName": "coll0",
+      "databaseName": "find-tests",
+      "documents": [
+        {
+          "_id": 1,
+          "x": 11
+        },
+        {
+          "_id": 2,
+          "x": 22
+        },
+        {
+          "_id": 3,
+          "x": 33
+        },
+        {
+          "_id": 4,
+          "x": 44
+        },
+        {
+          "_id": 5,
+          "x": 55
+        },
+        {
+          "_id": 6,
+          "x": 66
+        }
+      ]
+    }
+  ],
+  "tests": [
+    {
+      "description": "FindOne with filter",
+      "operations": [
+        {
+          "object": "collection0",
+          "name": "findOne",
+          "arguments": {
+            "filter": {
+              "_id": 1
+            }
+          },
+          "expectResult": {
+            "_id": 1,
+            "x": 11
+          }
+        }
+      ],
+      "expectEvents": [
+        {
+          "client": "client0",
+          "events": [
+            {
+              "commandStartedEvent": {
+                "command": {
+                  "find": "coll0",
+                  "filter": {
+                    "_id": 1
+                  },
+                  "batchSize": {
+                    "$$exists": false
+                  },
+                  "limit": 1,
+                  "singleBatch": true
+                },
+                "commandName": "find",
+                "databaseName": "find-tests"
+              }
+            }
+          ]
+        }
+      ]
+    },
+    {
+      "description": "FindOne with filter, sort, and skip",
+      "operations": [
+        {
+          "object": "collection0",
+          "name": "findOne",
+          "arguments": {
+            "filter": {
+              "_id": {
+                "$gt": 2
+              }
+            },
+            "sort": {
+              "_id": 1
+            },
+            "skip": 2
+          },
+          "expectResult": {
+            "_id": 5,
+            "x": 55
+          }
+        }
+      ],
+      "expectEvents": [
+        {
+          "client": "client0",
+          "events": [
+            {
+              "commandStartedEvent": {
+                "command": {
+                  "find": "coll0",
+                  "filter": {
+                    "_id": {
+                      "$gt": 2
+                    }
+                  },
+                  "sort": {
+                    "_id": 1
+                  },
+                  "skip": 2,
+                  "batchSize": {
+                    "$$exists": false
+                  },
+                  "limit": 1,
+                  "singleBatch": true
+                },
+                "commandName": "find",
+                "databaseName": "find-tests"
+              }
+            }
+          ]
+        }
+      ]
+    }
+  ]
+}

driver-kotlin-coroutine/src/integrationTest/kotlin/com/mongodb/kotlin/client/coroutine/UnifiedCrudTest.kt

@@ -24,7 +24,7 @@ internal class UnifiedCrudTest() : UnifiedTest() {
         @JvmStatic
         @Throws(URISyntaxException::class, IOException::class)
         fun data(): Collection<Arguments>? {
-            return getTestData("unified-test-format/crud", true)
+            return getTestData("unified-test-format/crud", true, Language.KOTLIN)
         }
     }
 }

driver-kotlin-coroutine/src/integrationTest/kotlin/com/mongodb/kotlin/client/coroutine/UnifiedTest.kt

@@ -39,4 +39,8 @@ internal abstract class UnifiedTest() : JUnifiedTest() {
     ): ClientEncryption {
         TODO("Not yet implemented - JAVA-4896")
     }
+
+    override fun isReactive(): Boolean = true
+
+    override fun getLanguage(): Language = Language.KOTLIN
 }

driver-kotlin-sync/src/integrationTest/kotlin/com/mongodb/kotlin/client/UnifiedCrudTest.kt

@@ -24,7 +24,7 @@ internal class UnifiedCrudTest() : UnifiedTest() {
         @JvmStatic
         @Throws(URISyntaxException::class, IOException::class)
         fun data(): Collection<Arguments>? {
-            return getTestData("unified-test-format/crud", false)
+            return getTestData("unified-test-format/crud", false, Language.KOTLIN)
         }
     }
 }

driver-kotlin-sync/src/integrationTest/kotlin/com/mongodb/kotlin/client/UnifiedTest.kt

@@ -39,4 +39,6 @@ internal abstract class UnifiedTest() : JUnifiedTest() {
     ): ClientEncryption {
         TODO("Not yet implemented - JAVA-4896")
     }
+
+    override fun getLanguage(): Language = Language.KOTLIN
 }

driver-reactive-streams/src/test/functional/com/mongodb/reactivestreams/client/unified/UnifiedReactiveStreamsTest.java

@@ -101,6 +101,6 @@ protected void postCleanUp(final TestDef testDef) {
 
     @NonNull
     protected static Collection<Arguments> getTestData(final String directory) {
-        return getTestData(directory, true);
+        return getTestData(directory, true, Language.JAVA);
     }
 }

driver-sync/src/test/functional/com/mongodb/client/unified/UnifiedCrudHelper.java

@@ -408,6 +408,11 @@ OperationResult executeFind(final BsonDocument operation) {
         });
     }
 
+    /**
+     * There is no explicit {@code findOne()} method in {@link MongoCollection} class.
+     * Its feature was emulated by {@link FindIterable#first()}, which would close cursor on server
+     * by setting {@code batchSize} and {@code limit} appropriately.
+     */
     OperationResult executeFindOne(final BsonDocument operation) {
         return resultOf(() ->  createFindIterable(operation).first());
     }

driver-sync/src/test/functional/com/mongodb/client/unified/UnifiedSyncTest.java

@@ -51,6 +51,6 @@ protected ClientEncryption createClientEncryption(final MongoClient keyVaultClie
 
     @NonNull
     protected static Collection<Arguments> getTestData(final String directory) {
-        return getTestData(directory, false);
+        return getTestData(directory, false, Language.JAVA);
     }
 }

driver-sync/src/test/functional/com/mongodb/client/unified/UnifiedTest.java

@@ -102,6 +102,10 @@ public abstract class UnifiedTest {
     private static final Set<String> PRESTART_POOL_ASYNC_WORK_MANAGER_FILE_DESCRIPTIONS = Collections.singleton(
             "wait queue timeout errors include details about checked out connections");
 
+    public enum Language {
+        JAVA, KOTLIN, SCALA
+    }
+
     public static final int RETRY_ATTEMPTS = 3;
     public static final int FORCE_FLAKY_ATTEMPTS = 10;
     private static final Set<String> ATTEMPTED_TESTS_TO_HENCEFORTH_IGNORE = new HashSet<>();
@@ -161,15 +165,15 @@ public Entities getEntities() {
     }
 
     @NonNull
-    protected static Collection<Arguments> getTestData(final String directory, final boolean isReactive) {
+    protected static Collection<Arguments> getTestData(final String directory, final boolean isReactive, final Language language) {
         List<Arguments> data = new ArrayList<>();
         for (BsonDocument fileDocument : getTestDocuments("/" + directory + "/")) {
             for (BsonValue cur : fileDocument.getArray("tests")) {
 
                 final BsonDocument testDocument = cur.asDocument();
                 String testDescription = testDocument.getString("description").getValue();
                 String fileDescription = fileDocument.getString("description").getValue();
-                TestDef testDef = testDef(directory, fileDescription, testDescription, isReactive);
+                TestDef testDef = testDef(directory, fileDescription, testDescription, isReactive, language);
                 applyCustomizations(testDef);
 
                 boolean forceFlaky = testDef.wasAssignedModifier(Modifier.FORCE_FLAKY);
@@ -240,7 +244,7 @@ public void setUp(
         rootContext.getAssertionContext().push(ContextElement.ofTest(definition));
         ignoreExtraEvents = false;
         if (directoryName != null && fileDescription != null && testDescription != null) {
-            testDef = testDef(directoryName, fileDescription, testDescription, isReactive());
+            testDef = testDef(directoryName, fileDescription, testDescription, isReactive(), getLanguage());
             applyCustomizations(testDef);
 
             boolean skip = testDef.wasAssignedModifier(Modifier.SKIP);
@@ -329,6 +333,10 @@ protected boolean isReactive() {
         return false;
     }
 
+    protected Language getLanguage() {
+        return Language.JAVA;
+    }
+
     @ParameterizedTest(name = "{0}")
     @MethodSource("data")
     public void shouldPassAllOutcomes(

driver-sync/src/test/functional/com/mongodb/client/unified/UnifiedTestModifications.java

@@ -143,6 +143,10 @@ public static void applyCustomizations(final TestDef def) {
                 .test("crud", "findOneAndDelete-hint-unacknowledged", "Unacknowledged findOneAndDelete with hint string on 4.4+ server")
                 .test("crud", "findOneAndDelete-hint-unacknowledged", "Unacknowledged findOneAndDelete with hint document on 4.4+ server");
 
+        def.skipNoncompliant("driver-kotlin-coroutine has bug in emulating collection's findOne() method")
+                .when(() -> def.isReactive() && UnifiedTest.Language.KOTLIN.equals(def.getLanguage()))
+                .file("crud", "findOne");
+
         // gridfs
 
         def.skipDeprecated("contentType is deprecated in GridFS spec, and 4.x Java driver no longer supports it")
@@ -256,24 +260,28 @@ public static void applyCustomizations(final TestDef def) {
 
     private UnifiedTestModifications() {}
 
-    public static TestDef testDef(final String dir, final String file, final String test, final boolean reactive) {
-        return new TestDef(dir, file, test, reactive);
+    public static TestDef testDef(final String dir, final String file, final String test, final boolean reactive,
+            final UnifiedTest.Language language) {
+        return new TestDef(dir, file, test, reactive, language);
     }
 
     public static final class TestDef {
+
         private final String dir;
         private final String file;
         private final String test;
         private final boolean reactive;
+        private final UnifiedTest.Language language;
 
         private final List<Modifier> modifiers = new ArrayList<>();
         private Function<Throwable, Boolean> matchesThrowable;
 
-        private TestDef(final String dir, final String file, final String test, final boolean reactive) {
+        private TestDef(final String dir, final String file, final String test, final boolean reactive, final UnifiedTest.Language language) {
             this.dir = assertNotNull(dir);
             this.file = assertNotNull(file);
             this.test = assertNotNull(test);
             this.reactive = reactive;
+            this.language = language;
         }
 
         /**
@@ -354,6 +362,10 @@ public boolean isReactive() {
             return reactive;
         }
 
+        public UnifiedTest.Language getLanguage() {
+            return language;
+        }
+
         public boolean wasAssignedModifier(final Modifier modifier) {
             return this.modifiers.contains(modifier);
         }