Swift tests and api update

Objective-C/Internal/CBLCollection+Swift.h

@@ -28,6 +28,8 @@ NS_ASSUME_NONNULL_BEGIN
 
 @property (nonatomic, readonly) BOOL isValid;
 
+- (nullable NSArray*) indexesInfo: (NSError**)error;
+
 @end
 
 NS_ASSUME_NONNULL_END

Swift/Collection.swift

@@ -352,6 +352,10 @@ public final class Collection : CollectionChangeObservable, Indexable, Equatable
 
     // MARK: Internal
 
+    func indexesInfo() throws -> [[String: Any]]? {
+        return try impl.indexesInfo() as? [[String: Any]]
+    }
+
     init(_ impl: CBLCollection, db: Database) {
         self.impl = impl
         self.database = db

Swift/IndexConfiguration.swift

@@ -88,7 +88,12 @@ public struct ArrayIndexConfiguration: IndexConfiguration, IndexConfigConvertabl
     ///     represents an expression defining the values within the array to be indexed.
     ///     If the array specified by the path contains scalar values, this parameter can be null.
     /// - Returns The ArrayIndexConfiguration object.
-    public init(path: String, _ expressions: [String]?) {
+    public init(path: String, _ expressions: [String]? = nil) {
+        if let expressions = expressions, expressions.isEmpty {
+            NSException(name: .invalidArgumentException,
+                        reason: "Empty expressions is not allowed, use nil instead",
+                        userInfo: nil).raise()
+        }
         self.path = path
         self.expressions = expressions
     }

Swift/Tests/UnnestArrayTest.swift

@@ -0,0 +1,81 @@
+//
+//  UnnestArrayTest.swift
+//  CouchbaseLite
+//
+//  Copyright (c) 2024 Couchbase, Inc. All rights reserved.
+//
+//  Licensed under the Couchbase License Agreement (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//  https://info.couchbase.com/rs/302-GJY-034/images/2017-10-30_License_Agreement.pdf
+//
+//  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.
+//
+
+import XCTest
+@testable import CouchbaseLiteSwift
+
+/// Test Spec v1.0.1:
+/// https://github.com/couchbaselabs/couchbase-lite-api/blob/master/spec/tests/T0004-Unnest-Array-Index.md
+
+class UnnestArrayTest: CBLTestCase {
+    /// 1. TestArrayIndexConfigInvalidExpressions
+    /// Description
+    ///     Test that creating an ArrayIndexConfiguration with invalid expressions which are an empty expressions or contain null.
+    /// Steps
+    ///     1. Create a ArrayIndexConfiguration object.
+    ///         - path: "contacts"
+    ///         - expressions: []
+    ///     2. Check that an invalid arument exception is thrown.
+    func testArrayIndexConfigInvalidExpressions() throws {
+        expectException(exception: .invalidArgumentException) {
+            _ = ArrayIndexConfiguration(path: "contacts", [])
+        }
+    }
+
+    /// 2. TestCreateArrayIndexWithPath
+    /// Description
+    ///     Test that creating an ArrayIndexConfiguration with invalid expressions which are an empty expressions or contain null.
+    /// Steps
+    ///     1. Load profiles.json into the collection named "_default.profiles".
+    ///     2. Create a ArrayIndexConfiguration object.
+    ///         - path: "contacts"
+    ///         - expressions: null
+    ///     3. Create an array index named "contacts" in the profiles collection.
+    ///     4. Get index names from the profiles collection and check that the index named "contacts" exists.
+    ///     5. Get info of the index named "contacts" using an internal API and check that the index has path and expressions as configured.
+    func testCreateArrayIndexWithPath() throws {
+        let profiles = try db.createCollection(name: "profiles")
+        try loadJSONResource("profiles_100", collection: profiles)
+        let config = ArrayIndexConfiguration(path: "contacts")
+        try profiles.createIndex(withName: "contacts", config: config)
+        let indexes = try profiles.indexesInfo()
+        XCTAssertEqual(indexes!.count, 1)
+        XCTAssertEqual(indexes![0]["expr"] as! String, "")
+    }
+
+    /// 3. TestCreateArrayIndexWithPathAndExpressions
+    /// Description
+    ///     Test that creating an array index with path and expressions works as expected.
+    /// Steps
+    ///     1. Load profiles.json into the collection named "_default.profiles".
+    ///     2. Create a ArrayIndexConfiguration object.
+    ///         - path: "contacts"
+    ///         - expressions: ["address.city", "address.state"]
+    ///     3. Create an array index named "contacts" in the profiles collection.
+    ///     4. Get index names from the profiles collection and check that the index named "contacts" exists.
+    ///     5. Get info of the index named "contacts" using an internal API and check that the index has path and expressions as configured.
+    func testCreateArrayIndexWithPathAndExpressions() throws {
+        let profiles = try db.createCollection(name: "profiles")
+        try loadJSONResource("profiles_100", collection: profiles)
+        let config = ArrayIndexConfiguration(path: "contacts", ["address.city", "address.state"])
+        try profiles.createIndex(withName: "contacts", config: config)
+        let indexes = try profiles.indexesInfo()
+        XCTAssertEqual(indexes!.count, 1)
+        XCTAssertEqual(indexes![0]["expr"] as! String, "address.city,address.state")
+    }
+}