SWIFT-973 Fix crash when encoding top level arrays to BSON (#35)

Author: nspektor

Sources/BSON/BSONEncoder.swift

@@ -217,6 +217,9 @@ public class BSONEncoder {
             if let mutableDict = boxedValue as? MutableDictionary {
                 return .document(try mutableDict.toDocument())
             }
+            if let mutableArray = boxedValue as? MutableArray {
+                return .array(try mutableArray.toBSONArray())
+            }
             return boxedValue.bson
         } catch let error as BSONErrorProtocol {
             throw EncodingError.invalidValue(

Tests/BSONTests/CodecTests.swift

@@ -830,4 +830,11 @@ final class CodecTests: BSONTestCase {
         expect(try encoder.encode(IncorrectTopLevelEncode(.null))).to(throwError(CodecTests.invalidValueErr))
         expect(try encoder.encode(CorrectTopLevelEncode(.null))).to(equal(["x": [:]]))
     }
+
+    func testTopLevelArray() {
+        let encoder = BSONEncoder()
+        let decoder = BSONDecoder()
+        expect(try encoder.encodeFragment([1, 2, 3])).to(equal([1, 2, 3]))
+        expect(try decoder.decode([Int].self, fromBSON: [1, 2, 3])).to(equal([1, 2, 3]))
+    }
 }