Implement DynamicNodeDecoding with tests

Sources/XMLCoder/Decoder/XMLDecoder.swift

@@ -256,7 +256,10 @@ open class XMLDecoder {
         ) -> ((CodingKey) -> NodeDecoding) {
             switch self {
             case .deferredToDecoder:
-                return { _ in .elementOrAttribute }
+                guard let dynamicType = codableType as? DynamicNodeDecoding.Type else {
+                    return { _ in .elementOrAttribute }
+                }
+                return dynamicType.nodeDecoding(for:)
             case let .custom(closure):
                 return closure(codableType, decoder)
             }

Tests/XMLCoderTests/DynamicNodeDecodingTest.swift

@@ -0,0 +1,214 @@
+//
+//  DynamicNodeEncodingTest.swift
+//  XMLCoderTests
+//
+//  Created by Joseph Mattiello on 1/23/19.
+//
+
+import Foundation
+import XCTest
+@testable import XMLCoder
+
+private let overlappingKeys = """
+<?xml version="1.0" encoding="UTF-8"?>
+<test key="123">
+    <key>
+        StringValue
+    </key>
+</test>
+""".data(using: .utf8)!
+
+private let libraryXMLYN = """
+<?xml version="1.0" encoding="UTF-8"?>
+<library count="2">
+    <book id="123">
+        <id>123</id>
+        <title>Cat in the Hat</title>
+        <category main="Y"><value>Kids</value></category>
+        <category main="N"><value>Wildlife</value></category>
+    </book>
+    <book id="456">
+        <id>456</id>
+        <title>1984</title>
+        <category main="Y"><value>Classics</value></category>
+        <category main="N"><value>News</value></category>
+    </book>
+</library>
+""".data(using: .utf8)!
+
+private let libraryXMLYNStrategy = """
+<?xml version="1.0" encoding="UTF-8"?>
+<library>
+    <count>2</count>
+    <book title="Cat in the Hat">
+        <id>123</id>
+        <category>
+            <main>true</main>
+            <value>Kids</value>
+        </category>
+        <category>
+            <main>false</main>
+            <value>Wildlife</value>
+        </category>
+    </book>
+    <book title="1984">
+        <id>456</id>
+        <category>
+            <main>true</main>
+            <value>Classics</value>
+        </category>
+        <category>
+            <main>false</main>
+            <value>News</value>
+        </category>
+    </book>
+</library>
+""".data(using: .utf8)!
+
+private struct TestStruct: Codable, Equatable, DynamicNodeDecoding {
+    let attribute: Int
+    let element: String
+
+    private enum CodingKeys: CodingKey {
+        case attribute
+        case element
+
+        public var stringValue: String {
+            return "key"
+        }
+    }
+
+    static func nodeDecoding(for key: CodingKey) -> XMLDecoder.NodeDecoding {
+        switch key {
+        case CodingKeys.attribute:
+            return .attribute
+        default:
+            return .element
+        }
+    }
+}
+
+private struct Library: Codable, Equatable, DynamicNodeDecoding {
+    let count: Int
+    let books: [Book]
+
+    enum CodingKeys: String, CodingKey {
+        case count
+        case books = "book"
+    }
+
+    static func nodeDecoding(for key: CodingKey) -> XMLDecoder.NodeDecoding {
+        switch key {
+        case CodingKeys.count:
+            return .attribute
+        default:
+            return .element
+        }
+    }
+}
+
+private struct Book: Codable, Equatable, DynamicNodeEncoding {
+    let id: UInt
+    let title: String
+    let categories: [Category]
+
+    enum CodingKeys: String, CodingKey {
+        case id
+        case title
+        case categories = "category"
+    }
+
+    static func nodeEncoding(for key: CodingKey) -> XMLEncoder.NodeEncoding {
+        switch key {
+        case Book.CodingKeys.id: return .both
+        default: return .element
+        }
+    }
+}
+
+private struct Category: Codable, Equatable, DynamicNodeEncoding {
+    let main: Bool
+    let value: String
+
+    private enum CodingKeys: String, CodingKey {
+        case main
+        case value
+    }
+
+    static func nodeEncoding(for key: CodingKey) -> XMLEncoder.NodeEncoding {
+        switch key {
+        case Category.CodingKeys.main:
+            return .attribute
+        default:
+            return .element
+        }
+    }
+}
+
+final class DynamicNodeDecodingTest: XCTestCase {
+    func testDecode() throws {
+        let decoder = XMLDecoder()
+        decoder.errorContextLength = 10
+
+        let library = try decoder.decode(Library.self, from: libraryXMLYN)
+        XCTAssertEqual(library.books.count, 2)
+        XCTAssertEqual(library.count, 2)
+
+        let book1 = library.books[0]
+        XCTAssertEqual(book1.id, 123)
+        XCTAssertEqual(book1.title, "Cat in the Hat")
+
+        let book1Categories = book1.categories
+        XCTAssertEqual(book1Categories.count, 2)
+        XCTAssertEqual(book1Categories[0].value, "Kids")
+        XCTAssertTrue(book1Categories[0].main)
+        XCTAssertEqual(book1Categories[1].value, "Wildlife")
+        XCTAssertFalse(book1Categories[1].main)
+
+        let book2 = library.books[1]
+        XCTAssertEqual(book2.id, 456)
+        XCTAssertEqual(book2.title, "1984")
+
+        let book2Categories = book2.categories
+        XCTAssertEqual(book2Categories.count, 2)
+        XCTAssertEqual(book2Categories[0].value, "Classics")
+        XCTAssertTrue(book2Categories[0].main)
+        XCTAssertEqual(book2Categories[1].value, "News")
+        XCTAssertFalse(book2Categories[1].main)
+    }
+
+    func testStrategyPriority() throws {
+        let decoder = XMLDecoder()
+        decoder.errorContextLength = 10
+
+        decoder.nodeDecodingStrategy = .custom { type, _ in
+            { key in
+                guard
+                    type == Book.self &&
+                    key.stringValue == Book.CodingKeys.title.stringValue
+                else {
+                    return .element
+                }
+
+                return .attribute
+            }
+        }
+
+        let library = try decoder.decode(Library.self, from: libraryXMLYNStrategy)
+        XCTAssertEqual(library.count, 2)
+    }
+
+    func testOverlappingKeys() throws {
+        let decoder = XMLDecoder()
+        decoder.errorContextLength = 10
+
+        let test = try decoder.decode(TestStruct.self, from: overlappingKeys)
+        XCTAssertEqual(test, TestStruct(attribute: 123, element: "StringValue"))
+    }
+
+    static var allTests = [
+        ("testDecode", testDecode),
+        ("testStrategyPriority", testStrategyPriority),
+        ("testOverlappingKeys", testOverlappingKeys),
+    ]
+}

Tests/XMLCoderTests/SingleChildTests.swift

@@ -12,7 +12,7 @@ struct ProudParent: Codable, Equatable {
     var myChildAge: [Int]
 }
 
-final class Test: XCTestCase {
+final class SingleChildTest: XCTestCase {
     func testEncoder() throws {
         let encoder = XMLEncoder()
 

XMLCoder.xcodeproj/project.pbxproj

@@ -87,6 +87,7 @@
 		D14D8A8621F1D6B300B0D31A /* SingleChildTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = D14D8A8521F1D6B300B0D31A /* SingleChildTests.swift */; };
 		D158F12F2229892C0032B449 /* DynamicNodeDecoding.swift in Sources */ = {isa = PBXBuildFile; fileRef = D158F12E2229892C0032B449 /* DynamicNodeDecoding.swift */; };
 		D162674321F9B2AF0056D1D8 /* OptionalTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = D162674121F9B2850056D1D8 /* OptionalTests.swift */; };
+		D1761D1F2247F04500F53CEF /* DynamicNodeDecodingTest.swift in Sources */ = {isa = PBXBuildFile; fileRef = D1761D1E2247F04500F53CEF /* DynamicNodeDecodingTest.swift */; };
 		D1CB1EF521EA9599009CAF02 /* RJITest.swift in Sources */ = {isa = PBXBuildFile; fileRef = OBJ_37 /* RJITest.swift */; };
 		D1CFC8242226B13F00B03222 /* NamespaceTest.swift in Sources */ = {isa = PBXBuildFile; fileRef = D1CFC8222226AFB400B03222 /* NamespaceTest.swift */; };
 		D1E0C85321D8E65E0042A261 /* ErrorContextTest.swift in Sources */ = {isa = PBXBuildFile; fileRef = D1E0C85121D8E6540042A261 /* ErrorContextTest.swift */; };
@@ -203,6 +204,7 @@
 		D14D8A8521F1D6B300B0D31A /* SingleChildTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SingleChildTests.swift; sourceTree = "<group>"; };
 		D158F12E2229892C0032B449 /* DynamicNodeDecoding.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DynamicNodeDecoding.swift; sourceTree = "<group>"; };
 		D162674121F9B2850056D1D8 /* OptionalTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = OptionalTests.swift; sourceTree = "<group>"; };
+		D1761D1E2247F04500F53CEF /* DynamicNodeDecodingTest.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DynamicNodeDecodingTest.swift; sourceTree = "<group>"; };
 		D1CFC8222226AFB400B03222 /* NamespaceTest.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NamespaceTest.swift; sourceTree = "<group>"; };
 		D1E0C85121D8E6540042A261 /* ErrorContextTest.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = ErrorContextTest.swift; sourceTree = "<group>"; };
 		D1E0C85421D91EBF0042A261 /* Metatypes.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Metatypes.swift; sourceTree = "<group>"; };
@@ -389,6 +391,7 @@
 				D1FC040421C7EF8200065B43 /* RJISample.swift */,
 				B3B6902D220A71DF0084D407 /* AttributedIntrinsicTest.swift */,
 				B3BE1D602202C1F600259831 /* DynamicNodeEncodingTest.swift */,
+				D1761D1E2247F04500F53CEF /* DynamicNodeDecodingTest.swift */,
 				A61DCCD621DF8DB300C0A19D /* ClassTests.swift */,
 				D14D8A8521F1D6B300B0D31A /* SingleChildTests.swift */,
 				D1CFC8222226AFB400B03222 /* NamespaceTest.swift */,
@@ -638,6 +641,7 @@
 				D1CFC8242226B13F00B03222 /* NamespaceTest.swift in Sources */,
 				BF9457D021CBB516005ACFDE /* UIntBoxTests.swift in Sources */,
 				OBJ_80 /* BooksTest.swift in Sources */,
+				D1761D1F2247F04500F53CEF /* DynamicNodeDecodingTest.swift in Sources */,
 				OBJ_81 /* BreakfastTest.swift in Sources */,
 				OBJ_82 /* CDCatalog.swift in Sources */,
 				BF63EF0021CCDED2001D38C5 /* XMLStackParserTests.swift in Sources */,