Update merge test case for PropertyList

Author: Kyle-Ye

Sources/OpenSwiftUICore/Data/PropertyList.swift

@@ -202,7 +202,15 @@ package struct PropertyList: CustomStringConvertible {
     }
 
     package mutating func merge(_ plist: PropertyList) {
-         preconditionFailure("TODO")
+//        preconditionFailure("TODO")
+
+        var copyCount = 0
+        guard copyCount != 0 else {
+            return
+        }
+        withUnsafeTuple(of: TupleType(Element.self), count: copyCount) { tuple in
+            // TODO
+        }
     }
 
     package func merging(_ other: PropertyList) -> PropertyList {

Tests/OpenSwiftUICoreTests/Data/PropertyListTests.swift

@@ -104,7 +104,7 @@ struct PropertyListTests {
     }
 
     @Test
-    func description() throws {
+    func description() {
         var plist = PropertyList()
         #expect(plist.description == "[]")
 
@@ -124,6 +124,24 @@ struct PropertyListTests {
         plist[IntKey.self] = value
         #expect(plist.description == "[\(IntKey.self) = \(value), \(BoolKey.self) = \(bool), \(BoolKey.self) = \(BoolKey.defaultValue)]")
     }
+
+    @Test
+    func merging() {
+        var plist1 = PropertyList()
+        plist1[IntKey.self] = 42
+        var plist2 = PropertyList()
+        plist2[StringKey.self] = "Hello"
+
+        let plist3 = plist1.merging(plist2)
+        let plist4 = plist2.merging(plist1)
+
+        #expect(plist3.description == #"""
+        [StringKey = Hello, IntKey = 42]
+        """#)
+        #expect(plist4.description == #"""
+        [IntKey = 42, StringKey = Hello]
+        """#)
+    }
 }
 
 struct PropertyListTrackerTests {

Tests/OpenSwiftUISymbolDualTests/Data/PropertyListTests.swift

@@ -163,7 +163,7 @@ struct PropertyListTests {
     }
 
     @Test
-    func description() throws {
+    func description() {
         var plist = PropertyList(swiftUI: ())
         #expect(plist.swiftUI_description == "[]")
 
@@ -183,6 +183,24 @@ struct PropertyListTests {
         plist[swiftUI: IntKey.self] = value
         #expect(plist.swiftUI_description == "[\(IntKey.self) = \(value), \(BoolKey.self) = \(bool), \(BoolKey.self) = \(BoolKey.defaultValue)]")
     }
+
+    @Test
+    func merging() {
+        var plist1 = PropertyList(swiftUI: ())
+        plist1[swiftUI: IntKey.self] = 42
+        var plist2 = PropertyList(swiftUI: ())
+        plist2[swiftUI: StringKey.self] = "Hello"
+
+        let plist3 = plist1.swiftUI_merging(plist2)
+        let plist4 = plist2.swiftUI_merging(plist1)
+
+        #expect(plist3.swiftUI_description == #"""
+        [StringKey = Hello, IntKey = 42]
+        """#)
+        #expect(plist4.swiftUI_description == #"""
+        [IntKey = 42, StringKey = Hello]
+        """#)
+    }
 }
 
 extension PropertyList.Tracker {