Add BindingTests (#33)

Tests/OpenSwiftUITests/DataAndStorage/ModelData/Binding/BindingTests.swift

@@ -0,0 +1,263 @@
+//
+//  BindingTests.swift
+//
+//
+//  Created by Kyle on 2024/2/1.
+//
+
+@testable import OpenSwiftUI
+import Testing
+
+struct BindingTests {
+    @Test("Test Binding.init(get:set:)")
+    func initWithGetterSetter() {
+        var storage = 0
+        let binding = Binding {
+            storage
+        } set: { newValue in
+            storage = newValue
+        }
+        #expect(binding.wrappedValue == 0)
+
+        let newValue = 10
+        binding.wrappedValue = newValue
+        #expect(binding.wrappedValue == newValue)
+        #expect(storage == newValue)
+    }
+
+    @Test("Test Binding.init(get:set:) with transaction")
+    func initWithGetterSetterWithTransaction() {
+        var storage = 0
+        var transaction = Transaction(animation: .default)
+
+        let binding = Binding {
+            storage
+        } set: { newValue, newTransaction in
+            storage = newValue
+            transaction = newTransaction
+        }
+
+        #expect(binding.wrappedValue == 0)
+        #expect(storage == 0)
+        #expect(transaction.animation == .default)
+
+        binding.wrappedValue = 10
+        #expect(binding.wrappedValue == 10)
+        #expect(storage == 10)
+        #expect(transaction.animation == nil)
+    }
+
+    @Test("Test Binding.constant")
+    func initWithConstantValue() {
+        let binding = Binding.constant(0)
+        #expect(binding.location.wasRead == true)
+        binding.location.wasRead = false
+        #expect(binding.location.wasRead == true)
+        binding.wrappedValue = 5
+        #expect(binding.wrappedValue == 0)
+    }
+
+    @Test("Test Binding's projectedValue")
+    func bindingProjectingValue() {
+        struct T {
+            var name: String
+        }
+
+        let binding = Binding.constant(T(name: "test"))
+        #expect(binding.location === binding.projectedValue.location)
+
+        let newBinding = Binding(projectedValue: binding)
+        #expect(binding.location === newBinding.location)
+
+        let nameBinding = binding.name
+        #expect(nameBinding.wrappedValue == "test")
+    }
+
+    @Test
+    func initBindingToOptionalBinding() {
+        var storage = 0
+        let baseBinding = Binding {
+            storage
+        } set: { newValue in
+            storage = newValue
+        }
+        #expect(baseBinding.wrappedValue == 0)
+
+        let optionalBinding: Binding<Int?> = Binding(baseBinding)
+        #expect(optionalBinding.wrappedValue == 0)
+
+        optionalBinding.wrappedValue = 10
+        #expect(optionalBinding.wrappedValue == 0)
+        storage = 20
+        #expect(optionalBinding.wrappedValue == 20)
+        optionalBinding.wrappedValue = nil
+        #expect(optionalBinding.wrappedValue == 20)
+    }
+
+    @Test("Test Binding.init?(_:)")
+    func initWithBindingOptionalValue() {
+        struct FunctionalLocationWithWasRead<Value>: Location {
+            var getValue: () -> Value
+            var setValue: (Value, Transaction) -> Void
+            var wasRead = false
+            func get() -> Value { getValue() }
+            func set(_ value: Value, transaction: Transaction) { setValue(value, transaction) }
+        }
+        class Wrapper {
+            var storage: Int?
+        }
+
+        let wrapper = Wrapper()
+        let location = LocationBox(location: FunctionalLocationWithWasRead(getValue: {
+            wrapper.storage
+        }, setValue: { newValue, _ in
+            wrapper.storage = newValue
+        }))
+
+        _ = {
+            wrapper.storage = nil
+            let baseBinding = Binding(value: location.get(), location: location)
+            #expect(baseBinding.location.wasRead == false)
+            #expect(GraphHost.isUpdating == false)
+
+            // _value: nil
+            // location.get(): nil
+            // GraphHost.isUpdating: false
+            // - location.get()
+            let binding1 = Binding(baseBinding)
+            #expect(binding1 == nil)
+
+            wrapper.storage = 0
+            // _value: nil
+            // location.get(): 0
+            // GraphHost.isUpdating: false
+            // - location.get()
+
+            // MARK: Expected a forceUnwrap failure.
+
+            // swift-testing is tracking it via https://github.com/apple/swift-testing/issues/157
+            // #expectCrash(Binding(baseBinding))
+
+            GraphHost.isUpdating = true
+            #expect(GraphHost.isUpdating == true)
+
+            wrapper.storage = nil
+            // _value: nil
+            // location.get(): nil
+            // GraphHost.isUpdating: true
+            // - wasRead & _value
+            let binding3 = Binding(baseBinding)
+            #expect(baseBinding.location.wasRead == true)
+            #expect(binding3 == nil)
+            baseBinding.location.wasRead = false
+            #expect(baseBinding.location.wasRead == false)
+
+            wrapper.storage = 0
+            // _value: nil
+            // location.get(): 0
+            // GraphHost.isUpdating: true
+            // - wasRead & _value
+            let binding4 = Binding(baseBinding)
+            #expect(baseBinding.location.wasRead == true)
+            #expect(binding4 == nil)
+            baseBinding.location.wasRead = false
+            #expect(baseBinding.location.wasRead == false)
+
+            GraphHost.isUpdating = false
+            #expect(GraphHost.isUpdating == false)
+        }()
+
+        _ = {
+            wrapper.storage = 0
+            let baseBinding = Binding(value: location.get(), location: location)
+            #expect(baseBinding.location.wasRead == false)
+            #expect(GraphHost.isUpdating == false)
+
+            // _value: 0
+            // location.get(): 0
+            // GraphHost.isUpdating: false
+            // - location.get()
+            let binding1 = Binding(baseBinding)
+            #expect(binding1 != nil)
+
+            wrapper.storage = nil
+            // _value: 0
+            // location.get(): nil
+            // GraphHost.isUpdating: false
+            // - location.get()
+            let binding2 = Binding(baseBinding)
+            #expect(binding2 == nil)
+
+            GraphHost.isUpdating = true
+            #expect(GraphHost.isUpdating == true)
+
+            wrapper.storage = 0
+            // _value: 0
+            // location.get(): 0
+            // GraphHost.isUpdating: true
+            // - wasRead & _value
+            let binding3 = Binding(baseBinding)
+            #expect(baseBinding.location.wasRead == true)
+            #expect(binding3 != nil)
+            baseBinding.location.wasRead = false
+            #expect(baseBinding.location.wasRead == false)
+
+            wrapper.storage = nil
+            // _value: 0
+            // location.get(): nil
+            // GraphHost.isUpdating: true
+            // - wasRead & _value
+            let binding4 = Binding(baseBinding)
+            #expect(baseBinding.location.wasRead == true)
+            #expect(binding4 != nil)
+            baseBinding.location.wasRead = false
+            #expect(baseBinding.location.wasRead == false)
+
+            GraphHost.isUpdating = false
+            #expect(GraphHost.isUpdating == false)
+        }()
+    }
+
+    @Test
+    func initToAnyHashableBinding() {
+        var storage = 0
+        let baseBinding = Binding {
+            storage
+        } set: { newValue in
+            storage = newValue
+        }
+        #expect(baseBinding.wrappedValue == 0)
+
+        let anyHashableBinding: Binding<AnyHashable> = Binding(baseBinding)
+        #expect(anyHashableBinding.wrappedValue == AnyHashable(0))
+        anyHashableBinding.wrappedValue = 10
+        #expect(anyHashableBinding.wrappedValue == AnyHashable(0))
+        storage = 20
+        #expect(anyHashableBinding.wrappedValue == AnyHashable(20))
+        // #expectCrash(optionalBinding.wrappedValue = 0.0)
+    }
+
+    @Test
+    func identifiableValue() {
+        struct Storage: Identifiable {
+            var id: Int
+
+            var bindableID: Int {
+                get { id }
+                set { id = newValue }
+            }
+
+            var name: String
+        }
+        var storage = Storage(id: 0, name: "")
+        let binding = Binding {
+            storage
+        } set: { newValue in
+            storage = newValue
+        }
+        #expect(type(of: binding.id) == Int.self)
+        #expect(type(of: binding.bindableID) == Binding<Int>.self)
+        #expect(type(of: binding.name) == Binding<String>.self)
+        #expect(binding.id == storage.id)
+    }
+}