feat: add UITextView validation support

Author: ns-vasilev

Sources/ValidatorUI/Classes/UIKit/Extensions/UITextView+Validation.swift

@@ -0,0 +1,48 @@
+//
+// Validator
+// Copyright © 2025 Space Code. All rights reserved.
+//
+
+#if os(iOS)
+    import UIKit
+
+    extension UITextView: IUIValidatable {
+        /// The value of the text view to validate.
+        /// Returns an empty string if `text` is nil.
+        public var inputValue: String { text ?? "" }
+
+        /// The type of input for validation.
+        public typealias Input = String
+
+        /// Enables or disables automatic validation when the text changes.
+        ///
+        /// - Parameter isEnabled: If true, adds an observer for text changes.
+        ///                        If false, removes the observer.
+        public func validateOnInputChange(isEnabled: Bool) {
+            if isEnabled {
+                NotificationCenter.default.addObserver(
+                    self,
+                    selector: #selector(textViewDidChangeNotification(_:)),
+                    name: UITextView.textDidChangeNotification,
+                    object: self
+                )
+            } else {
+                NotificationCenter.default.removeObserver(
+                    self,
+                    name: UITextView.textDidChangeNotification,
+                    object: self
+                )
+            }
+        }
+
+        // MARK: Private
+
+        /// Called automatically when the text view changes via NotificationCenter.
+        @objc
+        private func textViewDidChangeNotification(_ notification: Notification) {
+            guard let textView = notification.object as? UITextView, textView === self else { return }
+
+            validate(rules: validationRules)
+        }
+    }
+#endif

Tests/ValidatorUITests/UnitTests/UITextViewTests.swift

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+//
+// Validator
+// Copyright © 2025 Space Code. All rights reserved.
+//
+
+import ValidatorCore
+import ValidatorUI
+import XCTest
+
+#if canImport(UIKit)
+    import UIKit
+#endif
+
+#if os(iOS)
+    final class UITextViewTests: XCTestCase {
+        // MARK: Tests
+
+        @MainActor
+        func test_thatTextViewValidationReturnsValid_whenInputValueIsValid() {
+            // given
+            let textView = UITextView()
+
+            textView.validateOnInputChange(isEnabled: true)
+            textView.add(rule: LengthValidationRule(max: .max, error: String.error))
+
+            // when
+            textView.text = String(String.text.prefix(.max))
+
+            var result: ValidationResult?
+
+            textView.validationHandler = { result = $0 }
+            textView.validate(rules: textView.validationRules)
+
+            // when
+            if case .valid = result {}
+            else { XCTFail("The result must be equal to the valid value") }
+        }
+
+        @MainActor
+        func test_thatTextViewValidationReturnsInvalid_whenInputValueIsInvalid() {
+            // given
+            let textView = UITextView()
+
+            textView.validateOnInputChange(isEnabled: true)
+            textView.add(rule: LengthValidationRule(max: .max, error: String.error))
+
+            // when
+            textView.text = .text
+
+            var result: ValidationResult?
+
+            textView.validationHandler = { result = $0 }
+            textView.validate(rules: textView.validationRules)
+
+            // when
+            if case let .invalid(errors) = result {
+                XCTAssertEqual(errors.count, 1)
+                XCTAssertEqual(errors.first?.message, .error)
+            } else { XCTFail("The result must be equal to the invalid value") }
+        }
+    }
+#endif
+
+private extension String {
+    static let text: String = "lorem ipsum lorem ipsum lorem ipsum"
+    static let error: String = "error"
+}
+
+private extension Int {
+    static let min = 0
+    static let max = 10
+}