Implemented the "empty" constant and the "isNotEmpty()" function in the String+Empty extension.

Sources/Core/Extensions/String+Empty.swift

@@ -0,0 +1,24 @@
+//
+//  String+Empty.swift
+//  Core
+//
+//  Created by Javier Cicchelli on 15/04/2023.
+//  Copyright © 2023 Röck+Cöde. All rights reserved.
+//
+
+public extension String {
+    
+    // MARK: Properties
+    
+    /// Represents an empty string.
+    static let empty = ""
+    
+    // MARK: Functions
+    
+    /// Checks whether a string is not empty.
+    /// - Returns: A boolean value that represents whether the string is not empty.
+    func isNotEmpty() -> Bool {
+        isEmpty == false
+    }
+    
+}

Sources/Core/SwiftLibs.swift

@@ -1,6 +0,0 @@
-public struct SwiftLibs {
-    public private(set) var text = "Hello, World!"
-
-    public init() {
-    }
-}

Tests/Core/Extensions/String+EmptyTests.swift

@@ -0,0 +1,56 @@
+//
+//  String+EmptyTests.swift
+//  Core
+//
+//  Created by Javier Cicchelli on 15/04/2023.
+//  Copyright © 2022 Röck+Cöde. All rights reserved.
+//
+
+import XCTest
+
+@testable import Core
+
+final class String_EmptyTests: XCTestCase {
+
+    // MARK: Tests
+
+    func test_empty() {
+        // GIVEN
+        let string = String.empty
+        
+        // WHEN
+        // THEN
+        XCTAssertEqual(string, "")
+    }
+    
+    func test_isNotEmpty_withEmptyString() {
+        // GIVEN
+        let string = String.empty
+        
+        // WHEN
+        let result = string.isNotEmpty()
+        
+        // THEN
+        XCTAssertFalse(result)
+    }
+    
+    func test_isNotEmpty_withFilledString() {
+        // GIVEN
+        let string = String.Test.string
+        
+        // WHEN
+        let result = string.isNotEmpty()
+        
+        // THEN
+        XCTAssertTrue(result)
+    }
+
+}
+
+// MARK: - String+Constants
+
+private extension String {
+    enum Test {
+        static let string = "Some test string..."
+    }
+}

Tests/Core/SwiftLibsTests.swift

@@ -1,11 +0,0 @@
-import XCTest
-@testable import SwiftLibs
-
-final class SwiftLibsTests: XCTestCase {
-    func testExample() throws {
-        // This is an example of a functional test case.
-        // Use XCTAssert and related functions to verify your tests produce the correct
-        // results.
-        XCTAssertEqual(SwiftLibs().text, "Hello, World!")
-    }
-}