Implemented the TemplateService service in the library target.

Library/Sources/Public/Services/FileService.swift

@@ -1,6 +1,6 @@
 import Foundation
 
-public struct FileService: FileServicing {
+public struct FileService {
     
     // MARK: Properties
     
@@ -12,6 +12,12 @@ public struct FileService: FileServicing {
         self.fileManager = fileManager
     }
     
+}
+
+// MARK: - FileServicing
+
+extension FileService: FileServicing {
+
     // MARK: Computed
     
     public var currentFolder: URL {

Library/Sources/Public/Services/TemplateService.swift

@@ -0,0 +1,50 @@
+import Foundation
+import Mustache
+
+public struct TemplateService {
+    
+    // MARK: Properties
+    
+    private let mustacheRenderer: MustacheLibrary
+    
+    // MARK: Initialisers
+    
+    public init(
+        bundle: Bundleable? = nil,
+        templateFolder: String
+    ) async throws (TemplateServiceError) {
+        guard let pathResources = (bundle ?? Bundle.module).resourcePath else {
+            throw .resourcePathNotFound
+        }
+        
+        let pathTemplates = pathResources + "/" + templateFolder
+        
+        do {
+            self.mustacheRenderer = try await MustacheLibrary(directory: pathTemplates)
+        } catch {
+            throw .serviceNotInitialized
+        }
+    }
+    
+}
+
+// MARK: - TemplateServicing
+
+extension TemplateService: TemplateServicing {
+
+    // MARK: Functions
+    
+    public func render(_ object: Any, on template: String) async throws (TemplateServiceError) -> String {
+        guard mustacheRenderer.getTemplate(named: template) != nil else {
+            throw .templateNotFound
+        }
+        
+        guard let content = mustacheRenderer.render(object, withTemplate: template) else {
+            throw .contentNotRendered
+        }
+        
+        return content
+    }
+    
+}
+

Test/Sources/Cases/Public/Services/TemplateServiceTests.swift

@@ -0,0 +1,47 @@
+import ColibriLibrary
+import Foundation
+import Testing
+
+struct TemplateServiceTests {
+    
+    // MARK: Properties
+    
+    private let spy = TemplateServiceSpy()
+    
+    // MARK: Functions tests
+
+    @Test(arguments: [String.content])
+    func render(_ content: String) async throws {
+        // GIVEN
+        let service = TemplateServiceMock(action: .render(content), spy: spy)
+        
+        // WHEN
+        let result = try await service.render([:], on: .template)
+        
+        // THEN
+        #expect(result == content)
+
+        #expect(spy.actions.isEmpty == false)
+    }
+    
+    @Test(arguments: [TemplateServiceError.serviceNotInitialized, .resourcePathNotFound, .templateNotFound, .contentNotRendered])
+    func render(throws error: TemplateServiceError) async throws {
+        let service = TemplateServiceMock(action: .error(error), spy: spy)
+        
+        // WHEN
+        // THEN
+        await #expect(throws: error) {
+            try await service.render([:], on: .template)
+        }
+        
+        #expect(spy.actions.isEmpty == true)
+    }
+
+}
+
+// MARK: - String+Constants
+
+private extension String {
+    static let content = ""
+    static let template = ""
+}

Test/Sources/Helpers/Mocks/TemplateServiceMock.swift

@@ -0,0 +1,75 @@
+import ColibriLibrary
+import Foundation
+
+final class TemplateServiceMock {
+    
+    // MARK: Properties
+    
+    private var actions: [Action] = []
+    
+    private weak var spy: TemplateServiceSpy?
+    
+    // MARK: Initialisers
+    
+    init(
+        action: Action,
+        spy: TemplateServiceSpy? = nil
+    ) {
+        self.actions.append(action)
+        self.spy = spy
+    }
+    
+}
+
+// MARK: - TemplateServicing
+
+extension TemplateServiceMock: TemplateServicing {
+    
+    // MARK: Functions
+    
+    @discardableResult
+    func render(_ object: Any, on template: String) async throws(TemplateServiceError) -> String {
+        guard let nextAction else { return .empty }
+        
+        switch nextAction {
+        case .error(let error):
+            throw error
+        case .render(let content):
+            try await spy?.render(object, on: template)
+            return content
+        }
+    }
+    
+}
+
+// MARK: - Helpers
+
+private extension TemplateServiceMock {
+    
+    // MARK: Computed
+    
+    var nextAction: Action? {
+        guard !actions.isEmpty else {
+            return nil
+        }
+        
+        return actions.removeFirst()
+    }
+    
+}
+
+
+// MARK: - Actions
+
+extension TemplateServiceMock {
+    enum Action {
+        case error(TemplateServiceError)
+        case render(String)
+    }
+}
+
+// MARK: - String+Constants
+
+private extension String {
+    static let empty = ""
+}

Test/Sources/Helpers/Spies/FileServiceSpy.swift

@@ -1,7 +1,6 @@
+import ColibriLibrary
 import Foundation
 
-@testable import ColibriLibrary
-
 final class FileServiceSpy {
     
     // MARK: Properties

Test/Sources/Helpers/Spies/TemplateServiceSpy.swift

@@ -0,0 +1,38 @@
+import ColibriLibrary
+
+final class TemplateServiceSpy {
+    
+    // MARK: Properties
+    
+    private(set) var actions: [Action] = []
+    
+}
+
+// MARK: - TemplateServicing
+
+extension TemplateServiceSpy: TemplateServicing {
+    
+    // MARK: Functions
+    
+    @discardableResult
+    func render(_ object: Any, on template: String) async throws(TemplateServiceError) -> String {
+        actions.append(.rendered(object, template))
+        
+        return .content
+    }
+    
+}
+
+// MARK: - Actions
+
+extension TemplateServiceSpy {
+    enum Action {
+        case rendered(_ object: Any, _ template: String)
+    }
+}
+
+// MARK: - String+Constants
+
+private extension String {
+    static let content = ""
+}