feat: More cli client tests and documentation.

Sources/CliClient/CliClient.swift

@@ -34,12 +34,23 @@ public struct CliClient {
 
   /// Represents the parameters needed to create an `MQTTClient`.
   ///
-  ///
   public struct ClientRequest: Sendable {
+
+    /// The environment variables used to create the client.
     public let environment: EnvVars
+
+    /// The event loop group for the client.
     public let eventLoopGroup: MultiThreadedEventLoopGroup
+
+    /// A logger to use with the client.
     public let logger: Logger?
 
+    /// Create a new client request.
+    ///
+    /// - Parameters:
+    ///   - environment: The environment variables to use.
+    ///   - eventLoopGroup: The event loop group to use on the client.
+    ///   - logger: An optional logger to use on the client.
     public init(
       environment: EnvVars,
       eventLoopGroup: MultiThreadedEventLoopGroup,
@@ -122,11 +133,10 @@ extension EnvVars {
     @Dependency(\.environment) var environment
 
     let defaultEnvVars = EnvVars()
-    let encoder = environment.jsonEncoder()
-    let decoder = environment.jsonDecoder()
+    let coders = environment.coders()
 
-    let defaultEnvDict = (try? encoder.encode(defaultEnvVars))
-      .flatMap { try? decoder.decode([String: String].self, from: $0) }
+    let defaultEnvDict = (try? coders.encode(defaultEnvVars))
+      .flatMap { try? coders.decode([String: String].self, from: $0) }
       ?? [:]
 
     let dotEnvDict = try await environment.dotEnvDict(path: dotEnvFile)
@@ -135,7 +145,7 @@ extension EnvVars {
       .merging(dotEnvDict, uniquingKeysWith: { $1 })
 
     var envVars = (try? JSONSerialization.data(withJSONObject: envVarsDict))
-      .flatMap { try? decoder.decode(EnvVars.self, from: $0) }
+      .flatMap { try? coders.decode(EnvVars.self, from: $0) }
       ?? defaultEnvVars
 
     if let version {
@@ -162,7 +172,7 @@ public extension MQTTClient {
       eventLoopGroupProvider: .shared(eventLoopGroup),
       logger: logger,
       configuration: .init(
-        version: .parseOrDefualt(string: envVars.version),
+        version: .parseOrDefault(string: envVars.version),
         disablePing: false,
         userName: envVars.userName,
         password: envVars.password
@@ -171,10 +181,11 @@ public extension MQTTClient {
   }
 }
 
-extension MQTTClient.Version {
+@_spi(Internal)
+public extension MQTTClient.Version {
   static let `default` = Self.v3_1_1
 
-  static func parseOrDefualt(string: String?) -> Self {
+  static func parseOrDefault(string: String?) -> Self {
     guard let string, let value = Self(string: string) else {
       return .default
     }

Sources/CliClient/EnvironmentDependency.swift

@@ -24,11 +24,7 @@ public extension DependencyValues {
 @DependencyClient
 public struct EnvironmentDependency: Sendable {
 
-  /// A json decoder to use to decode files and environment variables.
-  public var jsonDecoder: @Sendable () -> JSONDecoder = { JSONDecoder() }
-
-  /// A json encoder to use to encode files and environment variables.
-  public var jsonEncoder: @Sendable () -> JSONEncoder = { JSONEncoder() }
+  public var coders: @Sendable () -> any Coderable = { JSONCoders() }
 
   /// Load the variables based on the request.
   public var load: @Sendable (FileType) async throws -> [String: String] = { _ in [:] }
@@ -61,6 +57,8 @@ public struct EnvironmentDependency: Sendable {
   }
 }
 
+struct DecodeError: Error {}
+
 @_spi(Internal)
 extension EnvironmentDependency: DependencyKey {
 
@@ -71,8 +69,7 @@ extension EnvironmentDependency: DependencyKey {
     encoder: JSONEncoder = .init()
   ) -> Self {
     Self(
-      jsonDecoder: { decoder },
-      jsonEncoder: { encoder },
+      coders: { JSONCoders(decoder: decoder, encoder: encoder) },
       load: { file in
         switch file {
         case let .dotEnv(path: path):
@@ -95,6 +92,39 @@ extension EnvironmentDependency: DependencyKey {
   public static let liveValue: EnvironmentDependency = .live()
 }
 
+/// A type that encode and decode values.
+///
+/// This is really just here to override tests with coders that will throw an error,
+/// instead of encoding or decoding data.
+///
+@_spi(Internal)
+public protocol Coderable {
+  func encode<T: Encodable>(_ instance: T) throws -> Data
+  func decode<T: Decodable>(_ type: T.Type, from data: Data) throws -> T
+}
+
+struct JSONCoders: Coderable {
+
+  let decoder: JSONDecoder
+  let encoder: JSONEncoder
+
+  init(
+    decoder: JSONDecoder = .init(),
+    encoder: JSONEncoder = .init()
+  ) {
+    self.decoder = decoder
+    self.encoder = encoder
+  }
+
+  func encode<T>(_ instance: T) throws -> Data where T: Encodable {
+    try encoder.encode(instance)
+  }
+
+  func decode<T>(_ type: T.Type, from data: Data) throws -> T where T: Decodable {
+    try decoder.decode(T.self, from: data)
+  }
+}
+
 private func url(for path: String) -> URL {
   #if os(Linux)
     return URL(fileURLWithPath: path)

Tests/CliClientTests/CliClientTests.swift

@@ -32,6 +32,8 @@ final class CliClientTests: XCTestCase {
         XCTAssertEqual(cliClient.parseMqttClientVersion(string), version)
       }
     }
+
+    XCTAssertEqual(MQTTClient.Version.parseOrDefault(string: nil), .v3_1_1)
   }
 
   func testLogLevelFromEnvironment() {
@@ -98,6 +100,26 @@ final class CliClientTests: XCTestCase {
     }
   }
 
+  func testMakeEnvVarsWithFailingDecoder() async throws {
+    try await withDependencies {
+      $0.environment.coders = { ThrowingDecoder() }
+    } operation: {
+      @Dependency(\.cliClient) var cliClient
+      let envVars = try await cliClient.makeEnvVars(.init())
+      XCTAssertEqual(envVars, EnvVars())
+    }
+  }
+
+  func testMakeEnvVarsWithFailingEncoder() async throws {
+    try await withDependencies {
+      $0.environment.coders = { ThrowingEncoder() }
+    } operation: {
+      @Dependency(\.cliClient) var cliClient
+      let envVars = try await cliClient.makeEnvVars(.init())
+      XCTAssertEqual(envVars, EnvVars())
+    }
+  }
+
   func testFileType() {
     let arguments = [
       (EnvironmentDependency.FileType.dotEnv(path: "test.env"), "test.env"),
@@ -139,12 +161,16 @@ final class CliClientTests: XCTestCase {
 // - MARK: Helper
 
 private func cleanFilePath(_ path: String) -> String {
+  #if os(Linux)
+    return "Tests/CliClientTests/\(path)"
+  #else
     let split = path.split(separator: ".")
     let fileName = split.first!
     let ext = split.last!
     let url = Bundle.module.url(forResource: String(fileName), withExtension: String(ext))!.absoluteString
     let cleaned = url.split(separator: "file://").last!
     return String(cleaned)
+  #endif
 }
 
 extension EnvVars {
@@ -159,3 +185,28 @@ extension EnvVars {
     version: "5.0"
   )
 }
+
+struct ThrowingDecoder: Coderable {
+
+  func encode<T>(_ instance: T) throws -> Data where T: Encodable {
+    try JSONEncoder().encode(instance)
+  }
+
+  func decode<T>(_ type: T.Type, from data: Data) throws -> T where T: Decodable {
+    throw DecodeError()
+  }
+}
+
+struct ThrowingEncoder: Coderable {
+
+  func encode<T>(_ instance: T) throws -> Data where T: Encodable {
+    throw EncodeError()
+  }
+
+  func decode<T>(_ type: T.Type, from data: Data) throws -> T where T: Decodable {
+    try JSONDecoder().decode(T.self, from: data)
+  }
+}
+
+struct DecodeError: Error {}
+struct EncodeError: Error {}