feat: More cli client tests and documentation.

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 {
-  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)
+  #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 {}