feat: Working on configuration client

Tests/ConfigurationClientTests/ConfigurationClientTests.swift

@@ -0,0 +1,58 @@
+import ConfigurationClient
+import Dependencies
+import Foundation
+import Testing
+
+@Suite("ConfigurationClientTests")
+struct ConfigurationClientTests {
+
+  @Test
+  func codable() async throws {
+    try await run {
+      @Dependency(\.configurationClient) var configurationClient
+      @Dependency(\.coders) var coders
+
+      let configuration = Configuration.customPreRelease
+      let encoded = try coders.jsonEncoder().encode(configuration)
+      let decoded = try coders.jsonDecoder().decode(Configuration.self, from: encoded)
+
+      #expect(decoded == configuration)
+
+      let tomlEncoded = try coders.tomlEncoder().encode(configuration)
+      let tomlDecoded = try coders.tomlDecoder().decode(
+        Configuration.self,
+        from: tomlEncoded
+      )
+      #expect(tomlDecoded == configuration)
+    }
+  }
+
+  @Test(arguments: ["foo", ".foo"])
+  func configurationFile(fileName: String) {
+    for ext in ["toml", "json", "bar"] {
+      let file = ConfigruationFile(url: URL(filePath: "\(fileName).\(ext)"))
+      switch ext {
+      case "toml":
+        #expect(file == .toml(URL(filePath: "\(fileName).toml")))
+      case "json":
+        #expect(file == .json(URL(filePath: "\(fileName).json")))
+      default:
+        #expect(file == nil)
+      }
+    }
+  }
+
+  func run(
+    setupDependencies: @escaping (inout DependencyValues) -> Void = { _ in },
+    operation: () async throws -> Void
+  ) async throws {
+    try await withDependencies {
+      $0.coders = .liveValue
+      $0.fileClient = .liveValue
+      $0.configurationClient = .liveValue
+      setupDependencies(&$0)
+    } operation: {
+      try await operation()
+    }
+  }
+}