Merge pull request 'Basic implementation' (#3) from develop into master

Reviewed-on: http://code.merlin.local:3000/adan/Conf/pulls/3

Package.swift

@@ -6,20 +6,11 @@ import PackageDescription
 let package = Package(
     name: "Conf",
     products: [
-        .library(name: "Conf", targets: ["Conf"]),
+        .library(name: "Conf", targets: ["Conf"])
-//        .executable(name: "Demo", targets: ["DemoApp"])
     ],
     dependencies: [
     ],
     targets: [
-        .target(
-            name: "DemoApp",
-            dependencies: [
-                "Conf",
-            ]),
-        .testTarget(
-            name: "DemoAppTests",
-            dependencies: ["DemoApp"]),
         .target(
             name: "Conf",
             dependencies: [

Sources/Conf/Config+Load.swift

@@ -0,0 +1,28 @@
+import Foundation
+
+public extension Config {
+    func load(env filename: String) throws {
+        try load(from: DefaultConfigurationProvider(loader: Fetcher.file(filename), parser: Parser.donEnv))
+    }
+
+    func load(env data: Data) throws {
+        try load(from: DefaultConfigurationProvider(loader: Fetcher.direct(data), parser: Parser.donEnv))
+    }
+
+    func load(json filename: String) throws {
+        try load(from: DefaultConfigurationProvider(loader: Fetcher.file(filename), parser: Parser.json))
+    }
+
+    func load(json data: Data) throws {
+        try load(from: DefaultConfigurationProvider(loader: Fetcher.direct(data), parser: Parser.json))
+    }
+
+    func load(plist filename: String) throws {
+        try load(from: DefaultConfigurationProvider(loader: Fetcher.file(filename), parser: Parser.plist))
+    }
+
+    func load(plist data: Data) throws {
+        try load(from: DefaultConfigurationProvider(loader: Fetcher.direct(data), parser: Parser.plist))
+    }
+
+}

Sources/Conf/Config.swift

@@ -0,0 +1,45 @@
+///  Key-value storage that can be filled from multiple sources
+public final class Config {
+    public init(useEnvironment: Bool = false) {
+        isBackedByEnvironment = useEnvironment
+    }
+
+    let isBackedByEnvironment: Bool
+    private let environment = Environment()
+    private var data = [Key: String]()
+
+    func value(for key: Key) -> String? {
+        return data[key] ?? envValue(for: key)
+    }
+
+    func envValue(for key: Key) -> String? {
+        guard isBackedByEnvironment,
+            key.path.count == 1,
+            let variable = key.path.first
+            else { return nil }
+        return environment[variable]
+    }
+
+    func set(value: String?, for key: Key) {
+        data[key] = value
+    }
+
+    public subscript(_ key: Key) -> String? {
+        get { value(for: key) }
+        set { set(value: newValue, for: key) }
+    }
+
+    public subscript<Value>(_ key: Key) -> Value? where Value: LosslessStringConvertible {
+        get { value(for: key).flatMap(Value.init) }
+        set { set(value: newValue?.description, for: key) }
+    }
+
+    public func dump() -> [Key: String] {
+        data
+    }
+
+    public func load(from provider: ConfigurationProvider) throws {
+        try data.merge(provider.configuration(),
+                       uniquingKeysWith: { _, new in new })
+    }
+}

Sources/Conf/ConfigurationError.swift

@@ -0,0 +1,5 @@
+public enum ConfigurationError: Error {
+    case fetch(Error)
+    case parse(Error)
+    case decode(path: Key, value: Any)
+}

Sources/Conf/ConfigurationProvider.swift

@@ -0,0 +1,53 @@
+import Foundation
+
+public protocol ConfigurationProvider {
+    func configuration() throws -> [Key: String]
+}
+
+final class DefaultConfigurationProvider: ConfigurationProvider {
+    typealias Fetcher = () throws -> Data
+    typealias Parser = (Data) throws -> [String: Any]
+
+    init(loader: @escaping Fetcher, parser: @escaping Parser) {
+        self.load = loader
+        self.parse = parser
+    }
+
+    let load: Fetcher
+    let parse: Parser
+
+    func configuration() throws -> [Key: String] {
+        let rawData: Data
+        let parsedData: [String: Any]
+        do {
+            try rawData = load()
+        } catch { throw ConfigurationError.fetch(error) }
+        do {
+            parsedData = try parse(rawData)
+        } catch { throw ConfigurationError.parse(error) }
+        return try decode(currentKey: Key(), object: parsedData)
+    }
+
+    func decode(currentKey: Key, object: Any) throws -> [Key: String] {
+        switch object {
+        case let value as LosslessStringConvertible:
+            return [currentKey: value.description]
+        case let value as [String: LosslessStringConvertible]:
+            return .init(uniqueKeysWithValues:
+                value.map { key, value in
+                    (currentKey.child(key: key), value.description) })
+        case let dictionary as [String: Any]:
+            return try dictionary.map { key, value in
+                try decode(currentKey: currentKey.child(key: key), object: value)
+            }.reduce(into: [Key: String]()) { result, value in
+                result.merge(value) { current, _ in current }
+            }
+        case let array as [LosslessStringConvertible]:
+            return .init(uniqueKeysWithValues:
+                array.enumerated()
+                    .map { ( currentKey.child(key: String($0)), $1.description) })
+        default:
+            throw ConfigurationError.decode(path: currentKey, value: object)
+        }
+    }
+}

Sources/Conf/Environment.swift

@@ -0,0 +1,47 @@
+import Foundation
+
+/// Manages environment variables
+@dynamicMemberLookup
+public struct Environment {
+    public init(info: ProcessInfo = .processInfo) {
+        self.info = info
+    }
+
+    private let info: ProcessInfo
+
+    public func dump() -> [String: String] {
+        info.environment
+    }
+
+    public subscript(_ key: String) -> String? {
+        get { info.environment[key] }
+        nonmutating set (value) {
+            if let raw = value {
+                setenv(key, raw, 1)
+            } else {
+                unsetenv(key)
+            }
+        }
+    }
+
+     public subscript(dynamicMember member: String) -> String? {
+        get { self[member] }
+        nonmutating set {  self[member] = newValue }
+    }
+
+    public subscript<Value>(_ key: String) -> Value? where Value: LosslessStringConvertible {
+        get {
+            let raw: String? = self[key]
+            return raw.flatMap(Value.init)
+        }
+        nonmutating set (value) {
+            self[key] = value?.description
+        }
+    }
+
+    public subscript<Value>(dynamicMember member: String) -> Value? where Value: LosslessStringConvertible {
+        get { self[member] }
+        nonmutating set (value) { self[member] = value }
+    }
+
+}

Sources/Conf/Fetcher.swift

@@ -0,0 +1,19 @@
+import Foundation
+
+/// Namespace for the predefined fetchers
+enum Fetcher { }
+
+extension Fetcher {
+
+    static let direct: (Data) -> DefaultConfigurationProvider.Fetcher = { data in
+       return { data }
+    }
+
+    static let file: (String) -> DefaultConfigurationProvider.Fetcher = { configName in
+        return {
+            let url = URL(fileURLWithPath: configName, isDirectory: false)
+            print(url)
+            return try Data(contentsOf: url)
+        }
+    }
+}

Sources/Conf/Foo.swift

@@ -1,3 +0,0 @@
-public func foo() -> Int {
-    return 42
-}

Sources/Conf/Key.swift

@@ -0,0 +1,48 @@
+/// Configuration key that points to the value
+public struct Key {
+
+    let path: [String]
+
+    public init(_ value: LosslessStringConvertible) {
+        path = [value.description]
+    }
+
+    public init(_ elements: [LosslessStringConvertible]) {
+        path = elements.map(\.description)
+    }
+
+    public init(_ elements: LosslessStringConvertible...) {
+        self.init(elements)
+    }
+
+    func child(key: String) -> Key {
+        Key(path + [key])
+    }
+}
+
+extension Key: Equatable {}
+extension Key: Hashable {}
+
+extension Key: ExpressibleByArrayLiteral {
+    public init(arrayLiteral elements: LosslessStringConvertible...) {
+        self.init(elements)
+    }
+}
+
+extension Key: ExpressibleByStringLiteral {
+    public init(stringLiteral value: String) {
+        self.init(value)
+    }
+}
+
+extension Key: ExpressibleByIntegerLiteral {
+    public init(integerLiteral value: Int) {
+        self.init(value)
+    }
+}
+
+extension Key: CustomStringConvertible {
+    public var description: String {
+        "Key<\(path.description)>"
+    }
+}

Sources/Conf/Parser.swift

@@ -0,0 +1,65 @@
+import Foundation
+
+/// Namespace for the predefined parsers
+enum Parser {
+    struct InvalidFormat: Error { let data: Data }
+}
+
+extension Parser {
+    static let json: DefaultConfigurationProvider.Parser = { data in
+        let object = try JSONSerialization.jsonObject(with: data, options: [])
+        guard let values = object as? [String: Any] else {
+            throw InvalidFormat(data: data)
+        }
+        return values
+    }
+}
+
+extension Parser {
+    static let donEnv: DefaultConfigurationProvider.Parser = { data in
+        func fail() throws -> Never {
+            throw InvalidFormat(data: data)
+        }
+        guard let contents = String(data: data, encoding: .utf8) else { try fail() }
+        var result = [String: String]()
+        let lines  = contents.split(whereSeparator: { $0 == "\n" || $0 == "\r\n" }).lazy
+        for line in lines {
+            // ignore comments
+            if line.starts(with: "#") { continue }
+            // ignore lines that appear empty
+            if line.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty {
+                continue
+            }
+            // extract key and value which are separated by an equals sign
+            let parts = line.split(separator: "=", maxSplits: 1)
+            guard parts.count == 2 else { try fail() }
+            let key = parts[0].trimmingCharacters(in: .whitespacesAndNewlines)
+            var value = parts[1].trimmingCharacters(in: .whitespacesAndNewlines)
+           // remove surrounding quotes from value & convert remove escape character before any embedded quotes
+            if value[value.startIndex] == "\"" && value[value.index(before: value.endIndex)] == "\"" {
+                value.remove(at: value.startIndex)
+                value.remove(at: value.index(before: value.endIndex))
+                value = value.replacingOccurrences(of: "\\\"", with: "\"")
+            }
+            // remove surrounding single quotes from value & convert remove escape character before any embedded quotes
+            if value[value.startIndex] == "'" && value[value.index(before: value.endIndex)] == "'" {
+                value.remove(at: value.startIndex)
+                value.remove(at: value.index(before: value.endIndex))
+                value = value.replacingOccurrences(of: "'", with: "'")
+            }
+            result[key] = value
+        }
+        return result
+
+    }
+}
+
+extension Parser {
+    static let plist: DefaultConfigurationProvider.Parser = { data in
+        let object = try PropertyListSerialization.propertyList(from: data, format: nil)
+        guard let values = object as? [String: Any] else {
+            throw InvalidFormat(data: data)
+        }
+        return values
+    }
+}

Sources/DemoApp/main.swift

@@ -1,3 +0,0 @@
-import Conf
-
-print("Hello, world!")

Tests/ConfTests/ConfigTests.swift

@@ -0,0 +1,72 @@
+import XCTest
+@testable import Conf
+
+final class ConfigTests: XCTestCase {
+
+    var config: Config!
+
+    override func setUpWithError() throws {
+        config = Config()
+    }
+
+    func testEnvironmentuse() {
+        XCTAssertNil(Config(useEnvironment: false)["PATH"])
+        XCTAssertNotNil(Config(useEnvironment: true)["PATH"])
+    }
+
+    func testLoadConfigThrow() {
+        let errorConfigProvider = MockConfigurationProvider(config: [:], error: TestError())
+
+        XCTAssertThrowsError(try config.load(from: errorConfigProvider)) { error in
+            XCTAssertTrue(error is TestError)
+        }
+    }
+
+    func testLoadConfigSuccess() throws {
+        let loader = MockConfigurationProvider(config: ["key": "value"])
+        try config.load(from: loader)
+        XCTAssertEqual(config.dump(), [Key("key"): "value"])
+    }
+
+    func testWrite() {
+        let key: Key = "key"
+        XCTAssertEqual(config.dump(), [:])
+        config.set(value: "value", for: key)
+        XCTAssertEqual(config.dump(), [Key("key"): "value"])
+        config.set(value: nil, for: key)
+        XCTAssertEqual(config.dump(), [:])
+        config.set(value: "another value", for: ["long", "path"])
+        XCTAssertEqual(config.dump(), [Key(["long", "path"]): "another value"])
+
+        config["subscript"] = "subscriptValue"
+        XCTAssertEqual(config.dump()["subscript"], "subscriptValue")
+
+        config["lossless"] = 42
+        XCTAssertEqual(config.dump()["lossless"], "42")
+    }
+
+    func testRead() throws {
+        let loader = MockConfigurationProvider(config: [
+            "string": "value",
+            "int": "42",
+            "double": "23.5"
+        ])
+        try config.load(from: loader)
+        XCTAssertEqual(config["blabla"], nil)
+        XCTAssertEqual(config["string"], "value")
+        XCTAssertEqual(config["int"], "42")
+        XCTAssertEqual(config["int"], 42)
+        XCTAssertEqual(config["double"], "23.5")
+        XCTAssertEqual(config["double"], 23.5)
+    }
+
+}
+
+struct MockConfigurationProvider: ConfigurationProvider {
+    var config: [Key: String]
+    var error: Error?
+    func configuration() throws -> [Key: String] {
+        if let error = self.error { throw error }
+        return config
+    }
+}

Tests/ConfTests/DefaultConfigurationProvider.swift

@@ -0,0 +1,125 @@
+import XCTest
+@testable import Conf
+
+final class CommonConfigurationProviderTests: XCTestCase {
+    func testFetchError() {
+        let fetcher: DefaultConfigurationProvider.Fetcher = { throw TestError() }
+        let parser: DefaultConfigurationProvider.Parser = { _ in [:] }
+        let provider = DefaultConfigurationProvider(loader: fetcher, parser: parser)
+
+        XCTAssertThrowsError(try provider.configuration()) { error in
+            if case let ConfigurationError.fetch(detailError) = error {
+                XCTAssertTrue(detailError is TestError)
+            } else {
+                XCTFail("Invalid error returned \(error)")
+            }
+        }
+    }
+
+    func testParserError() {
+        let fetcher: DefaultConfigurationProvider.Fetcher = { Data() }
+        let parser: DefaultConfigurationProvider.Parser = { _ in throw  TestError() }
+        let provider = DefaultConfigurationProvider(loader: fetcher, parser: parser)
+
+        XCTAssertThrowsError(try provider.configuration()) { error in
+            if case let ConfigurationError.parse(detailError) = error {
+                XCTAssertTrue(detailError is TestError)
+            } else {
+                XCTFail("Invalid error returned \(error)")
+            }
+        }
+    }
+
+    func testDecodeError() {
+        let fetcher: DefaultConfigurationProvider.Fetcher = { Data() }
+        let uuid = UUID()
+        let parser: DefaultConfigurationProvider.Parser = { data in
+            return [
+                "first": "value",
+                "second": uuid
+            ]
+        }
+        let provider = DefaultConfigurationProvider(loader: fetcher, parser: parser)
+
+        XCTAssertThrowsError(try provider.configuration()) { error in
+            if case let ConfigurationError.decode(path: key, value: value) = error {
+                XCTAssertEqual(key, "second")
+                XCTAssertEqual(value as? UUID, uuid)
+            } else {
+                XCTFail("Invalid error returned \(error)")
+            }
+        }
+    }
+
+    func testDataFlow() throws {
+        let data = "string".data(using: .utf8)!
+        let fetcher: DefaultConfigurationProvider.Fetcher = { data }
+        let parser: DefaultConfigurationProvider.Parser = { parserInput in
+            XCTAssertEqual(parserInput, data)
+            return [:]
+        }
+        let provider = DefaultConfigurationProvider(loader: fetcher, parser: parser)
+        let configuration = try provider.configuration()
+        XCTAssertTrue(configuration.isEmpty)
+    }
+
+    func testDecodeValues() throws {
+        let fetcher: DefaultConfigurationProvider.Fetcher = { Data() }
+        let parser: DefaultConfigurationProvider.Parser = { _ in
+            return [ "key": 22]
+        }
+        let provider = DefaultConfigurationProvider(loader: fetcher, parser: parser)
+        let configuration = try provider.configuration()
+        XCTAssertEqual(configuration, ["key": "22"])
+    }
+
+    func testDecodeArray() throws {
+        let fetcher: DefaultConfigurationProvider.Fetcher = { Data() }
+        let parser: DefaultConfigurationProvider.Parser = { _ in
+            return [ "key": ["one", "two"]]
+        }
+        let provider = DefaultConfigurationProvider(loader: fetcher, parser: parser)
+        let configuration = try provider.configuration()
+        let expect: [Key: String] = [
+            Key(["key", "0"]): "one",
+            Key(["key", "1"]): "two"
+        ]
+        XCTAssertEqual(configuration, expect)
+    }
+
+    func testDecodeNestedValues() throws {
+        let fetcher: DefaultConfigurationProvider.Fetcher = { Data() }
+        let parser: DefaultConfigurationProvider.Parser = { _ in
+            return [
+                "key": [ "nested": "value" ],
+                "one": [ "more": [
+                    "deep": "value"
+                    ]
+                ]
+            ]
+        }
+        let provider = DefaultConfigurationProvider(loader: fetcher, parser: parser)
+        let configuration = try provider.configuration()
+        let expect: [Key: String] = [
+            Key(["key", "nested"]): "value",
+            Key(["one", "more", "deep"]): "value"
+        ]
+        XCTAssertEqual(configuration, expect)
+    }
+
+    func testDecodeEmptyValues() throws {
+        let fetcher: DefaultConfigurationProvider.Fetcher = { Data() }
+        let parser: DefaultConfigurationProvider.Parser = { _ in [:] }
+        let provider = DefaultConfigurationProvider(loader: fetcher, parser: parser)
+        let configuration = try provider.configuration()
+        XCTAssertEqual(configuration, [:])
+    }
+
+    func testDecodeEmptyArray() throws {
+        let fetcher: DefaultConfigurationProvider.Fetcher = { Data() }
+        let parser: DefaultConfigurationProvider.Parser = { _ in [ "key": []] }
+        let provider = DefaultConfigurationProvider(loader: fetcher, parser: parser)
+        let configuration = try provider.configuration()
+        XCTAssertEqual(configuration, [:])
+    }
+}

Tests/ConfTests/DotEnvParserTests.swift

@@ -0,0 +1,23 @@
+import XCTest
+@testable import Conf
+
+final class DotEnvParserTests: XCTestCase {
+    func testSuccess() throws {
+        let content = try Resource(name: "valid", type: "env").data()
+        let result = try Parser.donEnv(content)
+        let expect = [
+            "TZ": "Europe/Moscow",
+            "PUID": "1026",
+            "PGID": "100",
+            "IP": "127.0.0.1"
+        ]
+        XCTAssertEqual(result as? [String: String], expect)
+    }
+
+    func testError() throws {
+        let content = try Resource(name: "invalid", type: "env").data()
+        XCTAssertThrowsError(try Parser.donEnv(content)) { error in
+            XCTAssertTrue(error is Parser.InvalidFormat)
+        }
+    }
+}

Tests/ConfTests/EnvironmentTests.swift

@@ -0,0 +1,121 @@
+import XCTest
+@testable import Conf
+
+final class EnvironmentTests: XCTestCase {
+
+    static let sampleValues: [String: String] = [
+        "first": "string",
+        "integer": "1",
+        "float": "2.33",
+        "booleanTrue": "true",
+        "booleanFalse": "false",
+        "YES": "YES"
+    ]
+
+    func testDump() throws {
+        let values = Self.sampleValues
+        let info = ProcessInfo.make(with: values)
+        let env = Environment(info: info)
+
+        let dumped = env.dump()
+
+        XCTAssertEqual(values, dumped)
+    }
+
+    func testRead() throws {
+        let info = ProcessInfo.make(with: Self.sampleValues)
+        let env = Environment(info: info)
+
+        XCTAssertNil(env.blabla)
+        XCTAssertNil(env["blabla"])
+
+        XCTAssertEqual(env.first, "string")
+        XCTAssertNil(env.first as Int?)
+        XCTAssertEqual(env["first"], "string")
+        XCTAssertNil(env["first"] as Int?)
+
+        XCTAssertEqual(env.integer as Int?, 1)
+        XCTAssertEqual(env.integer, "1")
+        XCTAssertEqual(env["integer"] as Int?, 1)
+        XCTAssertEqual(env["integer"], "1")
+
+        XCTAssertEqual(env.float, "2.33")
+        XCTAssertEqual(env.float as Double?, 2.33)
+        XCTAssertEqual(env.float as Float?, 2.33)
+        XCTAssertNil(env.float as Int?)
+        XCTAssertEqual(env["float"], "2.33")
+        XCTAssertEqual(env["float"] as Double?, 2.33)
+        XCTAssertEqual(env["float"] as Float?, 2.33)
+        XCTAssertNil(env["float"] as Int?)
+
+        XCTAssertEqual(env.booleanTrue, "true")
+        XCTAssertEqual(env.booleanTrue as Bool?, true)
+        XCTAssertNil(env.booleanTrue as Int?)
+        XCTAssertEqual(env["booleanTrue"], "true")
+        XCTAssertEqual(env["booleanTrue"] as Bool?, true)
+        XCTAssertNil(env["booleanTrue"] as Int?)
+
+        XCTAssertEqual(env.booleanFalse, "false")
+        XCTAssertEqual(env.booleanFalse as Bool?, false)
+        XCTAssertNil(env.booleanFalse as Int?)
+        XCTAssertEqual(env["booleanFalse"], "false")
+        XCTAssertEqual(env["booleanFalse"] as Bool?, false)
+        XCTAssertNil(env["booleanFalse"] as Int?)
+
+        XCTAssertEqual(env.YES, "YES")
+        XCTAssertNil(env.YES as Bool?)
+    }
+
+    func testAdd() {
+        let env = Environment(info: ProcessInfo.instance)
+
+        XCTAssertNil(env.key1)
+        env.key1 = "value1"
+        XCTAssertEqual(env.key1, "value1")
+
+        XCTAssertNil(env.key2)
+        env["key2"] = "value2"
+        XCTAssertEqual(env.key2, "value2")
+    }
+
+    func testRemove() {
+        let env = Environment(info: ProcessInfo.instance)
+        env.key1 = "value1"
+
+        XCTAssertEqual(env.key1, "value1")
+        env.key1 = nil
+        XCTAssertNil(env.key1)
+
+        env["key2"] = "value2"
+        XCTAssertEqual(env["key2"], "value2")
+        env["key2"] = nil
+        XCTAssertNil(env["key2"])
+    }
+
+    func testUpdate() {
+        let env = Environment(info: ProcessInfo.instance)
+        env.key1 = "value"
+
+        XCTAssertEqual(env.key1, "value")
+        env.key1 = "new value"
+        XCTAssertEqual(env.key1, "new value")
+    }
+
+    func testWrite() {
+        let env = Environment(info: ProcessInfo.instance)
+
+        let int = Int.random(in: Int.min...Int.max)
+        env.int = int
+        XCTAssertEqual(env.int, int)
+
+        let float = Float.random(in: 0...100)
+        env.float = float
+        XCTAssertEqual(env.float, float)
+
+        env.success = true
+        XCTAssertEqual(env.success, true)
+
+        env.failure = false
+        XCTAssertEqual(env.failure, false)
+    }
+}

Tests/ConfTests/FileFetcherTests.swift

@@ -0,0 +1,14 @@
+import XCTest
+@testable import Conf
+
+final class FileFetcherTests: XCTestCase {
+    func testSuccess() throws {
+        let load = Fetcher.file("Tests/Resources/valid.env")
+        _ = try load()
+    }
+
+    func testError() throws {
+        let load = Fetcher.file("file that not exist")
+        XCTAssertThrowsError(try load())
+    }
+}

Tests/ConfTests/FooTests.swift

@@ -1,9 +0,0 @@
-import XCTest
-@testable import Conf
-
-final class FooTests: XCTestCase {
-
-    func testFoo() throws {
-
-    }
-}

Tests/ConfTests/JSONParserTests.swift

@@ -0,0 +1,16 @@
+import XCTest
+@testable import Conf
+
+final class JSONParserTests: XCTestCase {
+    func testSuccess() throws {
+        let content = try Resource(name: "valid", type: "json").data()
+        _ = try Parser.json(content)
+    }
+
+    func testError() throws {
+        let content = try Resource(name: "invalid", type: "json").data()
+        XCTAssertThrowsError(try Parser.json(content)) { error in
+            XCTAssertTrue(error is Parser.InvalidFormat)
+        }
+    }
+}

Tests/ConfTests/KeyTests.swift

@@ -0,0 +1,25 @@
+import XCTest
+@testable import Conf
+
+final class KeyTests: XCTestCase {
+    func testCreation() {
+        let key1: Key = Key()
+        XCTAssertEqual(key1.path, [])
+        let key2: Key = "24"
+        XCTAssertEqual(key2.path, ["24"])
+        let key3: Key = 99
+        XCTAssertEqual(key3.path, ["99"])
+        let key4: Key = Key(23.4)
+        XCTAssertEqual(key4.path, ["23.4"])
+        let key5: Key = Key("some")
+        XCTAssertEqual(key5.path, ["some"])
+        let key6: Key = ["24", 72, 23.4, true]
+        XCTAssertEqual(key6.path, ["24", "72", "23.4", "true"])
+        let key7: Key = Key([1, 2, 3])
+        XCTAssertEqual(key7.path, ["1", "2", "3"])
+    }
+
+    func testChild() {
+        XCTAssertEqual(Key("hello").child(key: "world").path, ["hello", "world"])
+    }
+}

Tests/ConfTests/MockProcessInfo.swift

@@ -0,0 +1,42 @@
+import Foundation
+
+#if os(macOS)
+class MockProcessInfo: ProcessInfo {
+    init(_ env: [String: String]) { self.env = env }
+    var env: [String: String]
+    override var environment: [String: String] { env }
+}
+#endif
+
+extension ProcessInfo {
+    static var instance: ProcessInfo {
+        #if os(macOS)
+        return ProcessInfo()
+        #else
+        return ProcessInfo.processInfo
+        #endif
+    }
+
+    static func make(with env: [String: String]) -> ProcessInfo {
+        #if os(macOS)
+        return MockProcessInfo(env)
+        #else
+        let info = ProcessInfo.instance
+        info.clearEnv()
+        info.set(env: env)
+        return info
+        #endif
+    }
+
+    func clearEnv() {
+        environment.forEach {key, _ in
+            unsetenv(key)
+        }
+    }
+
+    func set(env: [String: String]) {
+        env.forEach { key, value in
+            setenv(key, value, 1)
+        }
+    }
+}

Tests/ConfTests/PlistParserTests.swift

@@ -0,0 +1,16 @@
+import XCTest
+@testable import Conf
+
+final class PlistParserTests: XCTestCase {
+    func testSuccess() throws {
+        let content = try Resource(name: "valid", type: "plist").data()
+        _ = try Parser.plist(content)
+    }
+
+    func testError() throws {
+        let content = try Resource(name: "invalid", type: "plist").data()
+        XCTAssertThrowsError(try Parser.plist(content)) { error in
+            XCTAssertTrue(error is Parser.InvalidFormat)
+        }
+    }
+}

Tests/ConfTests/Resource.swift

@@ -0,0 +1,37 @@
+import Foundation
+
+struct Resource {
+    let name: String
+    let type: String
+    let url: URL
+
+    init(name: String, type: String) {
+        self.name = name
+        self.type = type
+        url = Resource.resourceFolderURL.appendingPathComponent(name).appendingPathExtension(type)
+    }
+}
+
+// MARK: - Content -
+extension Resource {
+    func data() throws -> Data { try Data(contentsOf: url) }
+    func string() throws -> String { try String(contentsOf: url, encoding: .utf8) }
+}
+
+// MARK: - Path helpers -
+extension Resource {
+    //  expected folder structure
+    // <Some folder>
+    //  - <Resources>
+    //      - <resource files>
+    //  - <Some test source folder>
+    //      - <test case files>
+    //      - <this file>
+    static let resourceFolderURL = testsFolderURL
+        .deletingLastPathComponent()
+        .appendingPathComponent(resourceFolder, isDirectory: true)
+        .standardized
+    static let testsFolderURL = sourceFileURL.deletingLastPathComponent()
+    private static let resourceFolder = "Resources"
+    private static let sourceFileURL = URL(fileURLWithPath: #file, isDirectory: false)
+}

Tests/ConfTests/TestError.swift

@@ -0,0 +1 @@
+struct TestError: Error {}

Tests/DemoAppTests/OutputTests.swift

@@ -1,43 +0,0 @@
-import XCTest
-import class Foundation.Bundle
-
-final class OutputTests: 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.
-
-        // Some of the APIs that we use below are available in macOS 10.13 and above.
-        guard #available(macOS 10.13, *) else {
-            return
-        }
-
-        let fooBinary = productsDirectory.appendingPathComponent("DemoApp")
-
-        let process = Process()
-        process.executableURL = fooBinary
-
-        let pipe = Pipe()
-        process.standardOutput = pipe
-
-        try process.run()
-        process.waitUntilExit()
-
-        let data = pipe.fileHandleForReading.readDataToEndOfFile()
-        let output = String(data: data, encoding: .utf8)
-
-        XCTAssertEqual(output, "Hello, world!\n")
-    }
-
-    /// Returns path to the built products directory.
-    var productsDirectory: URL {
-      #if os(macOS)
-        for bundle in Bundle.allBundles where bundle.bundlePath.hasSuffix(".xctest") {
-            return bundle.bundleURL.deletingLastPathComponent()
-        }
-        fatalError("couldn't find the products directory")
-      #else
-        return Bundle.main.bundleURL
-      #endif
-    }
-}

Tests/Resources/invalid.env

@@ -0,0 +1,2 @@
+## Sample invalid env file
+Hello

Tests/Resources/invalid.json

@@ -0,0 +1 @@
+[1, 2, 3]

Tests/Resources/invalid.plist

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<array>
+	<string>one</string>
+	<string>two</string>
+</array>
+</plist>

Tests/Resources/valid.env

@@ -0,0 +1,8 @@
+# Sample env file
+TZ="Europe/Moscow"
+
+IP='127.0.0.1'
+
+# UNIX PUID and PGID, find with: id $USER
+PUID=1026
+PGID=100

Tests/Resources/valid.json

@@ -0,0 +1,11 @@
+{
+    "param": "value",
+    "nested": {
+        "key": "values"
+    },
+    "array": [
+        1,
+        2,
+        3
+    ]
+}

Tests/Resources/valid.plist

@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>CFBundleDevelopmentRegion</key>
+	<string>$(DEVELOPMENT_LANGUAGE)</string>
+	<key>CFBundleExecutable</key>
+	<string>$(EXECUTABLE_NAME)</string>
+	<key>CFBundleIdentifier</key>
+	<string>$(PRODUCT_BUNDLE_IDENTIFIER)</string>
+	<key>CFBundleInfoDictionaryVersion</key>
+	<string>6.0</string>
+	<key>CFBundleName</key>
+	<string>$(PRODUCT_NAME)</string>
+	<key>CFBundlePackageType</key>
+	<string>FMWK</string>
+	<key>CFBundleShortVersionString</key>
+	<string>1.0</string>
+	<key>CFBundleVersion</key>
+	<string>$(CURRENT_PROJECT_VERSION)</string>
+</dict>
+</plist>