Extract key importing logic and put it into separate class

passKitTests/Helpers/KeyFileManagerTest.swift

@@ -0,0 +1,49 @@
+//
+//  KeyFileManagerTest.swift
+//  passKitTests
+//
+//  Created by Danny Moesch on 01.07.19.
+//  Copyright © 2019 Bob Sun. All rights reserved.
+//
+
+import XCTest
+
+@testable import passKit
+
+class KeyFileManagerTest: XCTestCase {
+    private static let filePath = URL(fileURLWithPath: NSTemporaryDirectory()).appendingPathComponent("test.txt").path
+    private static let keyFileManager = KeyFileManager(keyType: .PUBLIC, keyPath: filePath) { _, _ in }
+
+    override func tearDown() {
+        try? FileManager.default.removeItem(atPath: KeyFileManagerTest.filePath)
+        super.tearDown()
+    }
+
+    func testImportKeyAndDeleteFile() throws {
+        let fileContent = "content".data(using: .ascii)
+        var storage: [String: Data] = [:]
+        let keyFileManager = KeyFileManager(keyType: .PRIVATE, keyPath: KeyFileManagerTest.filePath) { storage[$1] = $0 }
+
+        FileManager.default.createFile(atPath: KeyFileManagerTest.filePath, contents: fileContent, attributes: nil)
+        try keyFileManager.importKeyAndDeleteFile()
+
+        XCTAssertFalse(FileManager.default.fileExists(atPath: KeyFileManagerTest.filePath))
+        XCTAssertTrue(storage[PgpKeyType.PRIVATE.getKeychainKey()] == fileContent)
+    }
+
+    func testErrorReadingFile() throws {
+        XCTAssertThrowsError(try KeyFileManagerTest.keyFileManager.importKeyAndDeleteFile()) {
+            XCTAssertEqual($0 as! AppError, AppError.ReadingFile("test.txt"))
+        }
+    }
+
+    func testFileExists() {
+        FileManager.default.createFile(atPath: KeyFileManagerTest.filePath, contents: nil, attributes: nil)
+
+        XCTAssertTrue(KeyFileManagerTest.keyFileManager.doesKeyFileExist())
+    }
+
+    func testFileDoesNotExist() {
+        XCTAssertFalse(KeyFileManagerTest.keyFileManager.doesKeyFileExist())
+    }
+}