SwiftEval: Load tests bundle if exists. (johnno1962#66)

Previously, when running tests through injection, if the test would have
depended upon a symbol that's in the tests bundle, it would give an
undefined symbol error. This commit solves this by loading the tests
bundle if it exists, which allows for much better support when loading
new test files through injection.

Sources/HotReloading/SwiftEval.swift

@@ -5,7 +5,7 @@
 // Created by John Holdsworth on 02/11/2017.
 // Copyright © 2017 John Holdsworth. All rights reserved.
 //
-// $Id: //depot/HotReloading/Sources/HotReloading/SwiftEval.swift#156 $
+// $Id: //depot/HotReloading/Sources/HotReloading/SwiftEval.swift#157 $
 //
 // Basic implementation of a Swift "eval()" including the
 // mechanics of recompiling a class and loading the new
@@ -912,9 +912,42 @@ public class SwiftEval: NSObject {
  }
  }()
 
+ lazy var loadTestsBundle: () = {
+ do {
+ guard let testsBundlePath = try testsBundlePath() else {
+ debug("Tests bundle wasn't found - did you run the tests target before running the application?")
+ return
+ }
+ guard let bundle = Bundle(path: testsBundlePath), bundle.load() else {
+ debug("Failed loading tests bundle")
+ return
+ }
+ } catch {
+ debug("Error while searching for the tests bundle: \(error)")
+ return
+ }
+ }()
+
+ func testsBundlePath() throws -> String? {
+ guard let pluginsDirectory = Bundle.main.path(forResource: "PlugIns", ofType: nil) else {
+ return nil
+ }
+
+ let bundlePaths: [String] = try FileManager.default.contentsOfDirectory(atPath: pluginsDirectory)
+ .filter { $0.hasSuffix(".xctest") }
+ .map { directoryName in
+ return "\(pluginsDirectory)/\(directoryName)"
+ }
+ if bundlePaths.count > 1 {
+ debug("Found more than one tests bundle, using the first one")
+ }
+ return bundlePaths.first
+ }
+
  @objc func loadAndInject(tmpfile: String, oldClass: AnyClass? = nil)
  throws -> [AnyClass] {
  _ = loadXCTest
+ _ = loadTestsBundle
 
  print("\(APP_PREFIX)Loading .dylib ...")
  // load patched .dylib into process with new version of class