问模拟和注入ObservableObject

EN

final class SomeState: ObservableObject {
  @Published var someValue: String?
}

final class SomeStateWatcher {
  let someState: SomeState

  var didSetSomeValue: Bool = false
  var lastSomeValue: String?

  private var someValueSubscriber: AnyCancellable?

  init(someState: SomeState) {
    self.someState = someState

    self.someValueSubscriber = self.someState.$someValue
      .sink(receiveValue: { value in 
        self.didSetSomeValue = true
        self.lastSomeValue = value
      })
  }
}

func testDoStuffThatChangesTheLocalSomeStateProperty() {
  someImplementation.doStuffThatChangesTheLocalSomeStateProperty(with: "Fourty2")

  XCTAssertTrue(someStateWatcher.didSetSomeValue, "It should have published someValue")
  XCTAssertEqual(someStateWatcher.lastSomeValue, "Fourty2", "It should have published the correct value)
}