https://medium.com/wantedly-engineering/https-medium-com-wantedly-engineering-introducing-page-object-pattern-in-io-74e46c664d26

testSignup.swift

func testSignup() {
    let app = XCUIApplication()

    // Start from welcome page
    app.buttons["Signup"].tap()

    // Move to sign up page
    let emailField = app.textFields["emailField"]
    let passwordField = app.secureTextFields["passwordField"]
    let nameField = app.textFields["nameField"]
    XCTAssert(emailField.exists)
    XCTAssert(passwordField.exists)
    XCTAssert(nameField.exists)

    // Fill email, password and name fields
    emailField.typeText("smith@example.com")
    passwordField.typeText("jg28hwm90iflz")
    nameField.typeText("Smith")


    // Tap "create an account" button
    app.buttons["createAccount"].tap()

    // Move to complete page
    let heading = app.staticTexts["heading"]
    XCTAssert(heading.exists)
    XCTAssertEqual(heading.label, "Welcome, Smith!")

    // Select country
    app.pickers["CountryPicker"]
        .pickerWheels
        .element(boundBy: 0)
        .adjust(toPickerWheelValue: "Japan")

    // ...
}