UITests全部失败，但不是单独运行时

Question

我编写了5个UITests，每个UITests都与应用程序中的不同部分进行交互。其中3人点按了UIButton的标题标题中的UITableView。第一部分是第一部分的标题，第二部分是第二部分，依此类推。当我单独运行它们时，它们会通过。当我运行所有测试时，它们会失败。

- (void)testFirst {
    XCUIElement *table = self.app.tables.allElementsBoundByIndex[0];
    [[[self.app.tables.otherElements containingType:XCUIElementTypeStaticText identifier:@"Table"] childrenMatchingType:XCUIElementTypeButton].element tap];

    sleep(3);

    XCUIElement *titleField = self.app.textFields[@"Name"];
    [UIPasteboard generalPasteboard].string = @"testName";
    [titleField doubleTap];
    [self.app.menuItems[@"Paste"] tap];
}

- (void)testSecond {
    XCUIElement *table = self.app.tables.allElementsBoundByIndex[0];
    [[[self.app.tables.otherElements containingType:XCUIElementTypeStaticText identifier:@"Chair"] childrenMatchingType:XCUIElementTypeButton].element tap];

    sleep(3);

    XCUIElement *titleField = self.app.textFields[@"Name"];
    [UIPasteboard generalPasteboard].string = @"testName";
    [titleField doubleTap];
    [self.app.menuItems[@"Paste"] tap];
}

- (void)testThird {
    XCUIElement *table = self.app.tables.allElementsBoundByIndex[0];
    [[[self.app.tables.otherElements containingType:XCUIElementTypeStaticText identifier:@"Guy"] childrenMatchingType:XCUIElementTypeButton].element tap];

    sleep(3);

    XCUIElement *titleField = self.app.textFields[@"Name"];
    [UIPasteboard generalPasteboard].string = @"testName";
    [titleField doubleTap];
    [self.app.menuItems[@"Paste"] tap];
}

正如我所说，当我单独运行其中一个时，它们会通过。但是当我全部运行它们时，其中2个或全部3个将在[self.app.menuItems[@"Paste"] tap];或[titleField doubleTap];上失败。我几个小时都在沉溺于此。关于导致这种情况的任何想法？

编辑：我添加了setUp和tearDown方法。

- (void)setUp {
    [super setUp];

    // Put setup code here. This method is called before the invocation of each test method in the class.

    // In UI tests it is usually best to stop immediately when a failure occurs.
    self.continueAfterFailure = NO;
    // UI tests must launch the application that they test. Doing this in setup will make sure it happens for each test method.

    // In UI tests it’s important to set the initial state - such as interface orientation - required for your tests before they run. The setUp method is a good place to do this.

    self.app = [[XCUIApplication alloc] init];

    self.snapshot = [[SnapshotHelper alloc] init];
    [self.snapshot setupSnapshot:self.app];

    [self.app launch];
}

- (void)tearDown {
    // Put teardown code here. This method is called after the invocation of each test method in the class.
    [super tearDown];
}