Encapsulate common testing code into one function but have the failures/successes show on the line that called the helper function. From Tim Vermeulenon iosdevelopers.io slack

share test code

func shared(value: Int, file: StaticString = #file, line: UIInt = #line) {
  XCTAssert(value > 10, "value not greater than 10", file: file, line: line)
  XCTAssert(value < 20, "value not less than 20", file: file, line: line)
}

func testFoo() {
  shared(value: 15) // will pass
}

func testBar() {
  shared(value: 25) // will fail
}