BundleVersion.swift

struct BundleVersion: Comparable {
    let tuple: (Int, Int, Int)

    init(string: String) {
        let numbers = string.split(separator: ".").compactMap({ Int($0) })

        let major = numbers.count >= 1 ? numbers[0] : 0
        let minor = numbers.count >= 2 ? numbers[1] : 0
        let patch = numbers.count >= 3 ? numbers[2] : 0

        self.tuple = (major, minor, patch)
    }

    static func == (lhs: Self, rhs: Self) -> Bool {
        return lhs.tuple == rhs.tuple
    }

    static func < (lhs: Self, rhs: Self) -> Bool {
        return lhs.tuple < rhs.tuple
    }
}

BundleVersionTests.swift

class BundleVersionTests: XCTestCase {

    func testBasic() {
        XCTAssert(BundleVersion(string: "1").tuple == (1, 0, 0))
        XCTAssert(BundleVersion(string: "2.5.3").tuple == (2, 5, 3))
        XCTAssert(BundleVersion(string: "3.6").tuple == (3, 6, 0))
    }

    func testComparable() {
        XCTAssertLessThan(BundleVersion(string: "1"), BundleVersion(string: "2.5.3"))
        XCTAssertLessThan(BundleVersion(string: "2.5.3"), BundleVersion(string: "3.6"))
        XCTAssertGreaterThan(BundleVersion(string: "4"), BundleVersion(string: "2.5.3"))
    }

}