PureXML/Tests/EncodingTests.swift
Mihaela Mihaljevic e4b2e0127d feat(parser): accept raw bytes with UTF-8/UTF-16 encoding detection
Add PureXML.parse(bytes:) and events(bytes:) for raw [UInt8] input. The encoding
is detected following the XML sniff order (BOM first, then the <? byte pattern,
defaulting to UTF-8) and decoded with the Swift standard library only, so the
package stays Foundation-free and portable. UTF-8 and UTF-16 (both byte orders,
with or without a BOM) are supported, the encoding set the XML spec requires.
Malformed input (odd-length UTF-16) raises ParseError.malformedEncoding.

PureXML.Parsing.InputEncoding.detect(_:) exposes the detector. The lint rule
optional_data_string_conversion is disabled because its suggested fix is a
Foundation API this package cannot use. Reimplemented from the documented XML
byte-detection algorithm; no upstream code copied.
2026-06-08 00:52:56 +02:00

58 lines
2.2 KiB
Swift

@testable import PureXML
import Testing
@Suite("Encoding")
struct EncodingTests {
@Test("Detects encodings from the leading bytes")
func test_detect() {
let detect = PureXML.Parsing.InputEncoding.detect
#expect(detect([0xEF, 0xBB, 0xBF, 0x3C]) == .utf8)
#expect(detect([0xFE, 0xFF, 0x00, 0x3C]) == .utf16BigEndian)
#expect(detect([0xFF, 0xFE, 0x3C, 0x00]) == .utf16LittleEndian)
#expect(detect([0x00, 0x3C, 0x00, 0x3F]) == .utf16BigEndian)
#expect(detect([0x3C, 0x00, 0x3F, 0x00]) == .utf16LittleEndian)
#expect(detect(Array("<r/>".utf8)) == .utf8)
}
@Test("Parses UTF-8 bytes, with and without a BOM")
func test_parseUTF8Bytes() throws {
let plain = try PureXML.parse(bytes: Array("<r>hi</r>".utf8))
#expect(rootText(plain) == "hi")
let withBOM = try PureXML.parse(bytes: [0xEF, 0xBB, 0xBF] + Array("<r>hi</r>".utf8))
#expect(rootText(withBOM) == "hi")
}
@Test("Parses UTF-16 bytes in both byte orders")
func test_parseUTF16Bytes() throws {
let bigEndianNode = try PureXML.parse(bytes: utf16("<r>hi</r>", bigEndian: true))
#expect(rootText(bigEndianNode) == "hi")
let littleEndianNode = try PureXML.parse(bytes: utf16("<r>hi</r>", bigEndian: false))
#expect(rootText(littleEndianNode) == "hi")
}
@Test("Odd-length UTF-16 input is rejected as malformed")
func test_malformedUTF16() {
#expect(throws: PureXML.Parsing.ParseError.malformedEncoding) {
_ = try PureXML.parse(bytes: [0xFE, 0xFF, 0x00])
}
}
private func utf16(_ string: String, bigEndian: Bool) -> [UInt8] {
var bytes: [UInt8] = bigEndian ? [0xFE, 0xFF] : [0xFF, 0xFE]
for unit in string.utf16 {
let high = UInt8(unit >> 8)
let low = UInt8(unit & 0xFF)
bytes += bigEndian ? [high, low] : [low, high]
}
return bytes
}
private func rootText(_ node: PureXML.Model.Node) -> String? {
guard case let .document(children) = node else { return nil }
for child in children {
if case let .element(element) = child { return element.text }
}
return nil
}
}