@testable import PureYAML
import Testing

/// Verifies the ported character-class predicates match libyaml's `IS_*` macros,
/// including end-of-input as `nil` and the multi-byte line breaks.
@Suite("LibYAML Character Class")
struct LibYAMLCharacterClassTests {
    private typealias Classify = PureYAML.Parsing.LibYAML.CharacterClass

    @Test("end of input is Z and a break, nothing else")
    func test_endOfInput() {
        #expect(Classify.isZ(nil))
        #expect(Classify.isBreakZ(nil))
        #expect(Classify.isBlankZ(nil))
        #expect(!Classify.isBreak(nil))
        #expect(!Classify.isBlank(nil))
        #expect(!Classify.isAlpha(nil))
    }

    @Test("blanks are space and tab only")
    func test_blank() {
        #expect(Classify.isSpace(" "))
        #expect(Classify.isTab("\t"))
        #expect(Classify.isBlank(" "))
        #expect(Classify.isBlank("\t"))
        #expect(!Classify.isBlank("\n"))
        #expect(!Classify.isBlank("x"))
    }

    @Test("line breaks include CR, LF, NEL, LS, PS")
    func test_break() {
        for scalar in ["\r", "\n", "\u{85}", "\u{2028}", "\u{2029}"] as [Unicode.Scalar] {
            #expect(Classify.isBreak(scalar))
            #expect(Classify.isBreakZ(scalar))
            #expect(Classify.isBlankZ(scalar))
        }
        #expect(!Classify.isBreak(" "))
        #expect(!Classify.isBreak("x"))
    }

    @Test("alpha is alnum plus underscore and hyphen")
    func test_alpha() {
        for scalar in ["0", "9", "A", "Z", "a", "z", "_", "-"] as [Unicode.Scalar] {
            #expect(Classify.isAlpha(scalar))
        }
        #expect(!Classify.isAlpha("."))
        #expect(!Classify.isAlpha(" "))
        #expect(Classify.isDigit("5"))
        #expect(!Classify.isDigit("a"))
        #expect(Classify.isHex("f"))
        #expect(Classify.isHex("9"))
        #expect(!Classify.isHex("g"))
    }

    @Test("ascii and printable boundaries")
    func test_asciiPrintable() {
        #expect(Classify.isASCII("\u{7F}"))
        #expect(!Classify.isASCII("\u{80}"))
        #expect(Classify.isPrintable("\t"))
        #expect(Classify.isPrintable("A"))
        #expect(Classify.isPrintable("\u{85}"))
        #expect(!Classify.isPrintable("\u{0}"))
        #expect(!Classify.isPrintable("\u{1F}"))
    }
}