@testable import PureYAML
import Testing

/// Verifies the ported reader iterates Unicode scalars with libyaml's mark and
/// `SKIP` / `SKIP_LINE` semantics: CR and LF are distinct scalars, a CR+LF pair
/// is one line break, and the column is 0-based.
@Suite("LibYAML Reader")
struct LibYAMLReaderTests {
    @Test("peek and skip advance the column scalar by scalar")
    func test_peekAndSkip() {
        var reader = PureYAML.Parsing.LibYAML.Reader("ab")
        #expect(reader.peek() == "a")
        #expect(reader.peek(1) == "b")
        #expect(reader.peek(2) == nil)
        reader.skip()
        #expect(reader.peek() == "b")
        #expect(reader.column == 1)
        #expect(reader.line == 0)
        reader.skip()
        #expect(reader.isAtEnd)
        #expect(reader.peek() == nil)
    }

    @Test("skipLine starts a new line and resets the column")
    func test_skipLineLF() {
        var reader = PureYAML.Parsing.LibYAML.Reader("a\nb")
        reader.skip()
        reader.skipLine()
        #expect(reader.line == 1)
        #expect(reader.column == 0)
        #expect(reader.peek() == "b")
    }

    @Test("a CR+LF pair is a single line break")
    func test_skipLineCRLF() {
        var reader = PureYAML.Parsing.LibYAML.Reader("a\r\nb")
        reader.skip()
        // CR and LF are distinct scalars but one break.
        #expect(reader.peek() == "\r")
        #expect(reader.peek(1) == "\n")
        reader.skipLine()
        #expect(reader.line == 1)
        #expect(reader.column == 0)
        #expect(reader.peek() == "b")
    }
}