suffix_tests.nct

//! Owned UTF-8 suffix-removal contract tests.

see ./index.nct

test pop_removes_complete_scalars_without_reallocating {
    var text = String.copy("Aλ😀")
    let capacity = text.capacity()
    let face = text.pop() otherwise {
        return error.new("std.string.test", "final scalar was absent")
    }
    let lambda = text.pop() otherwise {
        return error.new("std.string.test", "middle scalar was absent")
    }
    let ascii = text.pop() otherwise {
        return error.new("std.string.test", "first scalar was absent")
    }
    if face != '😀' || lambda != 'λ' || ascii != 'A' {
        return error.new("std.string.test", "pop changed scalar order")
    }
    if text.capacity() != capacity || (&text as &str) != "" {
        return error.new("std.string.test", "pop changed capacity or remaining text")
    }
    let _extra = text.pop() otherwise { return }
    return error.new("std.string.test", "empty String produced a scalar")
}

test truncate_accepts_boundaries_and_preserves_capacity {
    var text = String.copy("Aλ😀")
    let capacity = text.capacity()
    text.truncate(3)?
    if (&text as &str) != "Aλ" || text.capacity() != capacity {
        return error.new("std.string.test", "boundary truncation changed storage")
    }
    text.truncate(100)?
    if (&text as &str) != "Aλ" {
        return error.new("std.string.test", "oversized truncation changed text")
    }
    text.truncate(0)?
    if (&text as &str) != "" || text.capacity() != capacity {
        return error.new("std.string.test", "zero truncation changed capacity")
    }
    return
}

test truncate_failure_leaves_the_string_unchanged {
    var text = String.copy("éx")
    let capacity = text.capacity()
    text.truncate(1) catch failure {
        if !failure.has_code("std.string.not_char_boundary") {
            return error.new("std.string.test", "truncate returned the wrong error")
        }
        if (&text as &str) != "éx" || text.capacity() != capacity {
            return error.new("std.string.test", "failed truncate changed the String")
        }
        return
    }
    return error.new("std.string.test", "non-boundary truncation succeeded")
}