expectTestDecl

fn expectTestDecl(p: *Parse) Error!Node.Index {
    const test_token = p.assertToken(.keyword_test);
    const name_token: OptionalTokenIndex = switch (p.tokenTag(p.tok_i)) {
        .string_literal, .identifier => .fromToken(p.nextToken()),
        else => .none,
    };
    const block_node = try p.parseBlock() orelse return p.fail(.expected_block);
    return p.addNode(.{
        .tag = .test_decl,
        .main_token = test_token,
        .data = .{ .opt_token_and_node = .{
            name_token,
            block_node,
        } },
    });
}