test_that("addMatch errors when dat lacks z or id", {
  dat0 <- data.frame(x = rnorm(6), z = c(1, 1, 0, 0, 0, 0), prc = rep(1L, 6))
  bd <- basicDistance(dat0)
  dat <- bd$dat
  cost <- bd$cost
  id1 <- dat$id[dat$z == 1]
  id2 <- dat$id[dat$z == 0]
  seedM <- blockDesign:::seedMatch(id1[1:2], id2, dat, cost, 0, ncontrols = 1, solver = "rlemon")
  bad_dat <- dat[, setdiff(names(dat), "z"), drop = FALSE]
  expect_error(
    blockDesign:::addMatch(id1, id2, seedM, bad_dat, cost,
      J = 4L, seed_tc = TRUE, solver = "rlemon"
    ),
    "addMatch, z must be"
  )
})

test_that("addMatch extends a seed match (treated–control)", {
  set.seed(1)
  n <- 12L
  dat0 <- data.frame(x = rnorm(n), z = c(rep(1, 4), rep(0, 8)), prc = rep(1L, n))
  bd <- basicDistance(dat0)
  dat <- bd$dat
  cost <- bd$cost
  id1 <- dat$id[dat$z == 1]
  id2 <- dat$id[dat$z == 0]
  seedM <- blockDesign:::seedMatch(id1[1:2], id2, dat, cost, 0, ncontrols = 1, solver = "rlemon")
  am <- blockDesign:::addMatch(
    id1, id2, seedM, dat, cost,
    J = 4L, seed_tc = TRUE, solver = "rlemon"
  )
  expect_s3_class(am, "data.frame")
  expect_true(all(c("mset", "type", "z") %in% names(am)))
  expect_true(nrow(am) >= nrow(seedM))
  expect_equal(levels(am$type), c("seed", "add", "single"))
})

test_that("addMatch extends a seed match (control–treated)", {
  set.seed(2)
  n <- 12L
  dat0 <- data.frame(x = rnorm(n), z = c(rep(1, 4), rep(0, 8)), prc = rep(1L, n))
  bd <- basicDistance(dat0)
  dat <- bd$dat
  cost <- bd$cost
  id1 <- dat$id[dat$z == 0]
  id2 <- dat$id[dat$z == 1]
  seedM <- blockDesign:::seedMatch(id1[1:2], id2, dat, t(cost), 0, ncontrols = 1, solver = "rlemon")
  seedM <- seedM[order(seedM$mset, 1 - seedM$z), ]
  am <- blockDesign:::addMatch(
    id1, id2, seedM, dat, cost,
    J = 4L, seed_tc = FALSE, solver = "rlemon"
  )
  expect_s3_class(am, "data.frame")
  expect_true(all(c("mset", "type", "z") %in% names(am)))
  expect_true(nrow(am) >= nrow(seedM))
  expect_equal(levels(am$type), c("seed", "add", "single"))
})

test_that("addMatch requires J >= 2", {
  set.seed(1)
  n <- 12L
  dat0 <- data.frame(x = rnorm(n), z = c(rep(1, 4), rep(0, 8)), prc = rep(1L, n))
  bd <- basicDistance(dat0)
  dat <- bd$dat
  cost <- bd$cost
  id1 <- dat$id[dat$z == 1]
  id2 <- dat$id[dat$z == 0]
  seedM <- blockDesign:::seedMatch(id1[1:2], id2, dat, cost, 0, ncontrols = 1, solver = "rlemon")
  expect_error(
    blockDesign:::addMatch(
      id1, id2, seedM, dat, cost,
      J = 1L, seed_tc = TRUE, solver = "rlemon"
    ),
    "`J`"
  )
})

test_that("addMatch requires id and z on sdm", {
  set.seed(1)
  n <- 12L
  dat0 <- data.frame(x = rnorm(n), z = c(rep(1, 4), rep(0, 8)), prc = rep(1L, n))
  bd <- basicDistance(dat0)
  dat <- bd$dat
  cost <- bd$cost
  id1 <- dat$id[dat$z == 1]
  id2 <- dat$id[dat$z == 0]
  seedM <- blockDesign:::seedMatch(id1[1:2], id2, dat, cost, 0, ncontrols = 1, solver = "rlemon")
  bad_sdm <- seedM[, setdiff(names(seedM), "id"), drop = FALSE]
  expect_error(
    blockDesign:::addMatch(
      id1, id2, bad_sdm, dat, cost,
      J = 4L, seed_tc = TRUE, solver = "rlemon"
    ),
    "column of sdm"
  )
})