test_that("convertQuad", {

   r1 <-readModelDb("PK_2cmt_no_depot") |>
     addIndirectLin(stim="out") |>
     convertQuad()

   expect_equal(rxode2::modelExtract(r1, "d/dt(R)"),
                "d/dt(R) <- kin - kout * R * (1 + (Ek * Cc + Ek2 * Cc^2))")

    r1 <-readModelDb("PK_2cmt_no_depot") |>
      addDirectLin() |>
      convertQuad()

    expect_equal(rxode2::modelExtract(r1, "effect"),
                "effect <- Ek * Cc + Ek2 * Cc^2")

    r1 <- readModelDb("PK_2cmt_no_depot") |>
     addEffectCmtLin() |>
     convertQuad()

    expect_equal(rxode2::modelExtract(r1, "effect"),
                 "effect <- Ek * Ce + Ek2 * Ce^2")

    f <- function() {
      description<- "PK model with 2 compartments and no depot and linear effect"
      model({
        Ek <- uEk
        cl <- exp(lcl)
        vc <- exp(lvc)
        vp <- exp(lvp)
        q <- exp(lq)
        kel <- cl/vc
        k12 <- q/vc
        k21 <- q/vp
        d/dt(central) <- -kel * central - k12 * central + k21 *
          peripheral1
        d/dt(peripheral1) <- k12 * central - k21 * peripheral1
        Cc <- central/vc
        effect <- Ek * Cc
      })
    }

    r1 <- rxode2::rxode2(f) |>
      convertQuad()

    expect_null(r1$meta$description)
    expect_equal(rxode2::modelExtract(r1, "effect"),
                 "effect <- Ek * Cc + Ek2 * Cc^2")

    expect_equal(r1$theta, c(uEk2 = 0.1))

    expect_equal(r1$iniDf$label,
                 "untransformed quadratic slope (Ek2)")

})