testthat::test_that("Joining two identical qenvs outputs the same object", {
  q1 <- eval_code(qenv(), quote(iris1 <- iris))
  q2 <- q1

  q <- c(q1, q2)

  testthat::expect_equal(q@.xData, q1@.xData)
  testthat::expect_identical(get_code(q), "iris1 <- iris")
})

testthat::test_that("Joining two independent qenvs results in object having combined code and environments", {
  q1 <- eval_code(qenv(), quote(iris1 <- iris))
  q2 <- eval_code(qenv(), quote(mtcars1 <- mtcars))

  q <- c(q1, q2)

  testthat::expect_equal(q@.xData, list2env(list(iris1 = iris, mtcars1 = mtcars)))
  testthat::expect_identical(get_code(q), "iris1 <- iris\nmtcars1 <- mtcars")
})

testthat::test_that("Joined qenv does not duplicate common code", {
  q1 <- eval_code(qenv(), code = expression(iris1 <- iris, mtcars1 <- mtcars))
  q2 <- q1
  q2 <- eval_code(q2, quote(mtcars2 <- mtcars))

  q <- c(q1, q2)
  testthat::expect_identical(get_code(q), "iris1 <- iris\nmtcars1 <- mtcars\nmtcars2 <- mtcars")
  testthat::expect_equal(
    get_env(q),
    list2env(list(
      iris1 = iris,
      mtcars1 = mtcars,
      mtcars2 = mtcars
    ))
  )
})

testthat::test_that("Not able to join two qenvs if any of the shared objects changed", {
  q1 <- eval_code(qenv(), expression(iris1 <- iris, iris2 <- iris))
  q2 <- eval_code(qenv(), quote(iris1 <- head(iris)))
  testthat::expect_error(c(q1, q2), "Not possible to join qenv objects")
})

testthat::test_that("join does not duplicate code but adds only extra code", {
  q1 <- eval_code(qenv(), expression(iris1 <- iris, mtcars1 <- mtcars))
  q2 <- q1
  q1 <- eval_code(q1, quote(iris2 <- iris))
  q2 <- eval_code(q2, quote(mtcars2 <- mtcars))

  q <- c(q1, q2)

  testthat::expect_identical(
    get_code(q),
    c("iris1 <- iris\nmtcars1 <- mtcars\niris2 <- iris\nmtcars2 <- mtcars")
  )

  testthat::expect_equal(
    q@.xData,
    list2env(list(iris1 = iris, iris2 = iris, mtcars1 = mtcars, mtcars2 = mtcars))
  )
})

testthat::test_that("Not possible to join qenvs which share some code when one of the shared object was modified", {
  q1 <- eval_code(qenv(), code = expression(iris1 <- iris, mtcars1 <- mtcars))
  q2 <- q1
  q1 <- eval_code(q1, quote(iris2 <- iris))
  q2 <- eval_code(q2, quote(mtcars1 <- head(mtcars)))

  testthat::expect_error(c(q1, q2), "Following object\\(s\\) have been modified:\n -  mtcars1")
})

testthat::test_that("qenv objects are mergeable if they don't share any code (identified by id)", {
  q1 <- eval_code(qenv(), code = quote(a1 <- 1))
  q2 <- eval_code(qenv(), code = quote(a1 <- 1))
  cq <- c(q1, q2)
  testthat::expect_equal(cq@.xData, list2env(list(a1 = 1)))
  testthat::expect_identical(get_code(cq), "a1 <- 1\na1 <- 1")
})

testthat::test_that("qenv objects are mergeable if they share common initial qenv elements", {
  q1 <- eval_code(qenv(), code = quote(a1 <- 1)) # id 1
  q2 <- eval_code(q1, quote(b1 <- 2)) # id 1 and 2
  q1 <- eval_code(q1, quote(a2 <- 3)) # id 1 and 3

  cq <- c(q1, q2)
  testthat::expect_equal(cq@.xData, list2env(list(a1 = 1, b1 = 2, a2 = 3)))
  testthat::expect_identical(get_code(cq), "a1 <- 1\na2 <- 3\nb1 <- 2")
})

testthat::test_that(
  "qenv objects aren't mergeable if they share common qenv elements proceeded with some other code",
  {
    q1 <- eval_code(qenv(), code = quote(a1 <- 1))
    q2 <- eval_code(qenv(), code = quote(b1 <- 2))
    q_common <- eval_code(qenv(), quote(c1 <- 3))
    q1 <- c(q1, q_common)
    q2 <- c(q2, q_common)
    testthat::expect_error(c(q1, q2), "these objects cannot be joined")
  }
)

testthat::test_that("qenv objects are not mergable if they have multiple common streaks", {
  q_common1 <- eval_code(qenv(), code = quote(c1 <- 1))
  q_common2 <- eval_code(qenv(), code = quote(c2 <- 2))

  q1 <- eval_code(q_common1, quote(a1 <- 3))
  q1 <- c(q1, q_common2) # c1, a1, c2
  q2 <- c(q_common1, q_common2) # c1, c2

  testthat::expect_error(c(q1, q2), "it's impossible to determine the evaluation's order")
})


testthat::test_that("joining with a qenv.error object returns the qenv.error object", {
  q1 <- eval_code(qenv(), quote(x <- 1))
  error_q <- eval_code(qenv(), quote(y <- w))
  error_q2 <- eval_code(qenv(), quote(z <- w))

  testthat::expect_s3_class(c(q1, error_q), "qenv.error")
  testthat::expect_s3_class(c(error_q, error_q2), "qenv.error")
  testthat::expect_s3_class(c(error_q, q1), "qenv.error")

  # if joining two qenv.error objects keep the first
  testthat::expect_equal(c(error_q, error_q2), error_q)
})

testthat::test_that("Joining two independent qenvs with warnings results in object having combined warnings", {
  q1 <- eval_code(qenv(), "warning('This is warning 1')")
  q2 <- eval_code(qenv(), "warning('This is warning 2')")

  q <- c(q1, q2)

  testthat::expect_equal(
    unname(get_code_attr(q, "warning")),
    c(
      "> This is warning 1\n",
      "> This is warning 2\n"
    )
  )
})

testthat::test_that("Joining two independent qenvs with messages results in object having combined messages", {
  q1 <- eval_code(qenv(), "message('This is message 1')")
  q2 <- eval_code(qenv(), "message('This is message 2')")

  q <- c(q1, q2)

  testthat::expect_equal(
    unname(get_code_attr(q, "message")),
    c(
      "> This is message 1\n",
      "> This is message 2\n"
    )
  )
})