test_that("rename() works for one column", {
  df <- data.table(x = c(1,1,1), y = c(2,2,2), z = c("a", "a", "b"))
  df <- df %>%
    rename(new_x = x)

  expect_named(df, c("new_x", "y", "z"))
})

test_that("rename() doesn't modify-by-reference", {
  df <- data.table(x = c(1,1,1), y = c(2,2,2), z = c("a", "a", "b"))
  df %>%
    rename(new_x = x)

  expect_named(df, c("x", "y", "z"))
})

test_that("rename() works for one column w/ data.frame", {
  df <- data.frame(x = c(1,1,1), y = c(2,2,2), z = c("a", "a", "b"))
  df <- df %>%
    rename(new_x = x)

  expect_named(df, c("new_x", "y", "z"))
})

test_that("rename() works for spaced column names", {
  df <- data.table(`test spaced column` = 1:3, y = c(2,2,2), z = c("a", "a", "b"))
  df <- df %>%
    rename(new_name = `test spaced column`)

  expect_named(df, c("new_name", "y", "z"))
})

test_that("rename() works for multiple columns", {
  df <- data.table(x = c(1,1,1), y = c(2,2,2), z = c("a", "a", "b"))
  df <- df %>%
    rename(new_x = x,
            new_y = y)

  expect_named(df, c("new_x", "new_y", "z"))
})

test_that("rename() works by column position", {
  df <- data.table(x = c(1,1,1), y = c(2,2,2), z = c("a", "a", "b"))
  df <- df %>%
    rename(new_x = 1,
           new_y = 2)

  expect_named(df, c("new_x", "new_y", "z"))
})

test_that("rename_with() works for all variables", {
  df <- data.table(x = c(1,1,1), y = c(2,2,2))
  df <- df %>%
    rename_with(~ paste0(.x, "_append"))

  expect_named(df, c("x_append", "y_append"))
})

test_that("rename_with() doesn't modify by reference", {
  df <- data.table(x = c(1,1,1), y = c(2,2,2))
  df %>%
    rename_with(~ paste0(.x, "_append"))

  expect_named(df, c("x", "y"))
})

test_that("rename_with() works for all variables w/ data.frame", {
  df <- data.frame(x = c(1,1,1), y = c(2,2,2))
  df <- df %>%
    rename_with(~ paste0(.x, "_append"))

  expect_named(df, c("x_append", "y_append"))
})

test_that("rename_with() works with predicate", {
  df <- data.table(x = c(1,1,1), y = c(2,2,2), z = c("a", "a", "b"))
  df <- df %>%
    rename_with(~ paste0(.x, "_character"), where(is.character))

  expect_named(df, c("x","y","z_character"))
})

test_that("rename_with() works with twiddle", {
  df <- data.table(x_start = c(1,1,1), end_x = c(2,2,2), z = c("a", "a", "b"))
  anon_df <- df %>%
    rename_with(function(.x) paste0(.x, "_append"), c(starts_with("x")))
  twiddle_df <- df %>%
    rename_with(~ paste0(.x, "_append"), c(starts_with("x")))

  expect_equal(anon_df, twiddle_df)
})

test_that("can make a custom function with quosures", {
  df <- data.table(x = c(1,1,1), y = c(2,2,2), z = c("a", "a", "b"))

  rename_fn <- function(data, new_name, old_name) {
    data %>%
      rename({{ new_name }} := {{ old_name }})
  }

  df <- df %>%
    rename_fn(new_x, x)

  expect_named(df, c("new_x", "y", "z"))
})

test_that("works with a grouped_tt", {
  df <- tidytable(x = 1, y = 2, z = 3) %>%
    group_by(x)

  res <- df %>%
    rename(new_x = x,
           new_y = y)

  expect_named(res, c("new_x", "new_y", "z"))
  expect_equal(group_vars(res), "new_x")
  expect_true(is_grouped_df(res))
})