# ------------------------------------------------------------------------------
# funKeywords
# ------------------------------------------------------------------------------
# Voraussetzung: scan() und file.show() haben NULL-Bindings im Package
# (R/utils-mockable.R), help.search() ist via @importFrom utils importiert.

test_that("funKeywords without topic calls file.show", {
  called_with <- NULL
  local_mocked_bindings(
    file.show = function(f) { called_with <<- f }
  )
  funKeywords()
  expect_true(grepl("KEYWORDS", called_with))
})

test_that("funKeywords returns keywords for known topic", {
  local_mocked_bindings(
    scan = function(...) {
      c("math&Arithmetic")   # kein Leerzeichen, exakt ein Token nach gsub
    },
    help.search = function(keyword, ...) {
      matches <- if (keyword == "math")
        data.frame(topic = "mean", Package = "base", stringsAsFactors = FALSE)
      else
        data.frame(topic = character(0), Package = character(0),
                   stringsAsFactors = FALSE)
      structure(list(matches = matches), class = "hsearch")
    }
  )
  res <- funKeywords("mean")
  expect_true("math" %in% res)
})

test_that("funKeywords returns NULL/empty for unknown topic", {
  local_mocked_bindings(
    scan = function(...) c("math&Arithmetic"),
    help.search = function(...) {
      structure(
        list(matches = data.frame(topic = character(0),
                                  stringsAsFactors = FALSE)),
        class = "hsearch"
      )
    }
  )
  res <- funKeywords("nonexistent_fn_xyz")
  expect_true(length(res) == 0)   # NULL oder character(0) — beide akzeptiert
})

test_that("funKeywords accepts string topic", {
  local_mocked_bindings(
    scan = function(...) {
      c("math & arith & Arithmetic")
    },
    help.search = function(keyword, ...) {
      matches <- data.frame(topic = "mean", Package = "base",
                            stringsAsFactors = FALSE)
      structure(list(matches = matches), class = "hsearch")
    }
  )
  res_sym <- funKeywords(mean)
  res_str <- funKeywords("mean")
  expect_equal(res_sym, res_str)
})