tests/testthat/test-persistent_chat_ellmer.R

In tidyprompt: Prompt Large Language Models and Enhance Their Functionality

# Tests for persistent_chat ellmer state sync

test_that("persistent_chat syncs ellmer_chat after each turn", {
  skip_if_not_installed("ellmer")

  call_count <- 0L

  fake_chat <- new.env(parent = emptyenv())
  fake_chat$chat <- function(...) {
    call_count <<- call_count + 1L
    paste0("reply-", call_count)
  }
  fake_chat$clone <- function() {
    copy <- new.env(parent = emptyenv())
    copy$chat <- fake_chat$chat
    copy$clone <- fake_chat$clone
    copy$set_turns <- fake_chat$set_turns
    copy$get_turns <- fake_chat$get_turns
    copy$stream <- NULL
    copy$.synced_marker <- call_count
    copy
  }
  fake_chat$set_turns <- function(turns) {
    fake_chat
  }
  fake_chat$get_turns <- function() list()
  fake_chat$stream <- NULL
  fake_chat$.synced_marker <- 0L

  provider <- llm_provider_ellmer(fake_chat, verbose = FALSE)
  provider$parameters$stream <- FALSE

  pc <- `persistent_chat-class`$new(
    llm_provider = provider,
    chat_history = NULL
  )

  # First turn
  res1 <- pc$chat("hello", verbose = FALSE)
  # The ellmer_chat from the response should now be stored on the provider.
  expect_false(is.null(res1$ellmer_chat))
  # The provider's ellmer_chat should have been updated to the returned one.
  expect_identical(pc$llm_provider$ellmer_chat, res1$ellmer_chat)

  # Second turn
  res2 <- pc$chat("world", verbose = FALSE)
  expect_identical(pc$llm_provider$ellmer_chat, res2$ellmer_chat)
  # Chat history should span both turns (system included or not, at least
  # user + assistant for each).
  expect_true(nrow(pc$chat_history) >= 4L)
})

test_that("persistent_chat replays native tool results on follow-up turns", {
  skip_if_no_ellmer_turn_classes()

  fake_chat <- fake_ellmer_chat()
  fake_chat$chat <- function(...) {
    args <- list(...)
    fake_chat$last_method <- list(
      method = "chat",
      args = args,
      turns = fake_chat$turns
    )

    prompt <- paste(vapply(args, as.character, character(1)), collapse = "")

    if (identical(prompt, "call tool")) {
      request <- ellmer::ContentToolRequest(
        id = "call-1",
        name = "get_secret_number",
        arguments = list(input = 123)
      )

      fake_chat$turns <- c(
        fake_chat$turns,
        list(
          ellmer::UserTurn(list(ellmer::ContentText("call tool"))),
          ellmer::AssistantTurn(list(request)),
          ellmer::UserTurn(list(
            ellmer::ContentToolResult(value = "42", request = request)
          )),
          ellmer::AssistantTurn(list(ellmer::ContentText("The result is 42.")))
        )
      )

      return("The result is 42.")
    }

    fake_chat$turns <- c(
      fake_chat$turns,
      list(
        ellmer::UserTurn(list(ellmer::ContentText(prompt))),
        ellmer::AssistantTurn(list(ellmer::ContentText("follow-up reply")))
      )
    )

    "follow-up reply"
  }

  provider <- llm_provider_ellmer(
    fake_chat,
    parameters = list(stream = FALSE),
    verbose = FALSE
  )

  pc <- `persistent_chat-class`$new(
    llm_provider = provider,
    chat_history = NULL
  )

  invisible(pc$chat("call tool", verbose = FALSE))
  res <- pc$chat("what was the tool result?", verbose = FALSE)

  prior_turns <- res$ellmer_chat$last_method$turns

  expect_length(prior_turns, 3)
  expect_equal(
    vapply(prior_turns, function(turn) turn@role, character(1)),
    c(
      "user",
      "user",
      "assistant"
    )
  )
  expect_true(any(grepl(
    "ContentToolResult",
    class(prior_turns[[2]]@contents[[1]])
  )))
  expect_equal(prior_turns[[3]]@contents[[1]]@text, "The result is 42.")
})