README

mochita lets you write integration tests for your R web applications. You declare an HTTP request and the expectations its response should meet; $perform() then spins up your app on a random local port, sends the request for real, and checks the response with testthat.

Installation

# install.packages("pak")
pak::pak("JulioCollazos64/mochita")

Example

mochita() takes an app definition as understood by httpuv, i.e. a list with a call function that receives a Rook request and returns the response:

app <- list(
  call = function(req) {
    list(
      status = 200L,
      headers = list("Content-Type" = "text/plain"),
      body = paste0("hello, ", req$HTTP_USER_AGENT)
    )
  }
)

Pick an HTTP method, build up the request, declare the expectations and finally $perform() it:

library(mochita)

mochita(app)$get("/")$
  set("User-Agent", "mochita")$
  expect(200)$
  expect("Content-Type", "text/plain")$
  expect("hello, mochita")$
  perform()
#> Test passed with 3 successes 🎉.

Expectations

mochita(app)$get("/")$
  set("User-Agent", "mochita")$
  expect(200)$                          # response status
  expect(200L, "hello, mochita")$       # status and body at once
  expect("Content-Type", "text/plain")$ # a header name/value pair
  expect("hello, mochita")$             # the response body
  perform()

For anything else, pass a function taking the response — a list with status, headers and body — and use any testthat expectation inside:

mochita(app)$get("/")$
  set("User-Agent", "netscape")$
  expect(function(res) {
    testthat::expect_match(res$body, "netscape")
  })$
  perform()

Sending a request body

Use $send() to attach a body to the request, for instance when testing a JSON endpoint:

json_app <- list(
  call = function(req) {
    input <- yyjsonr::read_json_raw(req$rook.input$read())

    body <- yyjsonr::write_json_str(
      list(x = seq_len(input$len)),
      opts = yyjsonr::opts_write_json(auto_unbox = TRUE)
    )

    list(
      status = 200L,
      headers = list("Content-Type" = "application/json"),
      body = body
    )
  }
)

mochita(json_app)$post("/json")$
  set("Accept", "application/json")$
  send('{"len":3}')$
  expect("Content-Type", "application/json")$
  expect(200L, '{"x":[1,2,3]}')$
  perform()
#> Test passed with 3 successes 🎉.

Reusing the app

Passing the app each time is not necessary. If you are testing the same app, assign the result of mochita() once — each method verb starts a fresh request:

req <- mochita(app)

req$get("/")$set("User-Agent", "firefox")$expect("hello, firefox")$perform()
#> Test passed with 1 success 🎉.

req$get("/")$set("User-Agent", "chromium")$expect("hello, chromium")$perform()
#> Test passed with 1 success 😸.

Use in your test suite

Since expectations run through testthat, mochita calls slot directly into your tests/testthat/ files:

describe("GET /", {
  it("greets the user agent", {
    mochita(app)$get("/")$
      set("User-Agent", "mochita")$
      expect(200)$
      expect("hello, mochita")$
      perform()
  })
})