Test that an HTTP request is made with a header — expect_request

This expectation checks that HTTP headers (and potentially header values) are present in a request. It works both in the mock HTTP contexts and on "live" HTTP requests.

expect_request_header(
  expr,
  ...,
  fixed = FALSE,
  ignore.case = FALSE,
  perl = FALSE,
  useBytes = FALSE
)

Arguments

expr: Code to evaluate
...: Named headers to match. Values should either be a string (length-1 character), which will be passed to testthat::expect_match(), or NULL to assert that the named header is not present in the request. To assert that a header is merely present in the request, without asserting anything about its contents, provide an empty string (""). Header names are always case-insensitive; header values will be matched using the following parameters:
fixed: logical. If TRUE, pattern is a string to be matched as is. Overrides all conflicting arguments.
ignore.case: if FALSE, the pattern matching is case sensitive and if TRUE, case is ignored during matching.
perl: logical. Should Perl-compatible regexps be used?
useBytes: logical. If TRUE the matching is done byte-by-byte rather than character-by-character. See ‘Details’.

Value

The value of expr if there are no expectation failures

Examples

if (FALSE) {

library(httr2)
expect_request_header(
  request("http://httpbin.org") %>%
    req_headers(Accept = "image/png") %>%
    req_perform(),
  accept = "image/png",
  `x-fake-header` = NULL
)
expect_request_header(
  request("http://httpbin.org") %>%
    req_headers(Accept = "image/png") %>%
    req_perform(),
  accept = ""
)
}