Testing reactivity: Simulated time

5. testServer uses simulated time that you control, rather than the actual computer time.

server <- function(input, output, session){
  rv <- reactiveValues(x = 0)

  observe({
    # Cause the observer to invalidate every 0.1 second
    invalidateLater(100)
    isolate(rv$x <- rv$x + 1)
  })
}


testServer(server, {
  expect_equal(rv$x, 0)
  Sys.sleep(0.1)
  expect_equal(rv$x, 1)
})
#> Error: rv$x (`actual`) not equal to 1 (`expected`).
#>
#>   `actual`: 0
#> `expected`: 1