Testing reactivity: flushReact method

8. If your module functions recives reactives as additinal arguments, you will need to use the session$flushReact() method to update the related outputs.

summaryServer <- function(id, var) {
  stopifnot(is.reactive(var))
  
  moduleServer(id, function(input, output, session) {
    range_val <- reactive(range(var(), na.rm = TRUE))
    output$min <- renderText(range_val()[[1]])
    output$max <- renderText(range_val()[[2]])
    output$mean <- renderText(mean(var()))
  })
}

test_that("output updates when reactive input changes", {
  x <- reactiveVal()
  testServer(summaryServer, args = list(var = x), {
    x(1:10)
    session$flushReact()
    expect_equal(range_val(), c(1, 10))
    expect_equal(output$mean, "5.5")
    
    x(10:20)
    session$flushReact()
    expect_equal(range_val(), c(10, 20))
    expect_equal(output$min, "10")
  }) 
})
#> Test passed 🌈