Testing shiny application

[vinayprakash808]

Hi all, I refering the link Shiny - Server function testing with Shiny where I am testing the code in server functions. But i am getting error as shown below

app <- shinyApp(
  ui = fluidPage(
    numericInput("x", "X", value = 5),
    textOutput("txt")
  ),
  server = function(input, output, session) {
    myreactive <- reactive({
      input$x * 2
    })
    output$txt <- renderText({
      paste0("I am ", myreactive())
    })
  }
)


testServer(server, {
  session$setInputs(x = 1)
  expect_equal(myreactive(), 2)
})

Error

 shiny::runApp()
Loading required package: shiny
Warning in loadSupport(appDir, renv = sharedEnv, globalrenv = NULL) :
  Loading R/ subdirectory for Shiny application, but this directory appears to contain an R package. Sourcing files in R/ may cause unexpected behavior.
Error in isModuleServer(app) : object 'server' not found

Can anyone help me here

[nirgrahamuk]

There is an error in the documentation you are learning from
change

testServer(server, {
  session$setInputs(x = 1)
  expect_equal(myreactive(), 2)
})

to

testServer(app, {
  session$setInputs(x = 1)
  expect_equal(myreactive(), 2)
})

[vinayprakash808]

Thanks. But i tried your input. I get below error

[nirgrahamuk]

@vinayprakash808

app <- shinyApp(
  ui = fluidPage(
    numericInput("x", "X", value = 5),
    textOutput("txt")
  ),
  server = function(input, output, session) {
    myreactive <- reactive({
      input$x * 2
    })
    output$txt <- renderText({
      paste0("I am ", myreactive())
    })
  }
)

You need an app before you test it, like this one

[vinayprakash808]

Sorry I already had an app before.I forgot to mention

[nirgrahamuk]

Its not clear that you ran the app script to create the app object in the environment so it would be present when you ran testServer. If you didnt then you should, if you did, then im at my limit and cant help

[vinayprakash808]

Thanks.

Can anyone help me here? I Ran app.R file and the application for generated. However i am getting this error

[kraggle]

Hello,

I am also receiving the same error. However, I am testing a Shiny server module.

I made the Shiny app file structure as follows:

myapp/
|- app.R
|- R
|   |- module.R
`- tests
    `- testthat
        |- test-module.R

Where module.R contains the moduleUI and moduleServer code.

Then testServer tells me: Error in isModuleServer(app)`: object 'moduleServer' not found
Backtrace:

1. shiny::testServer(...)
2. shiny:::isModuleServer(app)`

I think something is wrong with my file structure but I cannot be certain. I followed the instructions how Hadley says in Chapter 21 of Mastering Shiny. We can also usethis::use_test() in our module to generate the file needed that has the tests.

Chapter 21 Testing | Mastering Shiny

-Cheers , Kraggle

[kraggle]

I found that for the test to work, we must Source our module code.

There should be a Source button on the RStudio UI. After sourcing the module (in your case the app.R), the test ran successfully.

Good luck!