R Shiny - Subset dataframe based on reactive input

I am building a shiny app and I need to subset a dataframe based on a user input. I have tried many different ways to do this but I keep running into errors. Currently, this seems to be the simplest method but I get the following error:

Warning in is.na(e2) : is.na() applied to non-(list or vector) of type 'closure'
Error in ==.default(test$MARKET, var) : comparison (1) is possible only for atomic and list types

I am pretty stuck. Does anyone have some guidance for me? Thanks!

library(shiny)
shinyServer(function(input, output) {
      var <- reactive({input$var})
      subsetTest <- subset(test, test$MARKET==var)
      y <- subsetTest()$PRICE
      x <- subsetTest()$DATE
  output$ngplot <- renderPlot({
    print(ggplot(data=subsetTest(), aes(x=y, y=x)) + geom_line())
  })
})