tests/testthat/test_get_closest.R

In UBC-MDS/distrrr: Calculate Distance Metrics Between Vectors

context("Test get_closest")
#'
#' This script tests the get_closest function of the distrrr package.
#'
#' The get_closest function returns indices of the top k rows in a dataframe that
#' are closest to a given observation based on a specified distance metric.
#'
#'

# Sample input
x <- c(1,1)
df <- data.frame(x=c(1, 1), y=c(1,2))
k <- 2

### Test Output
test_that("Output should be a vector containing numbers", {
  expect_true(class(get_closest(x, df, k))=="numeric")
})


test_that("Output should have a length of k",{
  if (length(df) >= k){
    expect_equal(length(get_closest(x, df, k)), k)
  }
  else {
    expect_equal(length(get_closest(x, df, k)), length(df))
  }
})

test_that("All numbers in output vector should be non-negative",{
  output <- get_closest(x, df, k)
  expect_true(all(output>=0))
})

### Test Input
test_that("Input data parameter should be a dataframe",{
  expect_error(get_closest(x, 8, k))
})

test_that("Input parameter top_k should be a number",{
  expect_error(get_closest(x, df, "two"))
})

test_that("Input parameter top_k should be a non-negative integer",{
  expect_error(get_closest(x, df, -2))
})

test_that("Message/warning appears if input parameter top_k is larger than size of data frame",{
  expect_message(get_closest(x, df, 100))
})

test_that("Input parameter point should be a vector of numerics",{
  expect_error(get_closest(c("7"), df, k))
})

test_that("Input parameter metric should be a character",{
  expect_error(get_closest(7, df, k, 100))
})

test_that("Input parameter metric should be a supported distance metric",{
  expect_error(get_closest(7, df, k, "mahalanobis"))
})