tests/testthat/test_predict.R

In UBC-MDS/ssgkmeansr: An R package for k-means clustering

context("Testing predict function")

# Generate test data frame
set.seed(46)
var <- .15
feature_one <- c(rnorm(5,-1, var),rnorm(5,0, var),rnorm(5,1, var))
feature_two <- c(rnorm(5,-1, var),rnorm(5,0, var),rnorm(5,1, var))

data_good <- data.frame(x1 = feature_one,
                        x2 = feature_two)

# Bad input - data frame with stings
data_bad_string<-data_good
data_bad_string[1,1]<-"susan"
data_bad_string[2,1]<-"GC"
data_bad_string[3,2] <-"sophia"

# Bad input - data frame with wrong dimentions
data_bad_1d<-data_good[,2]

# Bad input - empty data frame
data_bad_empty <- data.frame()

test_that("Predicting results match expectations", {
  
  n <-nrow(data_good)
  centroids <- as.data.frame(rbind(c(0,0),c(1,1),c(-1,-1)),row.names = NULL)

  output <- predict(data_good, centroids)
  
  # expected outputs:
  expect_equal(nrow(output), n) 
  expect_equal(max(output[,3])<4, TRUE)
  expect_equal(is.data.frame(output), TRUE)
  
  
})

test_that('Error in input data', {
  # expected error:
  expect_error(predict(data_bad_string), 'Input data must be numeric')
  expect_error(predict(data_bad_1d), 'Input data must have 2 columns')
  expect_error(predict(data_bad_empty), 'Input data cannot be empty')
})