tests/testthat/test-Shapley.R

In iml: Interpretable Machine Learning

expected_colnames <- c("feature", "phi", "phi.var", "feature.value")

test_that("Shapley works for single output and single feature", {
  skip_on_os("windows")
  skip_on_cran()
  x.interest <- X[1, ]

  set.seed(42)
  shap <- Shapley$new(predictor1, x.interest, sample.size = 400)
  dat <- shap$results
  expect_false("data.table" %in% class(dat))
  expect_class(dat, "data.frame")
  expect_equal(colnames(dat), expected_colnames)
  expect_equal(nrow(dat), ncol(X))
  expect_equal(sum(dat$phi), unlist(f(x.interest) - mean(f(X)$pred), use.names = FALSE), tolerance = 0.02)
  p <- plot(shap)
  expect_s3_class(p, c("gg", "ggplot"))
  p

  x.interest2 <- X[2, ]
  shap$explain(x.interest2)
  dat <- shap$results
  expect_class(dat, "data.frame")
  expect_equal(colnames(dat), expected_colnames)
  expect_equal(nrow(dat), ncol(X))
  expect_equal(sum(dat$phi), unlist(f(x.interest2) - mean(f(X)$pred), use.names = FALSE), tolerance = 0.05)

  shap <- Shapley$new(predictor1, sample.size = 400)
  shap$explain(x.interest)
})

test_that("Shapley works for multiple output", {
  skip_on_os("windows")
  skip_on_cran()
  x.interest <- X[1, ]
  set.seed(42)
  shap <- Shapley$new(predictor2, x.interest, sample.size = 400)
  dat <- shap$results
  expect_class(dat, "data.frame")
  expect_equal(colnames(dat), c("feature", "class", "phi", "phi.var", "feature.value"))
  expect_equal(sum(dat$phi[dat$class == "pred"]), unlist(f(x.interest) - mean(f(X)$pred), use.names = FALSE), tolerance = 0.02)
  p <- plot(shap)
  expect_s3_class(p, c("gg", "ggplot"))
  p
})