test_that("joint entropies work", {
  data(lawdata)
  df.att <- lawdata[[4]]

  df.att.ed <- data.frame(
    status   = df.att$status,
    gender   = df.att$gender,
    office   = df.att$office-1,
    years    = ifelse(df.att$years<=3,0,
                      ifelse(df.att$years<=13,1,2)),
    age      = ifelse(df.att$age<=35,0,
                      ifelse(df.att$age<=45,1,2)),
    practice = df.att$practice,
    lawschool= df.att$lawschool-1)

  H.joint <- joint_entropy(df.att.ed)
  result <- c(status = 1, gender = 0.817, office = 1.125, years = 1.585,
              age = 1.585, practice = 0.983, lawschool = 1.533)
  expect_identical(diag(H.joint$matrix),result)
})