Add CTM topicmodels method to train function

[jandziak]

test_that("Test topicmodels for many models", {
k <- 30
SEED <- 2016
x <- tmCorpus(lapply(1:100, function(x) paste(sample(LETTERS, 11),
collapse = "")))
y <- DocumentTermMatrix(x)
rownames(y) <- meta(x, "title")
jss_TM <-
list(VEM = train(y, k = k, control = list(seed = SEED)),
VEM_fixed = train(y, k = k,
control = list(estimate.alpha = FALSE, seed = SEED)),
Gibbs = train(y, k = k, method = "Gibbs",
control = list(seed = SEED, burnin = 1000,
thin = 100, iter = 1000)))
CTM = CTM(JSS_dtm, k = k,
control = list(seed = SEED,
var = list(tol = 10^-4),
em = list(tol = 10^-3))))
expect_equal(class(jss_TM$VEM), "tmTopicModel")
expect_equal(class(jss_TM$VEM_fixed), "tmTopicModel")
expect_equal(class(jss_TM$Gibbs), "tmTopicModel")
})