--- a
+++ b/tests/testthat/test-recruit.R
@@ -0,0 +1,60 @@
+### Testing accrual() constructor
+
+acc_obj <- accrual(
+  treatment_arm_ids = list(T1 = as.integer(1), T2 = as.integer(2)),
+  shared_control = TRUE,
+  centres_df = data.frame(
+    site = 1:2,
+    start_month = c(1, 5),
+    mean_rate = c(10, 18),
+    region = c(1, 1),
+    site_cap = c(40, 20),
+    start_week = c(1, 20)
+  ),
+  accrual_period = as.integer(36)
+)
+
+test_that(paste(
+  "Constructor for accrual produces an object of classes",
+  "S7_object and biomkrAccrual::accrual"
+), {
+  checkmate::expect_class(acc_obj, c(
+    "biomkrAccrual::accrual",
+    "S7_object"
+  ))
+})
+
+
+### Testing is.accrual()
+
+test_that(paste(
+  "Constructor for accrual produces an object of classes",
+  "S7_object and biomkrAccrual::accrual"
+), {
+  checkmate::expect_class(acc_obj, c(
+    "biomkrAccrual::accrual",
+    "S7_object"
+  ))
+})
+
+
+### Testing treat_sums()
+arr <- array(1:24, 2:4)
+
+test_that("Can sum by treatment a 3-D accrual array", {
+  checkmate::expect_integer(
+    treat_sums(arr),
+    min.len = 1,
+    max.len = ncol(arr),
+    lower = 0,
+    any.missing = FALSE,
+    null.ok = FALSE
+  )
+})
+
+test_that("Output correct from treat_sums for valid input", {
+  expect_identical(
+    treat_sums(arr),
+    as.integer(c(84, 100, 116))
+  )
+})
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