test(seeds): add testthat + test that seeds ensure consistency between runs

Author: amyheather

DESCRIPTION

@@ -21,5 +21,7 @@ Imports:
     magrittr
 Suggests: 
     knitr,
-    rmarkdown
+    rmarkdown,
+    testthat (>= 3.0.0)
 VignetteBuilder: knitr
+Config/testthat/edition: 3

tests/testthat.R

@@ -0,0 +1,12 @@
+# This file is part of the standard setup for testthat.
+# It is recommended that you do not modify it.
+#
+# Where should you do additional test configuration?
+# Learn more about the roles of various files in:
+# * https://r-pkgs.org/testing-design.html#sec-tests-files-overview
+# * https://testthat.r-lib.org/articles/special-files.html
+
+library(testthat)
+library(simulation)
+
+test_check("simulation")

tests/testthat/test-model.R

@@ -0,0 +1,38 @@
+test_that("the same seed returns the same result", {
+
+  # Run model twice using same run number (which will set the seed)
+  env1 <- model(run_number=0, param=defaults())
+  env2 <- model(run_number=0, param=defaults())
+
+  # Compare output results
+  expect_identical(
+    env1 %>% get_mon_arrivals(),
+    env2 %>% get_mon_arrivals())
+  expect_identical(
+    env1 %>% get_mon_resources(),
+    env2 %>% get_mon_resources())
+
+  # Conversely, if run with different run number, expect different
+  env1 <- model(run_number=0, param=defaults())
+  env2 <- model(run_number=1, param=defaults())
+
+  # Compare output results
+  expect_failure(expect_identical(
+    env1 %>% get_mon_arrivals(),
+    env2 %>% get_mon_arrivals()))
+  expect_failure(expect_identical(
+    env1 %>% get_mon_resources(),
+    env2 %>% get_mon_resources()))
+
+  # Repeat experiment, but with multiple replications
+  envs1 <- trial(param=defaults())
+  envs2 <- trial(param=defaults())
+
+  # Aggregate results from replications in each trial, then compare full trial
+  expect_identical(
+    do.call(rbind, lapply(envs1, get_mon_arrivals)),
+    do.call(rbind, lapply(envs2, get_mon_arrivals)))
+  expect_identical(
+    do.call(rbind, lapply(envs1, get_mon_resources)),
+    do.call(rbind, lapply(envs2, get_mon_resources)))
+})