Add DTx function, check and testHEADmain

The tolerance of one test had to be increased in test_deSolve.R,
and four vdiffr snapshots with negligible differences were updated.

Tests run with a maximum of 16 cores when running in the Agroscope
Apptainer environment.

1 files changed, 49 insertions, 0 deletions

diff --git a/tests/testthat/test_endpoints.R b/tests/testthat/test_endpoints.R
new file mode 100644
index 00000000..284e1379
--- /dev/null
+++ b/tests/testthat/test_endpoints.R
@@ -0,0 +1,49 @@
+context("DTx calculations")
+
+test_that("The DTx function gives the same results as the endpoints function", {
+  # We silently assume that the calculations in the endpoint function are correct
+
+  SFO_fit <- fits[["SFO", "FOCUS_C"]]
+  SFO_distimes <- endpoints(SFO_fit)$distimes
+  SFO_DTx <- DTx("SFO", c(k = parms(SFO_fit)[["k_parent"]]))
+
+  expect_equal(
+    as.numeric(SFO_distimes),
+    as.numeric(SFO_DTx)
+  )
+
+  FOMC_fit <- fits[["FOMC", "FOCUS_C"]]
+  FOMC_distimes <- endpoints(FOMC_fit)$distimes
+  FOMC_DTx <- DTx("FOMC", c(
+      alpha = parms(FOMC_fit)[["alpha"]],
+      beta = parms(FOMC_fit)[["beta"]]), exact = TRUE)
+
+  expect_equal(
+    as.numeric(FOMC_distimes),
+    as.numeric(FOMC_DTx)
+  )
+
+  DFOP_fit <- fits[["DFOP", "FOCUS_C"]]
+  DFOP_distimes <- endpoints(DFOP_fit)$distimes
+  DFOP_DTx <- DTx("DFOP", c(
+      k1 = parms(DFOP_fit)[["k1"]],
+      k2 = parms(DFOP_fit)[["k2"]],
+      g = parms(DFOP_fit)[["g"]]), exact = TRUE)
+
+  expect_equal(
+    as.numeric(DFOP_distimes),
+    as.numeric(DFOP_DTx)
+  )
+
+  HS_fit <- fits[["HS", "FOCUS_C"]]
+  HS_distimes <- endpoints(HS_fit)$distimes
+  HS_DTx <- DTx("HS", c(
+      k1 = parms(HS_fit)[["k1"]],
+      k2 = parms(HS_fit)[["k2"]],
+      tb = parms(HS_fit)[["tb"]]), exact = TRUE)
+
+  expect_equal(
+    as.numeric(HS_distimes),
+    as.numeric(HS_DTx)
+  )
+})