diff --git a/tests/testthat/test-poped.R b/tests/testthat/test-poped.R
index ce53ad11..c8f4bc62 100644
--- a/tests/testthat/test-poped.R
+++ b/tests/testthat/test-poped.R
@@ -316,6 +316,62 @@ if (requireNamespace("PopED", quietly=TRUE)) {
 
   })
 
+  test_that("shrinkage", {
+
+    f <- function() {
+      ini({
+        tV <- 72.8
+        tKa <- 0.25
+        tCl <- 3.75
+        tF <- fix(0.9)
+
+        eta.v ~ 0.09
+        eta.ka ~ 0.09
+        eta.cl ~0.25^2
+
+        prop.sd <- fix(sqrt(0.04))
+        add.sd <- fix(sqrt(5e-6))
+
+      })
+      model({
+        V<-tV*exp(eta.v)
+        KA<-tKa*exp(eta.ka)
+        CL<-tCl*exp(eta.cl)
+        Favail <- tF
+        N <-  floor(time/TAU)+1
+        y <- (DOSE*Favail/V)*(KA/(KA - CL/V)) *
+          (exp(-CL/V * (time - (N - 1) * TAU)) *
+             (1 - exp(-N * CL/V * TAU))/(1 - exp(-CL/V * TAU)) -
+             exp(-KA * (time - (N - 1) * TAU)) * (1 - exp(-N * KA * TAU))/(1 - exp(-KA * TAU)))
+
+        y ~ prop(prop.sd) + add(add.sd)
+      })
+    }
+
+    # minxt, maxxt
+    e <- et(list(c(0, 10),
+                 c(0, 10),
+                 c(0, 10),
+                 c(240, 248),
+                 c(240, 248))) %>%
+      as.data.frame()
+
+    #xt
+    e$time <-  c(1,2,8,240,245)
+
+
+    babel.db <- nlmixr2(f, e, "poped",
+                        popedControl(groupsize=20,
+                                     bUseGrouped_xt=TRUE,
+                                     a=list(c(DOSE=20,TAU=24),
+                                            c(DOSE=40, TAU=24)),
+                                     maxa=c(DOSE=200,TAU=24),
+                                     mina=c(DOSE=0,TAU=24)))
+
+    expect_error(shrinkage(babel.db), NA)
+
+  })
+
   ##  The tests run interactively runs OK
   ## However, the capture output seems to be interfere with the tests (from PopED)
   # So... these are commented out for now.