diff --git a/R/module_init_data.R b/R/module_init_data.R
index 8c09936a7..f2a39ce6e 100644
--- a/R/module_init_data.R
+++ b/R/module_init_data.R
@@ -126,11 +126,18 @@ srv_init_data <- function(id, data) {
   vapply(
     datanames,
     function(dataname, datasets) {
-      hash <- rlang::hash(data[[dataname]])
+      x <- data[[dataname]]
+
+      code <- if (is.function(x) && !is.primitive(x)) {
+        x <- deparse1(x)
+        bquote(rlang::hash(deparse1(.(as.name(dataname)))))
+      } else {
+        bquote(rlang::hash(.(as.name(dataname))))
+      }
       sprintf(
         "stopifnot(%s == %s) # @linksto %s",
-        deparse1(bquote(rlang::hash(.(as.name(dataname))))),
-        deparse1(hash),
+        deparse1(code),
+        deparse1(rlang::hash(x)),
         dataname
       )
     },
diff --git a/tests/testthat/test-module_teal.R b/tests/testthat/test-module_teal.R
index b8878e566..ed01caaef 100644
--- a/tests/testthat/test-module_teal.R
+++ b/tests/testthat/test-module_teal.R
@@ -70,6 +70,8 @@ testthat::describe("srv_teal lockfile", {
     "creation process is invoked for teal.lockfile.mode = \"enabled\" ",
     "and snapshot is copied to teal_app.lock and removed after session ended"
   ), {
+    testthat::skip_if_not_installed("mirai")
+    testthat::skip_if_not_installed("renv")
     withr::with_options(
       list(teal.lockfile.mode = "enabled"),
       {
@@ -95,6 +97,8 @@ testthat::describe("srv_teal lockfile", {
     )
   })
   testthat::it("creation process is not invoked for teal.lockfile.mode = \"disabled\"", {
+    testthat::skip_if_not_installed("mirai")
+    testthat::skip_if_not_installed("renv")
     withr::with_options(
       list(teal.lockfile.mode = "disabled"),
       {
@@ -2280,44 +2284,127 @@ testthat::describe("Datanames with special symbols", {
   })
 
   testthat::it("(when used as non-native pipe) are present in datanames in the pre-processing code", {
-    testthat::expect_warning(
-      shiny::testServer(
-        app = srv_teal,
-        args = list(
-          id = "test",
-          data = within(
-            teal.data::teal_data(),
-            {
-              iris <- iris
-              mtcars <- mtcars
-              `%cbind%` <- function(lhs, rhs) cbind(lhs, rhs)
-              iris <- iris %cbind% data.frame("new_column")
-            }
-          ),
-          modules = modules(
-            module("module_1", server = function(id, data) data, , datanames = c("iris"))
-          ),
-          filter = teal_slices(
-            module_specific = TRUE
-          )
+    shiny::testServer(
+      app = srv_teal,
+      args = list(
+        id = "test",
+        data = within(
+          teal.data::teal_data(),
+          {
+            iris <- iris
+            mtcars <- mtcars
+            `%cbind%` <- function(lhs, rhs) cbind(lhs, rhs)
+            iris <- iris %cbind% data.frame("new_column")
+          }
         ),
-        expr = {
-          session$setInputs("teal_modules-active_tab" = "module_1")
-          session$flushReact()
+        modules = modules(
+          module("module_1", server = function(id, data) data, , datanames = c("iris"))
+        ),
+        filter = teal_slices(
+          module_specific = TRUE
+        )
+      ),
+      expr = {
+        session$setInputs("teal_modules-active_tab" = "module_1")
+        session$flushReact()
 
-          testthat::expect_contains(
-            strsplit(
-              x = teal.code::get_code(modules_output$module_1()()),
-              split = "\n"
-            )[[1]],
-            c(
-              "`%cbind%` <- function(lhs, rhs) cbind(lhs, rhs)",
-              ".raw_data <- list2env(list(iris = iris))"
+        testthat::expect_contains(
+          strsplit(
+            x = teal.code::get_code(modules_output$module_1()()),
+            split = "\n"
+          )[[1]],
+          c(
+            "`%cbind%` <- function(lhs, rhs) cbind(lhs, rhs)",
+            ".raw_data <- list2env(list(iris = iris))"
+          )
+        )
+      }
+    )
+  })
+})
+
+testthat::describe("teal.data code with a function defined", {
+  testthat::it("is fully reproducible", {
+    shiny::testServer(
+      app = srv_teal,
+      args = list(
+        id = "test",
+        data = reactive(within(teal.data::teal_data(), {
+          fun <- function(x) {
+            y <- x + 1
+            y + 3
+          }
+        })),
+        modules = modules(module("module_1", server = function(id, data) data))
+      ), ,
+      expr = {
+        session$setInputs("teal_modules-active_tab" = "module_1")
+        session$flushReact()
+
+        # Need to evaluate characters to preserve indentation
+        local_env <- new.env(parent = .GlobalEnv)
+        dat <- modules_output$module_1()()
+
+        eval(
+          parse(text = teal.code::get_code(dat)),
+          envir = local_env
+        )
+
+        testthat::expect_identical(local_env$fun(1), 5)
+        testthat::expect_identical(local_env$fun(1), dat[["fun"]](1))
+      }
+    )
+  })
+
+  testthat::it("has the correct code (with hash)", {
+    shiny::testServer(
+      app = srv_teal,
+      args = list(
+        id = "test",
+        data = reactive(within(teal.data::teal_data(), {
+          fun <- function(x) {
+            y <- x + 1
+            y + 3
+          }
+        })),
+        modules = modules(module("module_1", server = function(id, data) data))
+      ), ,
+      expr = {
+        session$setInputs("teal_modules-active_tab" = "module_1")
+        session$flushReact()
+
+        # Need to evaluate characters to preserve indentation
+        local_env <- new.env(parent = .GlobalEnv)
+        eval(
+          parse(
+            text = paste(
+              sep = "\n",
+              "fun <- function(x) {",
+              "    y <- x + 1",
+              "    y + 3",
+              "}"
             )
+          ),
+          envir = local_env
+        )
+        local(hash <- rlang::hash(deparse1(fun)), envir = local_env)
+
+        testthat::expect_setequal(
+          trimws(strsplit(
+            x = teal.code::get_code(modules_output$module_1()()),
+            split = "\n"
+          )[[1]]),
+          c(
+            "fun <- function(x) {",
+            "y <- x + 1",
+            "y + 3",
+            "}",
+            sprintf("stopifnot(rlang::hash(deparse1(fun)) == \"%s\")", local_env$hash),
+            ".raw_data <- list2env(list(fun = fun))",
+            "lockEnvironment(.raw_data)"
           )
-        }
-      ),
-      "'package:teal' may not be available when loading"
+        )
+      }
     )
   })
 })
diff --git a/tests/testthat/test-utils.R b/tests/testthat/test-utils.R
index 4904c4646..41c06581b 100644
--- a/tests/testthat/test-utils.R
+++ b/tests/testthat/test-utils.R
@@ -1,4 +1,5 @@
 testthat::test_that("get_teal_bs_theme", {
+  testthat::skip_if_not_installed("bslib")
   testthat::expect_true(is.null(get_teal_bs_theme()))
   withr::with_options(list("teal.bs_theme" = bslib::bs_theme(version = "5")), {
     testthat::expect_s3_class(get_teal_bs_theme(), "bs_theme")