diff --git a/tests/testthat/_snaps/aaa-auto.md b/tests/testthat/_snaps/aaa-auto.md
index c37d623cd2b..083286d431d 100644
--- a/tests/testthat/_snaps/aaa-auto.md
+++ b/tests/testthat/_snaps/aaa-auto.md
@@ -5804,7 +5804,7 @@
       hrg_sample_impl(hrg = NULL)
     Condition
       Error in `hrg_sample_impl()`:
-      ! At <file>:<line> : Assertion failed: n >= 0. This is an unexpected igraph error; please report this as a bug, along with the steps to reproduce it.
+      ! At <file>:<line>: Assertion failed: n >= 0. This is an unexpected igraph error; please report this as a bug, along with the steps to reproduce it.
       Please restart your R session to avoid crashes or other surprising behavior.
 
 # hrg_sample_many_impl basic
@@ -5835,7 +5835,7 @@
       hrg_sample_many_impl(hrg = NULL, num_samples = 2)
     Condition
       Error in `hrg_sample_many_impl()`:
-      ! At <file>:<line> : Assertion failed: n >= 0. This is an unexpected igraph error; please report this as a bug, along with the steps to reproduce it.
+      ! At <file>:<line>: Assertion failed: n >= 0. This is an unexpected igraph error; please report this as a bug, along with the steps to reproduce it.
       Please restart your R session to avoid crashes or other surprising behavior.
 
 # hrg_game_impl basic
@@ -5857,7 +5857,7 @@
       hrg_game_impl(hrg = NULL)
     Condition
       Error in `hrg_game_impl()`:
-      ! At <file>:<line> : Assertion failed: n >= 0. This is an unexpected igraph error; please report this as a bug, along with the steps to reproduce it.
+      ! At <file>:<line>: Assertion failed: n >= 0. This is an unexpected igraph error; please report this as a bug, along with the steps to reproduce it.
       Please restart your R session to avoid crashes or other surprising behavior.
 
 # hrg_consensus_impl errors
@@ -11198,7 +11198,7 @@
     Condition
       Warning in `connect_neighborhood_impl()`:
       Order smaller than two, graph will be unchanged.
-      Source: operators/connect_neighborhood.c:85
+      Source: <file>:<line>
     Output
       IGRAPH U--- 5 5 -- Ring graph
       + attr: name (g/c), mutual (g/l), circular (g/l)
diff --git a/tests/testthat/_snaps/games.md b/tests/testthat/_snaps/games.md
index 15522aa0df9..8b30cb21907 100644
--- a/tests/testthat/_snaps/games.md
+++ b/tests/testthat/_snaps/games.md
@@ -5,7 +5,7 @@
     Condition
       Error in `sample_degseq()`:
       ! Cannot make a connected graph from the given degree sequence. Invalid value
-      Source: games/degree_sequence_vl/gengraph_mr-connected.cpp:<linenumber>
+      Source: <file>:<line>
 
 # sample_degseq() works -- Power-law degree error
 
@@ -14,5 +14,5 @@
     Condition
       Error in `sample_degseq()`:
       ! Cannot realize the given degree sequence as an undirected, simple graph. Invalid value
-      Source: games/degree_sequence_vl/gengraph_mr-connected.cpp:<linenumber>
+      Source: <file>:<line>
 
diff --git a/tests/testthat/helper.R b/tests/testthat/helper.R
index 91c6660ea60..7b3609ceb1e 100644
--- a/tests/testthat/helper.R
+++ b/tests/testthat/helper.R
@@ -44,21 +44,28 @@ expect_not_identical_graphs <- function(g1, g2, ...) {
   expect_false(identical_graphs(g1, g2, ...))
 }
 
+scrub_igraph_file_paths <- function(y) {
+  # Scrub file name and line number from error/warning messages
+  # Handles "Source: filename:linenumber" and "At path/to/file:line :" patterns
+  # The "At" pattern may have an optional space before the final colon
+  y <- gsub("Source: [^:]+:(\\d+|xx|<linenumber>)", "Source: <file>:<line>", y)
+  y <- gsub("At [^:]+:(\\d+|xx) ?:", "At <file>:<line>:", y)
+  y
+}
+
 expect_snapshot_igraph_error <- function(x, ...) {
   inject(expect_snapshot(
     {{ x }},
     error = TRUE,
-    transform = function(y) {
-      # Scrub file name and line number from error/warning messages
-      # Handles "Source: filename:linenumber" and "At path/to/file:line :" patterns
-      y <- gsub(
-        "Source: [^:]+:(\\d+|xx|<linenumber>)",
-        "Source: <file>:<line>",
-        y
-      )
-      y <- gsub("At [^:]+:(\\d+|xx) :", "At <file>:<line> :", y)
-      y
-    },
+    transform = scrub_igraph_file_paths,
+    ...
+  ))
+}
+
+expect_snapshot_igraph <- function(x, ...) {
+  inject(expect_snapshot(
+    {{ x }},
+    transform = scrub_igraph_file_paths,
     ...
   ))
 }
diff --git a/tests/testthat/test-aaa-auto.R b/tests/testthat/test-aaa-auto.R
index 50f55a7068a..2f060d488c7 100644
--- a/tests/testthat/test-aaa-auto.R
+++ b/tests/testthat/test-aaa-auto.R
@@ -6733,6 +6733,9 @@ test_that("hrg_sample_impl errors", {
   skip_if(Sys.getenv("R_SANITIZER") == "true")
   withr::local_seed(20250909)
   local_igraph_options(print.id = FALSE)
+  # FIXME: This test triggers an assertion failure in the C code when passing
+  # NULL/empty HRG. The C code should validate input and return a proper error
+  # message instead of an assertion failure.
   expect_snapshot_igraph_error(hrg_sample_impl(
     hrg = NULL
   ))
@@ -6763,6 +6766,9 @@ test_that("hrg_sample_many_impl errors", {
   skip_if(Sys.getenv("R_SANITIZER") == "true")
   withr::local_seed(20250909)
   local_igraph_options(print.id = FALSE)
+  # FIXME: This test triggers an assertion failure in the C code when passing
+  # NULL/empty HRG. The C code should validate input and return a proper error
+  # message instead of an assertion failure.
   expect_snapshot_igraph_error(hrg_sample_many_impl(
     hrg = NULL,
     num_samples = 2
@@ -6792,6 +6798,9 @@ test_that("hrg_game_impl errors", {
   skip_if(Sys.getenv("R_SANITIZER") == "true")
   withr::local_seed(20250909)
   local_igraph_options(print.id = FALSE)
+  # FIXME: This test triggers an assertion failure in the C code when passing
+  # NULL/empty HRG. The C code should validate input and return a proper error
+  # message instead of an assertion failure.
   expect_snapshot_igraph_error(hrg_game_impl(
     hrg = NULL
   ))
@@ -11044,7 +11053,7 @@ test_that("connect_neighborhood_impl basic", {
   withr::local_seed(20250909)
   local_igraph_options(print.id = FALSE)
   g <- make_ring(5)
-  expect_snapshot(connect_neighborhood_impl(
+  expect_snapshot_igraph(connect_neighborhood_impl(
     graph = g,
     order = 1,
     mode = c("all", "out", "in")
diff --git a/tests/testthat/test-games.R b/tests/testthat/test-games.R
index 0c786e1d23a..46b4c1e7bb5 100644
--- a/tests/testthat/test-games.R
+++ b/tests/testthat/test-games.R
@@ -71,13 +71,9 @@ test_that("sample_degseq() works -- exponential degree error", {
     replace = TRUE,
     prob = exp(-0.5 * (1:100))
   )
-  expect_snapshot(
-    {
-      sample_degseq(exponential_degrees, method = "vl")
-    },
-    error = TRUE,
-    transform = function(x) sub("\\:[0-9]+", ":<linenumber>", x)
-  )
+  expect_snapshot_igraph_error({
+    sample_degseq(exponential_degrees, method = "vl")
+  })
 })
 
 test_that("sample_degseq() works -- Power-law degree ok", {
@@ -91,13 +87,9 @@ test_that("sample_degseq() works -- Power-law degree error", {
   withr::local_seed(7)
   powerlaw_degrees <- sample(1:100, 100, replace = TRUE, prob = (1:100)^-2)
 
-  expect_snapshot(
-    {
-      sample_degseq(powerlaw_degrees, method = "vl")
-    },
-    error = TRUE,
-    transform = function(x) sub("\\:[0-9]+", ":<linenumber>", x)
-  )
+  expect_snapshot_igraph_error({
+    sample_degseq(powerlaw_degrees, method = "vl")
+  })
 })
 
 test_that("sample_degseq() works -- fast.heur.simple", {