diff --git a/run-vmtest/merge_test_lists.py b/run-vmtest/merge_test_lists.py
deleted file mode 100755
index 7505187..0000000
--- a/run-vmtest/merge_test_lists.py
+++ /dev/null
@@ -1,41 +0,0 @@
-#!/usr/bin/python3
-
-import sys
-
-def clean_line(line: str) -> str:
-    line = line.split('#')[0] # remove comment
-    line = line.strip()       # strip whitespace
-    return line
-
-def read_clean_and_sort_input() -> list[str]:
-    input = []
-    for line in sys.stdin:
-        line = clean_line(line)
-        if len(line) == 0:
-            continue
-        input.append(line)
-    input.sort()
-    return input
-
-def dedup_subtests(lines: list[str]):
-    i = 0
-    j = 1
-    while j < len(lines):
-        l1 = lines[i]
-        l2 = lines[j]
-        # for a pair of "foo_test" and "foo_test/subtest"
-        # remove a subtest from the list
-        if l1 == l2 or ('/' not in l1) and ('/' in l2) and l2.startswith(l1):
-            # print(f"removing '{l2}' because '{l1}' is in the list")
-            lines.remove(l2)
-        else:
-            i += 1
-            j += 1
-
-if __name__ == '__main__':
-    lines = read_clean_and_sort_input()
-    dedup_subtests(lines)
-    for line in lines:
-        print(line)
-
-
diff --git a/run-vmtest/normalize_bpf_test_names.py b/run-vmtest/normalize_bpf_test_names.py
new file mode 100755
index 0000000..b8a8828
--- /dev/null
+++ b/run-vmtest/normalize_bpf_test_names.py
@@ -0,0 +1,70 @@
+#!/usr/bin/python3
+
+# This script normalizes a list of selftests/bpf test names. These
+# lists have the following format:
+#    * each line indicates a test name
+#    * a line can contain an end-line comment, starting with #
+#
+# The test names may contain spaces, commas, and potentially other characters.
+#
+# The purpose of this script is to take in a composite allow/denylist
+# (usually produced as an append of multiple different lists) and
+# transform it into one clean deduplicated list.
+#
+# In addition to dedup of tests by exact match, subtests are taken
+# into account. For example, one source denylist may contain a test
+# "a_test/subtest2", and another may contain simply "a_test". In such
+# case "a_test" indicates that no subtest of "a_test" should run, and
+# so "a_test/subtest2" shouldn't be in the list.
+#
+# The result is printed to stdout
+
+import sys
+
+def clean_line(line: str) -> str:
+    line = line.split('#')[0] # remove comment
+    line = line.strip()       # strip whitespace
+    return line
+
+def read_clean_and_sort_input(file) -> list[str]:
+    input = []
+    for line in file:
+        line = clean_line(line)
+        if len(line) == 0:
+            continue
+        input.append(line)
+    input.sort()
+    return input
+
+# Deduplicate subtests and yield the next unique test name
+def next_test(lines: list[str]):
+
+    if not lines:
+        return
+
+    prev = lines[0]
+
+    def is_subtest(line: str) -> bool:
+        return ('/' in line) and ('/' not in prev) and line.startswith(prev)
+
+    yield lines[0]
+    for line in lines[1:]:
+        if prev == line or is_subtest(line):
+            continue
+        yield line
+        prev = line
+
+
+if __name__ == '__main__':
+
+    if len(sys.argv) != 2:
+        print("Usage: merge_test_lists.py <filename>", file=sys.stderr)
+        sys.exit(1)
+
+    lines = []
+    with open(sys.argv[1]) as file:
+        lines = read_clean_and_sort_input(file)
+
+    for line in next_test(lines):
+        print(line)
+
diff --git a/run-vmtest/prepare-bpf-selftests.sh b/run-vmtest/prepare-bpf-selftests.sh
index ed027eb..89ae79a 100755
--- a/run-vmtest/prepare-bpf-selftests.sh
+++ b/run-vmtest/prepare-bpf-selftests.sh
@@ -6,18 +6,20 @@ function merge_test_lists_into() {
     local out="$1"
     shift
     local files=("$@")
-    echo -n > "$out"
 
-    # first, append all the input lists into one
+    local list=$(mktemp)
+    echo -n > "$list"
+    # append all the source lists into one
     for file in "${files[@]}"; do
         if [[ -f "$file" ]]; then
-            echo "cat $file >> $out"
-            cat "$file" >> "$out"
+            echo "Include $file"
+            cat "$file" >> "$list"
         fi
     done
 
-    # then merge the list of test names
-    cat "$out" | python3 "$(dirname $0)/merge_test_lists.py" > "$out"
+    # then normalize the list of test names
+    $GITHUB_ACTION_PATH/normalize_bpf_test_names.py "$list" > "$out"
+    rm "$list"
 }
 
 # Read arrays from pipe-separated strings
diff --git a/run-vmtest/tests/merge_test_lists/expected-output.txt b/run-vmtest/tests/normalize_bpf_test_names/expected-output.txt
similarity index 100%
rename from run-vmtest/tests/merge_test_lists/expected-output.txt
rename to run-vmtest/tests/normalize_bpf_test_names/expected-output.txt
diff --git a/run-vmtest/tests/merge_test_lists/input.txt b/run-vmtest/tests/normalize_bpf_test_names/input.txt
similarity index 100%
rename from run-vmtest/tests/merge_test_lists/input.txt
rename to run-vmtest/tests/normalize_bpf_test_names/input.txt
diff --git a/run-vmtest/tests/merge_test_lists/run-test.sh b/run-vmtest/tests/normalize_bpf_test_names/run-test.sh
similarity index 62%
rename from run-vmtest/tests/merge_test_lists/run-test.sh
rename to run-vmtest/tests/normalize_bpf_test_names/run-test.sh
index 84aa342..fd52d35 100755
--- a/run-vmtest/tests/merge_test_lists/run-test.sh
+++ b/run-vmtest/tests/normalize_bpf_test_names/run-test.sh
@@ -5,6 +5,6 @@ set -euo pipefail
 GITHUB_ACTION_PATH=$(realpath ../..)
 
 rm -f output.txt
-cat input.txt | $GITHUB_ACTION_PATH/merge_test_lists.py 2>&1 > output.txt
+$GITHUB_ACTION_PATH/normalize_bpf_test_names.py input.txt 2>&1 > output.txt
 diff expected-output.txt output.txt