[PATCH v5 2/3] oelib: add unit tests for kernel module detection helpers

[Sam Kent <sam.john.kent@gmail.com>]

Add tests for the filename pre-filter logic, is_kernel_module(), and
is_kernel_module_signed() to meta/lib/oeqa/selftest/cases/oelib/

Signed-off-by: Sam Kent <sam.john.kent@gmail.com>
---
 meta/lib/oeqa/selftest/cases/oelib/package.py | 108 ++++++++++++++++++
 1 file changed, 108 insertions(+)
 create mode 100644 meta/lib/oeqa/selftest/cases/oelib/package.py

diff --git a/meta/lib/oeqa/selftest/cases/oelib/package.py b/meta/lib/oeqa/selftest/cases/oelib/package.py
new file mode 100644
index 0000000..5751057
--- /dev/null
+++ b/meta/lib/oeqa/selftest/cases/oelib/package.py
@@ -0,0 +1,108 @@
+#
+# Copyright OpenEmbedded Contributors
+#
+# SPDX-License-Identifier: MIT
+#
+
+import mmap
+import os
+import tempfile
+from unittest.case import TestCase
+
+
+class TestKernelModuleFilenameFilter(TestCase):
+    """
+    The pre-filter in process_split_and_strip_files() selects candidates to
+    pass to is_elf(). It must use f.endswith(".ko"), not ".ko" in f, to avoid
+    false-positives on compressed modules (.ko.xz, .ko.gz).
+    """
+
+    ko_files = [
+        "driver.ko",
+        "net/foo.ko",
+    ]
+
+    not_ko_files = [
+        "driver.ko.xz",
+        "driver.ko.gz",
+        "driver.ko2",
+        "myko.c",
+        "vmlinux",
+    ]
+
+    def test_endswith_matches_ko(self):
+        for f in self.ko_files:
+            with self.subTest(f=f):
+                self.assertTrue(f.endswith(".ko"))
+
+    def test_endswith_rejects_non_ko(self):
+        for f in self.not_ko_files:
+            with self.subTest(f=f):
+                self.assertFalse(f.endswith(".ko"))
+
+    def test_old_predicate_had_false_positives(self):
+        # The previous check (".ko" in f) matched compressed modules — this is
+        # the regression the fix addresses.
+        false_positives = [f for f in self.not_ko_files if ".ko" in f]
+        self.assertEqual(false_positives, ["driver.ko.xz", "driver.ko.gz", "driver.ko2"])
+
+
+class TestIsKernelModule(TestCase):
+    """
+    is_kernel_module() detects kernel modules by searching for the
+    "vermagic=" string, which is always present in genuine .ko files.
+    """
+
+    def setUp(self):
+        from oe.package import is_kernel_module
+        self.is_kernel_module = is_kernel_module
+        self._tmpfile = None
+
+    def tearDown(self):
+        if self._tmpfile and os.path.exists(self._tmpfile):
+            os.unlink(self._tmpfile)
+
+    def _make_tmp(self, content):
+        f = tempfile.NamedTemporaryFile(delete=False, suffix=".ko")
+        f.write(content)
+        f.close()
+        return f.name
+
+    def test_detects_vermagic(self):
+        self._tmpfile = self._make_tmp(b"\x7fELF\x00" * 10 + b"vermagic=5.15.0" + b"\x00" * 10)
+        self.assertTrue(self.is_kernel_module(self._tmpfile))
+
+    def test_rejects_plain_elf(self):
+        self._tmpfile = self._make_tmp(b"\x7fELF\x00" * 50)
+        self.assertFalse(self.is_kernel_module(self._tmpfile))
+
+
+class TestIsKernelModuleSigned(TestCase):
+    """
+    is_kernel_module_signed() detects the "Module signature appended" tail
+    that the kernel's modsign infrastructure writes.
+    """
+
+    def setUp(self):
+        from oe.package import is_kernel_module_signed
+        self.is_kernel_module_signed = is_kernel_module_signed
+        self._tmpfile = None
+
+    def tearDown(self):
+        if self._tmpfile and os.path.exists(self._tmpfile):
+            os.unlink(self._tmpfile)
+
+    def _make_tmp(self, content):
+        f = tempfile.NamedTemporaryFile(delete=False, suffix=".ko")
+        f.write(content)
+        f.close()
+        return f.name
+
+    def test_detects_signed(self):
+        tail = b"Module signature appended\n\x00\x00"
+        self._tmpfile = self._make_tmp(b"\x00" * 64 + tail)
+        self.assertTrue(self.is_kernel_module_signed(self._tmpfile))
+
+    def test_rejects_unsigned(self):
+        self._tmpfile = self._make_tmp(b"\x7fELF\x00" * 20)
+        self.assertFalse(self.is_kernel_module_signed(self._tmpfile))
-- 
2.34.1