u-boot/tools/binman/elf_test.py
Simon Glass b2b0df8f39 binman: Add comments to elf_test
The purpose of some of the tests is not obvious from the function names.
Add a few comments to help with understanding.

Signed-off-by: Simon Glass <sjg@chromium.org>
2018-08-01 16:30:07 -06:00

136 lines
4.7 KiB
Python

# SPDX-License-Identifier: GPL-2.0+
# Copyright (c) 2017 Google, Inc
# Written by Simon Glass <sjg@chromium.org>
#
# Test for the elf module
import os
import sys
import unittest
import elf
import test_util
binman_dir = os.path.dirname(os.path.realpath(sys.argv[0]))
class FakeEntry:
"""A fake Entry object, usedfor testing
This supports an entry with a given size.
"""
def __init__(self, contents_size):
self.contents_size = contents_size
self.data = 'a' * contents_size
def GetPath(self):
return 'entry_path'
class FakeSection:
"""A fake Section object, used for testing
This has the minimum feature set needed to support testing elf functions.
A LookupSymbol() function is provided which returns a fake value for amu
symbol requested.
"""
def __init__(self, sym_value=1):
self.sym_value = sym_value
def GetPath(self):
return 'section_path'
def LookupSymbol(self, name, weak, msg):
"""Fake implementation which returns the same value for all symbols"""
return self.sym_value
class TestElf(unittest.TestCase):
def testAllSymbols(self):
"""Test that we can obtain a symbol from the ELF file"""
fname = os.path.join(binman_dir, 'test', 'u_boot_ucode_ptr')
syms = elf.GetSymbols(fname, [])
self.assertIn('.ucode', syms)
def testRegexSymbols(self):
"""Test that we can obtain from the ELF file by regular expression"""
fname = os.path.join(binman_dir, 'test', 'u_boot_ucode_ptr')
syms = elf.GetSymbols(fname, ['ucode'])
self.assertIn('.ucode', syms)
syms = elf.GetSymbols(fname, ['missing'])
self.assertNotIn('.ucode', syms)
syms = elf.GetSymbols(fname, ['missing', 'ucode'])
self.assertIn('.ucode', syms)
def testMissingFile(self):
"""Test that a missing file is detected"""
entry = FakeEntry(10)
section = FakeSection()
with self.assertRaises(ValueError) as e:
syms = elf.LookupAndWriteSymbols('missing-file', entry, section)
self.assertIn("Filename 'missing-file' not found in input path",
str(e.exception))
def testOutsideFile(self):
"""Test a symbol which extends outside the entry area is detected"""
entry = FakeEntry(10)
section = FakeSection()
elf_fname = os.path.join(binman_dir, 'test', 'u_boot_binman_syms')
with self.assertRaises(ValueError) as e:
syms = elf.LookupAndWriteSymbols(elf_fname, entry, section)
self.assertIn('entry_path has offset 4 (size 8) but the contents size '
'is a', str(e.exception))
def testMissingImageStart(self):
"""Test that we detect a missing __image_copy_start symbol
This is needed to mark the start of the image. Without it we cannot
locate the offset of a binman symbol within the image.
"""
entry = FakeEntry(10)
section = FakeSection()
elf_fname = os.path.join(binman_dir, 'test', 'u_boot_binman_syms_bad')
self.assertEqual(elf.LookupAndWriteSymbols(elf_fname, entry, section),
None)
def testBadSymbolSize(self):
"""Test that an attempt to use an 8-bit symbol are detected
Only 32 and 64 bits are supported, since we need to store an offset
into the image.
"""
entry = FakeEntry(10)
section = FakeSection()
elf_fname = os.path.join(binman_dir, 'test', 'u_boot_binman_syms_size')
with self.assertRaises(ValueError) as e:
syms = elf.LookupAndWriteSymbols(elf_fname, entry, section)
self.assertIn('has size 1: only 4 and 8 are supported',
str(e.exception))
def testNoValue(self):
"""Test the case where we have no value for the symbol
This should produce -1 values for all thress symbols, taking up the
first 16 bytes of the image.
"""
entry = FakeEntry(20)
section = FakeSection(sym_value=None)
elf_fname = os.path.join(binman_dir, 'test', 'u_boot_binman_syms')
syms = elf.LookupAndWriteSymbols(elf_fname, entry, section)
self.assertEqual(chr(255) * 16 + 'a' * 4, entry.data)
def testDebug(self):
"""Check that enabling debug in the elf module produced debug output"""
elf.debug = True
entry = FakeEntry(20)
section = FakeSection()
elf_fname = os.path.join(binman_dir, 'test', 'u_boot_binman_syms')
with test_util.capture_sys_output() as (stdout, stderr):
syms = elf.LookupAndWriteSymbols(elf_fname, entry, section)
elf.debug = False
self.assertTrue(len(stdout.getvalue()) > 0)
if __name__ == '__main__':
unittest.main()