kunit: tool: refactor internal kconfig handling, allow overriding

Currently, you cannot ovewrwrite what's in your kunitconfig via
--kconfig_add.
Nor can you override something in a qemu_config via either means.

This patch makes it so we have this level of priority
* --kconfig_add
* kunitconfig file (the default or the one from --kunitconfig)
* qemu_config

The rationale for this order is that the more "dynamic" sources of
kconfig options should take priority.

--kconfig_add is obviously the most dynamic.
And for kunitconfig, users probably tweak the file manually or specify
--kunitconfig more often than they delve into qemu_config python files.

And internally, we convert the kconfigs from a python list into a set or
dict fairly often. We should just use a dict internally.
We exposed the set transform in the past since we didn't define __eq__,
so also take the chance to shore up the kunit_kconfig.Kconfig interface.

Example
=======

Let's consider the unrealistic example where someone would want to
disable CONFIG_KUNIT.
I.e. they run
$ ./tools/testing/kunit/kunit.py config --kconfig_add=CONFIG_KUNIT=n

Before
------
We'd write the following
> # CONFIG_KUNIT is not set
> CONFIG_KUNIT_ALL_TESTS=y
> CONFIG_KUNIT_TEST=y
> CONFIG_KUNIT=y
> CONFIG_KUNIT_EXAMPLE_TEST=y

And we'd error out with
> ERROR:root:Not all Kconfig options selected in kunitconfig were in the generated .config.
> This is probably due to unsatisfied dependencies.
> Missing: # CONFIG_KUNIT is not set

After
-----
We'd write the following
> # CONFIG_KUNIT is not set
> CONFIG_KUNIT_TEST=y
> CONFIG_KUNIT_ALL_TESTS=y
> CONFIG_KUNIT_EXAMPLE_TEST=y

And we'd error out with
> ERROR:root:Not all Kconfig options selected in kunitconfig were in the generated .config.
> This is probably due to unsatisfied dependencies.
> Missing: CONFIG_KUNIT_EXAMPLE_TEST=y, CONFIG_KUNIT_TEST=y, CONFIG_KUNIT_ALL_TESTS=y

Signed-off-by: Daniel Latypov <dlatypov@google.com>
Reviewed-by: David Gow <davidgow@google.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

1 files changed, 25 insertions, 20 deletions

diff --git a/tools/testing/kunit/kunit_config.py b/tools/testing/kunit/kunit_config.py
index 75a8dc1683d4..898b2a35eb29 100644
--- a/tools/testing/kunit/kunit_config.py
+++ b/tools/testing/kunit/kunit_config.py
@@ -8,7 +8,7 @@
 
 from dataclasses import dataclass
 import re
-from typing import List, Set
+from typing import Dict, Iterable, Set
 
 CONFIG_IS_NOT_SET_PATTERN = r'^# CONFIG_(\w+) is not set$'
 CONFIG_PATTERN = r'^CONFIG_(\w+)=(\S+|".*")$'
@@ -32,35 +32,42 @@ class Kconfig:
 	"""Represents defconfig or .config specified using the Kconfig language."""
 
 	def __init__(self) -> None:
-		self._entries = []  # type: List[KconfigEntry]
+		self._entries = {}  # type: Dict[str, str]
 
-	def entries(self) -> Set[KconfigEntry]:
-		return set(self._entries)
+	def __eq__(self, other) -> bool:
+		if not isinstance(other, self.__class__):
+			return False
+		return self._entries == other._entries
 
-	def add_entry(self, entry: KconfigEntry) -> None:
-		self._entries.append(entry)
+	def __repr__(self) -> str:
+		return ','.join(str(e) for e in self.as_entries())
+
+	def as_entries(self) -> Iterable[KconfigEntry]:
+		for name, value in self._entries.items():
+			yield KconfigEntry(name, value)
+
+	def add_entry(self, name: str, value: str) -> None:
+		self._entries[name] = value
 
 	def is_subset_of(self, other: 'Kconfig') -> bool:
-		other_dict = {e.name: e.value for e in other.entries()}
-		for a in self.entries():
-			b = other_dict.get(a.name)
+		for name, value in self._entries.items():
+			b = other._entries.get(name)
 			if b is None:
-				if a.value == 'n':
+				if value == 'n':
 					continue
 				return False
-			if a.value != b:
+			if value != b:
 				return False
 		return True
 
 	def merge_in_entries(self, other: 'Kconfig') -> None:
-		if other.is_subset_of(self):
-			return
-		self._entries = list(self.entries().union(other.entries()))
+		for name, value in other._entries.items():
+			self._entries[name] = value
 
 	def write_to_file(self, path: str) -> None:
 		with open(path, 'a+') as f:
-			for entry in self.entries():
-				f.write(str(entry) + '\n')
+			for e in self.as_entries():
+				f.write(str(e) + '\n')
 
 def parse_file(path: str) -> Kconfig:
 	with open(path, 'r') as f:
@@ -78,14 +85,12 @@ def parse_from_string(blob: str) -> Kconfig:
 
 		match = config_matcher.match(line)
 		if match:
-			entry = KconfigEntry(match.group(1), match.group(2))
-			kconfig.add_entry(entry)
+			kconfig.add_entry(match.group(1), match.group(2))
 			continue
 
 		empty_match = is_not_set_matcher.match(line)
 		if empty_match:
-			entry = KconfigEntry(empty_match.group(1), 'n')
-			kconfig.add_entry(entry)
+			kconfig.add_entry(empty_match.group(1), 'n')
 			continue
 
 		if line[0] == '#':