[systemtest] Allow using find_in_uart0() without filter
Previously, if `None` was passed to `find_in_uart0()` it always used the
default filter, which strips message prefixes produced by `LOG_*()`
macros in OpenTitan.
After this patch, passing `None` results in no filter being applied.
Not passing any argument uses the default filter.
Additionally, some lint fixes.
Signed-off-by: Philipp Wagner <phw@lowrisc.org>
diff --git a/test/systemtest/utils.py b/test/systemtest/utils.py
index a22773b..250392d 100644
--- a/test/systemtest/utils.py
+++ b/test/systemtest/utils.py
@@ -464,7 +464,8 @@
1. A regular expression (any object with a match attribute, or a re.Pattern
object in Python 3.7+). In this case, the pattern is matched against all
lines and the result of re.match(pattern) (a re.Match object since
- Python 3.7) is returned.
+ Python 3.7) is returned. Note that re.match() always matches from the
+ beginning of the line.
2. A string. In this case pattern is compared to each line with
startswith(), and the full matching line is returned on a match.
If no match is found None is returned.
