scripts/resulttool: do not count newly passing tests as regressions

resulttool regression module simply compare a base test status to a target test
result status. This approach raises many false positives since all XXX -> PASS
transitions (XXX being any status different from PASS) are flagged as
regression.

- Do not list XXX -> PASS transitions in regression  report, instead count them
  and print a summary of "newly passing tests"
- If an inspected pair has only "newly passing tests", do not print detailed
  list and print it as "Improvement" instead of "Regression"

Updated output example looks like the following:
[...]
Improvement: oeselftest_fedora-37_qemux86-64_20230127010225
             oeselftest_ubuntu-22.04_qemux86-64_20230226120516
             (+1 test(s) passing)
[...]
Match:       oeselftest_almalinux-8.7_qemuarm64_20230127015830
             oeselftest_almalinux-8.7_qemuarm64_20230227015258
[...]
Regression:  oeselftest_almalinux-9.1_qemumips_20230127000217
             oeselftest_opensuseleap-15.4_qemumips_20230226130046
    ptestresult.glibc-user.debug/tst-read-chk-cancel: PASS -> None
    ptestresult.glibc-user.nptl/tst-mutexpi4: PASS -> FAIL
    ptestresult.glibc-user.nptl/tst-mutexpi5a: PASS -> FAIL
    Additionally, 44 previously failing test(s) is/are now passing

Signed-off-by: Alexis Lothoré <alexis.lothore@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 14 insertions, 5 deletions

diff --git a/scripts/lib/resulttool/regression.py b/scripts/lib/resulttool/regression.py
index d7f0b16ca9..1facbcd85e 100644
--- a/scripts/lib/resulttool/regression.py
+++ b/scripts/lib/resulttool/regression.py
@@ -190,11 +190,20 @@ def compare_result(logger, base_name, target_name, base_result, target_result):
             else:
                 logger.error('Failed to retrieved base test case status: %s' % k)
     if result:
-        resultstring = "Regression: %s\n            %s\n" % (base_name, target_name)
-        for k in sorted(result):
-            resultstring += '    %s: %s -> %s\n' % (k, result[k]['base'], result[k]['target'])
+        new_pass_count = sum(test['target'] is not None and test['target'].startswith("PASS") for test in result.values())
+        # Print a regression report only if at least one test has a regression status (FAIL, SKIPPED, absent...)
+        if new_pass_count < len(result):
+            resultstring = "Regression:  %s\n             %s\n" % (base_name, target_name)
+            for k in sorted(result):
+                if not result[k]['target'] or not result[k]['target'].startswith("PASS"):
+                    resultstring += '    %s: %s -> %s\n' % (k, result[k]['base'], result[k]['target'])
+            if new_pass_count > 0:
+                resultstring += f'    Additionally, {new_pass_count} previously failing test(s) is/are now passing\n'
+        else:
+            resultstring = "Improvement: %s\n             %s\n             (+%d test(s) passing)" % (base_name, target_name, new_pass_count)
+            result = None
     else:
-        resultstring = "Match: %s\n       %s" % (base_name, target_name)
+        resultstring = "Match:       %s\n             %s" % (base_name, target_name)
     return result, resultstring
 
 def get_results(logger, source):
@@ -269,9 +278,9 @@ def regression_common(args, logger, base_results, target_results):
         else:
             notfound.append("%s not found in target" % a)
     print("\n".join(sorted(matches)))
+    print("\n")
     print("\n".join(sorted(regressions)))
     print("\n".join(sorted(notfound)))
-
     return 0
 
 def regression_git(args, logger):