From 095e9ec07ea66ff0deedc804c4234555ecbad74c Mon Sep 17 00:00:00 2001
From: Johannes Schindelin <johannes.schindelin@gmx.de>
Date: Fri, 31 Aug 2018 15:40:14 +0200
Subject: [PATCH] tests: include detailed trace logs with --write-junit-xml
 upon failure

The JUnit XML format lends itself to be presented in a powerful UI,
where you can drill down to the information you are interested in very
quickly.

For test failures, this usually means that you want to see the detailed
trace of the failing tests.

With Travis CI, we passed the `--verbose-log` option to get those
traces. However, that seems excessive, as we do not need/use the logs in
almost all of those cases: only when a test fails do we have a way to
include the trace.

So let's do something different when using Azure DevOps: let's run all
the tests with `--quiet` first, and only if a failure is encountered,
try to trace the commands as they are executed.

Of course, we cannot turn on `--verbose-log` after the fact. So let's
just re-run the test with all the same options, adding `--verbose-log`.
And then munging the output file into the JUnit XML on the fly.

Note: there is an off chance that re-running the test in verbose mode
"fixes" the failures (and this does happen from time to time!). That is
a possibility we should be able to live with. Ideally, we would label
this as "Passed upon rerun", and Azure Pipelines even know about that
outcome, but it is not available when using the JUnit XML format for
now:
https://github.com/Microsoft/azure-pipelines-agent/blob/master/src/Agent.Worker/TestResults/JunitResultReader.cs

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 t/test-lib.sh | 28 +++++++++++++++++++++++++++-
 1 file changed, 27 insertions(+), 1 deletion(-)

diff --git a/t/test-lib.sh b/t/test-lib.sh
index 394a08bfb1..5101720dbd 100644
--- a/t/test-lib.sh
+++ b/t/test-lib.sh
@@ -95,6 +95,13 @@ done,*)
 	test "$(cat "$BASE.exit")" = 0
 	exit
 	;;
+*' --write-junit-xml '*)
+	# record how to call this script *with* --verbose-log, in case
+	# we encounter a breakage
+	junit_rerun_options_sq="$(printf '%s\n' "$0" --verbose-log -x "$@" |
+		sed -e "s/'/'\\\\''/g" -e "s/^/'/" -e "s/\$/'/" |
+		tr '\012' ' ')"
+	;;
 esac
 
 # For repeatability, reset the environment to known value.
@@ -505,8 +512,18 @@ test_failure_ () {
 		junit_insert="<failure message=\"not ok $test_count -"
 		junit_insert="$junit_insert $(xml_attr_encode "$1")\">"
 		junit_insert="$junit_insert $(xml_attr_encode \
-			"$(printf '%s\n' "$@" | sed 1d)")"
+			"$(if test -n "$GIT_TEST_TEE_OUTPUT_FILE"
+			   then
+				cut -c "$GIT_TEST_TEE_OFFSET-" <"$GIT_TEST_TEE_OUTPUT_FILE"
+			   else
+				printf '%s\n' "$@" | sed 1d
+			   fi)")"
 		junit_insert="$junit_insert</failure>"
+		if test -n "$GIT_TEST_TEE_OUTPUT_FILE"
+		then
+			junit_insert="$junit_insert<system-err>$(xml_attr_encode \
+				"$(cat "$GIT_TEST_TEE_OUTPUT_FILE")")</system-err>"
+		fi
 		write_junit_xml_testcase "$1" "      $junit_insert"
 	fi
 	test_failure=$(($test_failure + 1))
@@ -885,6 +902,10 @@ write_junit_xml_testcase () {
 	write_junit_xml "$(printf '%s\n' \
 		"    <testcase $junit_attrs>" "$@" "    </testcase>")"
 	junit_have_testcase=t
+	if test -n "$GIT_TEST_TEE_OUTPUT_FILE"
+	then
+		GIT_TEST_TEE_OFFSET=$(perl -e 'print -s $ARGV[0]' "$GIT_TEST_TEE_OUTPUT_FILE")
+	fi
 }
 
 test_done () {
@@ -1175,6 +1196,11 @@ then
 		date +%Y-%m-%dT%H:%M:%S)\""
 	write_junit_xml --truncate "<testsuites>" "  <testsuite $junit_attrs>"
 	junit_suite_start=$(test-tool date getnanos)
+	if test -n "$GIT_TEST_TEE_OUTPUT_FILE"
+	then
+		GIT_TEST_TEE_OFFSET=0
+		GIT_TEST_TEE_ERR_OFFSET=0
+	fi
 fi
 
 # Provide an implementation of the 'yes' utility