t0000: simplify HARNESS_ACTIVE hack

Commit 517cd55 set HARNESS_ACTIVE unconditionally in
sub-tests, because that value affects the output of
"--verbose". t0000 needs stable output from its sub-tests,
and we may or may not be running under a TAP harness.

That commit made the decision to always set the variable,
since it has another useful side effect, which is
suppressing writes to t/test-results by the sub-tests (which
would just pollute the real results).

Since the last commit, though, the sub-tests have their own
test-results directories, so this is no longer an issue. We
can now update a few comments that are no longer accurate
nor necessary.

We can also revisit the choice of HARNESS_ACTIVE. Since we
must choose one value for stability, it's probably saner to
have it off. This means that future patches could test
things like the test-results writing, or the "--quiet"
option, which is currently ignored when run under a harness.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t0000-basic.sh

@@ -50,11 +50,11 @@ run_sub_test_lib_test () {
 	shift 2
 	mkdir "$name" &&
 	(
-		# Pretend we're a test harness.  This prevents
-		# test-lib from writing the counts to a file that will
-		# later be summarized, showing spurious "failed" tests
-		HARNESS_ACTIVE=t &&
-		export HARNESS_ACTIVE &&
+		# Pretend we're not running under a test harness, whether we
+		# are or not. The test-lib output depends on the setting of
+		# this variable, so we need a stable setting under which to run
+		# the sub-test.
+		sane_unset HARNESS_ACTIVE &&
 		cd "$name" &&
 		cat >"$name.sh" <<-EOF &&
 		#!$SHELL_PATH
@@ -235,16 +235,13 @@ test_expect_success 'test --verbose' '
 	grep -v "^Initialized empty" test-verbose/out+ >test-verbose/out &&
 	check_sub_test_lib_test test-verbose <<-\EOF
 	> expecting success: true
-	> Z
 	> ok 1 - passing test
 	> Z
 	> expecting success: echo foo
 	> foo
-	> Z
 	> ok 2 - test with output
 	> Z
 	> expecting success: false
-	> Z
 	> not ok 3 - failing test
 	> #	false
 	> Z
@@ -267,7 +264,6 @@ test_expect_success 'test --verbose-only' '
 	> Z
 	> expecting success: echo foo
 	> foo
-	> Z
 	> ok 2 - test with output
 	> Z
 	> not ok 3 - failing test

t/test-lib.sh

@@ -477,8 +477,6 @@ test_at_end_hook_ () {
 test_done () {
 	GIT_EXIT_OK=t
 
-	# Note: t0000 relies on $HARNESS_ACTIVE disabling the .counts
-	# output file
 	if test -z "$HARNESS_ACTIVE"
 	then
 		test_results_dir="$TEST_OUTPUT_DIRECTORY/test-results"