test-lib: bring $remove_trash out of retirement

There's no point in creating a repository or directory only to decide
right afterwards that we're skipping all the tests. We can save
ourselves the redundant "git init" or "mkdir" and "rm -rf" in this
case.

We carry around the "$remove_trash" variable because if the directory
is unexpectedly gone at test_done time we'll still want to hit the
"trash directory already removed" error, but not if we never created
the trash directory. See df4c0d1 (test-lib: abort when can't
remove trash directory, 2017-04-20) for the addition of that error.

So let's partially revert 06478da (test-lib: retire $remove_trash
variable, 2017-04-23) and move the decision about whether to skip all
tests earlier.

Let's also fix a bug that was with us since abc5d37 (Enable
parallel tests, 2008-08-08): we would leak $remove_trash from the
environment. We don't want this to error out, so let's reset it to the
empty string first:

     remove_trash=t GIT_SKIP_TESTS=t0001 ./t0001-init.sh

I tested this with --debug, see 4d0912a (test-lib.sh: do not barf
under --debug at the end of the test, 2017-04-24) for a bug we don't
want to re-introduce.

While I'm at it, let's move the HOME assignment to just before
test_create_repo, it could be lower, but it seems better to set it
before calling anything in test-lib-functions.sh

Signed-off-by: Ævar Arnfjörð Bjarmason <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: avar

t/test-lib.sh

@@ -1167,7 +1167,7 @@ test_done () {
 			esac
 		fi
 
-		if test -z "$debug"
+		if test -z "$debug" && test -n "$remove_trash"
 		then
 			test -d "$TRASH_DIRECTORY" ||
 			error "Tests passed but trash directory already removed before test cleanup; aborting"
@@ -1332,17 +1332,30 @@ then
 	exit 1
 fi
 
+# Are we running this test at all?
+remove_trash=
+this_test=${0##*/}
+this_test=${this_test%%-*}
+if match_pattern_list "$this_test" $GIT_SKIP_TESTS
+then
+	say_color info >&3 "skipping test $this_test altogether"
+	skip_all="skip all tests in $this_test"
+	test_done
+fi
+
+# Last-minute variable setup
+HOME="$TRASH_DIRECTORY"
+GNUPGHOME="$HOME/gnupg-home-not-used"
+export HOME GNUPGHOME
+
 # Test repository
 rm -fr "$TRASH_DIRECTORY" || {
 	GIT_EXIT_OK=t
 	echo >&5 "FATAL: Cannot prepare test area"
 	exit 1
 }
 
-HOME="$TRASH_DIRECTORY"
-GNUPGHOME="$HOME/gnupg-home-not-used"
-export HOME GNUPGHOME
-
+remove_trash=t
 if test -z "$TEST_NO_CREATE_REPO"
 then
 	test_create_repo "$TRASH_DIRECTORY"
@@ -1354,15 +1367,6 @@ fi
 # in subprocesses like git equals our $PWD (for pathname comparisons).
 cd -P "$TRASH_DIRECTORY" || exit 1
 
-this_test=${0##*/}
-this_test=${this_test%%-*}
-if match_pattern_list "$this_test" $GIT_SKIP_TESTS
-then
-	say_color info >&3 "skipping test $this_test altogether"
-	skip_all="skip all tests in $this_test"
-	test_done
-fi
-
 if test -n "$write_junit_xml"
 then
 	junit_xml_dir="$TEST_OUTPUT_DIRECTORY/out"