perf: export some important test-lib variables

The only bug right now is that $GIT_TEST_CMP is needed for test_cmp to
work.

However, we also export the three most important paths for tests:

  TEST_DIRECTORY
  TRASH_DIRECTORY
  GIT_BUILD_DIR

Since they are available within test_expect_success, a future test
writer may expect them to also be defined in test_perf.

Signed-off-by: Thomas Rast <trast@student.ethz.ch>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/perf/p0000-perf-lib-sanity.sh

@@ -38,9 +38,18 @@ test_expect_success 'test_export works with weird vars' '
 	test "$bar" = "weird # variable"
 '
 
+test_perf 'important variables available in subshells' '
+	test -n "$HOME" &&
+	test -n "$TEST_DIRECTORY" &&
+	test -n "$TRASH_DIRECTORY" &&
+	test -n "$GIT_BUILD_DIR"
+'
+
 test_perf 'test-lib-functions correctly loaded in subshells' '
 	: >a &&
-	test_path_is_file a
+	test_path_is_file a &&
+	: >b &&
+	test_cmp a b
 '
 
 test_done

t/perf/perf-lib.sh

@@ -45,6 +45,10 @@ TEST_NO_CREATE_REPO=t
 
 . ../test-lib.sh
 
+# Variables from test-lib that are normally internal to the tests; we
+# need to export them for test_perf subshells
+export TEST_DIRECTORY TRASH_DIRECTORY GIT_BUILD_DIR GIT_TEST_CMP
+
 perf_results_dir=$TEST_OUTPUT_DIRECTORY/test-results
 mkdir -p "$perf_results_dir"
 rm -f "$perf_results_dir"/$(basename "$0" .sh).subtests