Reorganize tests

* Split out test helper functions into tools/test_functions.sh
  * bin/_blackbox_common_test.sh: Unit-tests for functions.
  * blackbox_postdeploy: Use cp_permissions instead of chmod --reference

bin/_blackbox_common_test.sh

@@ -0,0 +1,23 @@
+#!/usr/bin/env bash
+
+#
+# _blackbox_common_test.sh -- Unit tests of functions from _blackbox_common.sh
+#
+
+set -e
+. "${0%/*}/_blackbox_common.sh"
+. tools/test_functions.sh
+
+PHASE 'Test cp-permissions: TestA'
+touch TestA TestB TestC TestD
+chmod 0347 TestA
+chmod 0700 TestB
+chmod 0070 TestC
+chmod 0070 TestD
+cp_permissions TestA TestB TestC
+assert_file_perm '--wxr--rwx' TestA
+assert_file_perm '--wxr--rwx' TestB
+assert_file_perm '--wxr--rwx' TestC
+assert_file_perm '----rwx---' TestD
+
+echo '========== DONE.'