test: add known broken test for n_directory_get_child_directories

Start a new test file (for the notmuch_directory_* API group) to hold
this test.

test/T563-lib-directory.sh

@@ -0,0 +1,61 @@
+#!/usr/bin/env bash
+test_description="notmuch_directory_* API"
+
+. $(dirname "$0")/test-lib.sh || exit 1
+
+add_email_corpus
+
+test_begin_subtest "building database"
+test_expect_success "NOTMUCH_NEW"
+
+cat <<EOF > c_head
+#include <stdio.h>
+#include <notmuch.h>
+#include <notmuch-test.h>
+#include <talloc.h>
+int main (int argc, char** argv)
+{
+   notmuch_database_t *db;
+   notmuch_directory_t *dir;
+   notmuch_status_t stat = NOTMUCH_STATUS_SUCCESS;
+   char *msg = NULL;
+
+   stat = notmuch_database_open_verbose (argv[1], NOTMUCH_DATABASE_MODE_READ_WRITE, &db, &msg);
+   if (stat != NOTMUCH_STATUS_SUCCESS) {
+     fprintf (stderr, "error opening database: %d %s\n", stat, msg ? msg : "");
+     exit (1);
+   }
+
+   EXPECT0(notmuch_database_get_directory (db, "bar", &dir));
+   EXPECT0(notmuch_database_close (db));
+EOF
+
+cat <<'EOF' > c_tail
+   if (stat) {
+       const char *stat_str = notmuch_database_status_string (db);
+       if (stat_str)
+           fputs (stat_str, stderr);
+    }
+
+}
+EOF
+
+test_begin_subtest "get child directories for a closed db"
+test_subtest_known_broken
+cat c_head - c_tail <<'EOF' | test_C ${MAIL_DIR}
+    {
+        notmuch_filenames_t *children;
+        children = notmuch_directory_get_child_directories (dir);
+        printf ("%d\n", children == NULL);
+        stat = NOTMUCH_STATUS_XAPIAN_EXCEPTION;
+    }
+EOF
+cat <<EOF > EXPECTED
+== stdout ==
+1
+== stderr ==
+A Xapian exception occurred at lib/directory.cc:XXX: Database has been closed
+EOF
+test_expect_equal_file EXPECTED OUTPUT
+
+test_done