I have just uploaded a NMU to fix this. debdiff is attached.
diff -Nru wit-3.01a/debian/changelog wit-3.01a/debian/changelog
--- wit-3.01a/debian/changelog 2021-11-11 13:57:57.000000000 +0100
+++ wit-3.01a/debian/changelog 2023-03-29 22:34:46.000000000 +0200
@@ -1,3 +1,10 @@
+wit (3.01a-4.1) unstable; urgency=medium
+
+ * Non-maintainer upload.
+ * Eliminate bashisms in autopkgtest. (Closes: #1033515)
+
+ -- Bastian Germann <b...@debian.org> Wed, 29 Mar 2023 22:34:46 +0200
+
wit (3.01a-4) unstable; urgency=medium
* Add autopkgtests. (Closes: #999455)
diff -Nru wit-3.01a/debian/tests/wdf-cat-test
wit-3.01a/debian/tests/wdf-cat-test
--- wit-3.01a/debian/tests/wdf-cat-test 2021-11-11 13:52:13.000000000 +0100
+++ wit-3.01a/debian/tests/wdf-cat-test 2023-03-29 21:51:58.000000000 +0200
@@ -4,6 +4,6 @@
res=$(wdf-cat "$AUTOPKGTEST_TMP/content")
-if [[ "$res" != "Hello, world" ]]; then
+if [ "$res" != "Hello, world" ]; then
exit 1
fi
diff -Nru wit-3.01a/debian/tests/wdf-test wit-3.01a/debian/tests/wdf-test
--- wit-3.01a/debian/tests/wdf-test 2021-11-11 13:52:27.000000000 +0100
+++ wit-3.01a/debian/tests/wdf-test 2023-03-29 21:51:15.000000000 +0200
@@ -4,6 +4,6 @@
res=$(wdf +CAT "$AUTOPKGTEST_TMP/content")
-if [[ "$res" != "Hello, world" ]]; then
+if [ "$res" != "Hello, world" ]; then
exit 1
fi
