diff --git a/test/T010-help-test.sh b/test/T010-help-test.sh
index da45d3ae..1fbc46a2 100755
--- a/test/T010-help-test.sh
+++ b/test/T010-help-test.sh
@@ -12,7 +12,7 @@ test_expect_success 'notmuch help'
 test_begin_subtest 'notmuch --version'
 test_expect_success 'notmuch --version'
 
-if [ $NOTMUCH_HAVE_MAN -eq 1 ]; then
+if [ "${NOTMUCH_HAVE_MAN-0}" = "1" ]; then
     test_begin_subtest 'notmuch --help tag'
     test_expect_success 'notmuch --help tag'
 
diff --git a/test/T060-count.sh b/test/T060-count.sh
index 48146706..6e855b59 100755
--- a/test/T060-count.sh
+++ b/test/T060-count.sh
@@ -157,7 +157,7 @@ print("4: {} messages".format(query.count_messages()))
 EOF
 test_expect_equal_file EXPECTED OUTPUT
 
-if [ $NOTMUCH_HAVE_SFSEXP -eq 1 ]; then
+if [ "${NOTMUCH_HAVE_SFSEXP-0}" = "1" ]; then
 
     test_begin_subtest "and of exact terms (query=sexp)"
     output=$(notmuch count --query=sexp '(and "wonderful" "wizard")')
diff --git a/test/T081-sexpr-search.sh b/test/T081-sexpr-search.sh
index 0c7db9c2..8800b545 100755
--- a/test/T081-sexpr-search.sh
+++ b/test/T081-sexpr-search.sh
@@ -2,7 +2,7 @@
 test_description='"notmuch search" in several variations'
 . $(dirname "$0")/test-lib.sh || exit 1
 
-if [ $NOTMUCH_HAVE_SFSEXP -ne 1 ]; then
+if [ "${NOTMUCH_HAVE_SFSEXP-0}" != "1" ]; then
     printf "Skipping due to missing sfsexp library\n"
     test_done
 fi
diff --git a/test/T095-address.sh b/test/T095-address.sh
index 8bb3627a..0cafbe20 100755
--- a/test/T095-address.sh
+++ b/test/T095-address.sh
@@ -325,7 +325,7 @@ cat <<EOF >EXPECTED
 EOF
 test_expect_equal_file EXPECTED OUTPUT
 
-if [[ NOTMUCH_HAVE_SFSEXP = 1 ]]; then
+if [ "${NOTMUCH_HAVE_SFSEXP-0}" = "1" ]; then
     test_begin_subtest "sexpr query: all messages"
     notmuch address '*' > EXPECTED
     notmuch address --query=sexp '()' > OUTPUT
diff --git a/test/T150-tagging.sh b/test/T150-tagging.sh
index ac3f2539..273c0af3 100755
--- a/test/T150-tagging.sh
+++ b/test/T150-tagging.sh
@@ -328,7 +328,7 @@ test_expect_equal "$output" "A Xapian exception occurred opening database"
 
 add_email_corpus
 
-if [ $NOTMUCH_HAVE_SFSEXP -eq 1 ]; then
+if [ "${NOTMUCH_HAVE_SFSEXP-0}" = "1" ]; then
 
     test_query_syntax '(and "wonderful" "wizard")' 'wonderful and wizard'
     test_query_syntax '(or "php" "wizard")' 'php or wizard'
diff --git a/test/T160-json.sh b/test/T160-json.sh
index 4a797f6a..f61c3f2d 100755
--- a/test/T160-json.sh
+++ b/test/T160-json.sh
@@ -66,7 +66,7 @@ test_expect_equal_json "$output" "[{\"thread\": \"XXX\",
  \"unread\"]}]"
 
 test_begin_subtest "Search message: json, 64-bit timestamp"
-if [ $NOTMUCH_HAVE_64BIT_TIME_T -ne 1 ]; then
+if [ "${NOTMUCH_HAVE_64BIT_TIME_T-0}" != "1" ]; then
     test_subtest_known_broken
 fi
 add_message "[subject]=\"json-search-64bit-timestamp-subject\"" "[date]=\"Tue, 01 Jan 2999 12:00:00 -0000\"" "[body]=\"json-search-64bit-timestamp-message\""
diff --git a/test/T220-reply.sh b/test/T220-reply.sh
index 207f5788..120d7138 100755
--- a/test/T220-reply.sh
+++ b/test/T220-reply.sh
@@ -24,7 +24,7 @@ test_begin_subtest "Basic reply"
 notmuch reply id:${gen_msg_id} >OUTPUT 2>&1 && echo OK >> OUTPUT
 test_expect_equal_file basic.expected OUTPUT
 
-if [ $NOTMUCH_HAVE_SFSEXP -eq 1 ]; then
+if [ "${NOTMUCH_HAVE_SFSEXP-0}" = "1" ]; then
 
     test_begin_subtest "Basic reply (query=sexp)"
     notmuch reply --query=sexp "(id ${gen_msg_id})" >OUTPUT 2>&1 && echo OK >> OUTPUT
diff --git a/test/T240-dump-restore.sh b/test/T240-dump-restore.sh
index a86f0fb7..80939030 100755
--- a/test/T240-dump-restore.sh
+++ b/test/T240-dump-restore.sh
@@ -118,7 +118,7 @@ notmuch dump -- from:cworth > dump-dash-cworth.actual
 test_expect_equal_file dump-cworth.expected dump-dash-cworth.actual
 
 
-if [ $NOTMUCH_HAVE_SFSEXP -eq 1 ]; then
+if [ "${NOTMUCH_HAVE_SFSEXP-0}" = "1" ]; then
 
     test_begin_subtest "dump --query=sexp -- '(from cworth)'"
     notmuch dump --query=sexp -- '(from cworth)' > dump-dash-cworth.actual2
diff --git a/test/T355-smime.sh b/test/T355-smime.sh
index 809274ce..3bd5a17e 100755
--- a/test/T355-smime.sh
+++ b/test/T355-smime.sh
@@ -184,7 +184,7 @@ output=$(notmuch show --format=json id:smime-onepart-signed@protected-headers.ex
 test_valid_json "$output"
 
 test_begin_subtest "Verify signature on PKCS#7 SignedData message"
-if [ $NOTMUCH_HAVE_64BIT_TIME_T -ne 1 ]; then
+if [ "${NOTMUCH_HAVE_64BIT_TIME_T-0}" != "1" ]; then
     test_subtest_known_broken
 fi
 output=$(notmuch show --format=json id:smime-onepart-signed@protected-headers.example)
diff --git a/test/T391-python-cffi.sh b/test/T391-python-cffi.sh
index 30872af0..0ef9e0d3 100755
--- a/test/T391-python-cffi.sh
+++ b/test/T391-python-cffi.sh
@@ -2,11 +2,10 @@
 test_description="python bindings (pytest)"
 . $(dirname "$0")/test-lib.sh || exit 1
 
-if [ $NOTMUCH_HAVE_PYTHON3_CFFI -eq 0 -o $NOTMUCH_HAVE_PYTHON3_PYTEST -eq 0 ]; then
+if [ "${NOTMUCH_HAVE_PYTHON3_CFFI-0}" = "0" -o "${NOTMUCH_HAVE_PYTHON3_PYTEST-0}" = "0" ]; then
     test_done
 fi
 
-
 test_begin_subtest "python cffi tests (NOTMUCH_CONFIG set)"
 pytest_dir=$NOTMUCH_BUILDDIR/bindings/python-cffi/build/stage
 printf "[pytest]\nminversion = 3.0\naddopts = -ra\n" > $pytest_dir/pytest.ini
diff --git a/test/T392-python-cffi-notmuch.sh b/test/T392-python-cffi-notmuch.sh
index 15c8fc6b..06161219 100755
--- a/test/T392-python-cffi-notmuch.sh
+++ b/test/T392-python-cffi-notmuch.sh
@@ -2,7 +2,7 @@
 test_description="python bindings (notmuch test suite)"
 . $(dirname "$0")/test-lib.sh || exit 1
 
-if [ $NOTMUCH_HAVE_PYTHON3_CFFI -eq 0 -o $NOTMUCH_HAVE_PYTHON3_PYTEST -eq 0 ]; then
+if [ "${NOTMUCH_HAVE_PYTHON3_CFFI-0}" = "0" -o "${NOTMUCH_HAVE_PYTHON3_PYTEST-0}" = "0" ]; then
     test_done
 fi
 
diff --git a/test/T520-show.sh b/test/T520-show.sh
index c7b73a6d..6bcf109c 100755
--- a/test/T520-show.sh
+++ b/test/T520-show.sh
@@ -35,7 +35,7 @@ notmuch show --entire-thread=true --sort=oldest-first $QUERY > OUTPUT
 test_expect_equal_file EXPECTED OUTPUT
 
 
-if [ $NOTMUCH_HAVE_SFSEXP -eq 1 ]; then
+if [ "${NOTMUCH_HAVE_SFSEXP-0}" = "1" ]; then
 
     test_query_syntax '(and "wonderful" "wizard")' 'wonderful and wizard'
     test_query_syntax '(or "php" "wizard")' 'php or wizard'
diff --git a/test/T570-revision-tracking.sh b/test/T570-revision-tracking.sh
index a7480050..bcc97dd9 100755
--- a/test/T570-revision-tracking.sh
+++ b/test/T570-revision-tracking.sh
@@ -95,7 +95,7 @@ subtotal=$(notmuch count lastmod:..$lastmod)
 result=$(($subtotal == $total-1))
 test_expect_equal 1 "$result"
 
-if [ $NOTMUCH_HAVE_SFSEXP -eq 1 ]; then
+if [ "${NOTMUCH_HAVE_SFSEXP-0}" = "1" ]; then
     test_begin_subtest 'exclude one message using negative lastmod (sexp)'
     total=$(notmuch count '*')
     notmuch tag +${RANDOM} id:4EFC743A.3060609@april.org
diff --git a/test/T700-reindex.sh b/test/T700-reindex.sh
index 347f8483..af34ad7c 100755
--- a/test/T700-reindex.sh
+++ b/test/T700-reindex.sh
@@ -5,7 +5,7 @@ test_description='reindexing messages'
 add_email_corpus
 
 
-if [ $NOTMUCH_HAVE_SFSEXP -eq 1 ]; then
+if [ "${NOTMUCH_HAVE_SFSEXP-0}" = "1" ]; then
 
     count=$(notmuch count --lastmod '*' | cut -f 3)
     for query in '()' '(not)' '(and)' '(or ())' '(or (not))' '(or (and))' \
diff --git a/test/T800-asan.sh b/test/T800-asan.sh
index 5055c93e..7c28dc7c 100755
--- a/test/T800-asan.sh
+++ b/test/T800-asan.sh
@@ -2,7 +2,7 @@
 test_description='run code with ASAN enabled against the library'
 . $(dirname "$0")/test-lib.sh || exit 1
 
-if [ $NOTMUCH_HAVE_ASAN -ne 1 ]; then
+if [ "${NOTMUCH_HAVE_ASAN-0}" != "1" ]; then
     printf "Skipping due to missing ASAN support\n"
     test_done
 fi
diff --git a/test/T810-tsan.sh b/test/T810-tsan.sh
index 7e877b27..4071e296 100755
--- a/test/T810-tsan.sh
+++ b/test/T810-tsan.sh
@@ -8,7 +8,7 @@ test_description='run code with TSan enabled against the library'
 
 . "$test_directory"/test-lib.sh || exit 1
 
-if [ $NOTMUCH_HAVE_TSAN -ne 1 ]; then
+if [ "${NOTMUCH_HAVE_TSAN-0}" != "1" ]; then
     printf "Skipping due to missing TSan support\n"
     test_done
 fi
diff --git a/test/T850-git.sh b/test/T850-git.sh
index 55cec78a..be6e0cd4 100755
--- a/test/T850-git.sh
+++ b/test/T850-git.sh
@@ -2,7 +2,7 @@
 test_description='"notmuch git" to save and restore tags'
 . $(dirname "$0")/test-lib.sh || exit 1
 
-if [ $NOTMUCH_HAVE_SFSEXP -ne 1 ]; then
+if [ "${NOTMUCH_HAVE_SFSEXP-0}" != "1" ]; then
     printf "Skipping due to missing sfsexp library\n"
     test_done
 fi