diff --git a/configure.ac b/configure.ac
index c9a7ee5..dda8e2a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -132,6 +132,8 @@ fi
 AC_SUBST([OPTIONAL_LIBCURL_CFLAGS])
 AC_SUBST([OPTIONAL_LIBCURL_LIBS])
 
+AC_DEFINE_UNQUOTED([CA_BUNDLE_PATH], ["$(curl-config --ca 2>/dev/null)"], [CA bundle install path])
+
 AC_CONFIG_FILES([Makefile])
 AC_OUTPUT
 
diff --git a/osslsigncode.c b/osslsigncode.c
index e6ea54f..5edbad0 100644
--- a/osslsigncode.c
+++ b/osslsigncode.c
@@ -1919,7 +1919,7 @@ static int verify_timestamp(PKCS7 *p7, PKCS7 *tmstamp_p7, char *untrusted)
 	printf("TSA's certificates file: %s\n", untrusted);
 	store = X509_STORE_new();
 	if (!load_file_lookup(store, untrusted, NULL, X509_PURPOSE_TIMESTAMP_SIGN)) {
-		fprintf(stderr, "Failed to add timestamp store lookup file\n");
+		printf("\nUse the \"-untrusted\" option to add the CA cert bundle to verify timestamp server.\n");
 		ret = 1; /* FAILED */
 	}
 	verok = PKCS7_verify(tmstamp_p7, tmstamp_p7->d.sign->cert, store, 0, NULL, 0);
@@ -2971,6 +2971,10 @@ static char *get_cafile(void)
 	const char *sslpart1, *sslpart2;
 	char *cafile, *openssl_dir, *str_begin, *str_end;
 
+#ifdef CA_BUNDLE_PATH
+	if (strcmp(CA_BUNDLE_PATH, ""))
+		return OPENSSL_strdup(CA_BUNDLE_PATH);
+#endif
 	sslpart1 = OpenSSL_version(OPENSSL_DIR);
 	sslpart2 = "/certs/ca-bundle.crt";
 	str_begin = strchr(sslpart1, '"');
diff --git a/tests/certs/makecerts.sh b/tests/certs/makecerts.sh
index 52c973a..61bccc1 100755
--- a/tests/certs/makecerts.sh
+++ b/tests/certs/makecerts.sh
@@ -3,7 +3,7 @@
 result=0
 
 test_result() {
-  if [ "$1" == 0 ]
+  if test "$1" -eq 0
     then
       printf "Succeeded\n" >> "makecerts.log"
     else
@@ -139,9 +139,9 @@ make_certs() {
   test_result $?
 
 # copy new files
-  if [ -s tmp/CACert.pem ] && [ -s tmp/crosscert.pem ] && [ -s tmp/expired.pem ] && [ -s tmp/cert.pem ] && \
-    [ -s tmp/CACertCRL.pem ] && [ -s tmp/revoked.pem ] && [ -s tmp/key.pem ] && [ -s tmp/keyp.pem ] && \
-    [ -s tmp/key.der ] && [ -s tmp/cert.der ] && [ -s tmp/cert.spc ] && [ -s tmp/cert.p12 ]
+  if test -s tmp/CACert.pem -a -s tmp/crosscert.pem -a -s tmp/expired.pem -a -s tmp/cert.pem \
+    -a -s tmp/CACertCRL.pem -a -s tmp/revoked.pem -a -s tmp/key.pem -a -s tmp/keyp.pem \
+    -a -s tmp/key.der -a -s tmp/cert.der -a -s tmp/cert.spc -a -s tmp/cert.p12
   then
     cp tmp/* ./
     printf "%s\n" "keys & certificates successfully generated"
@@ -164,7 +164,7 @@ make_certs() {
 }
 
 # Tests requirement
-if [ -n "$(command -v faketime)" ]
+if test -n "$(command -v faketime)"
   then
     make_certs $1
     result=$?
diff --git a/tests/recipes/01_sign_pem b/tests/recipes/01_sign_pem
index 74369f2..987e16b 100644
--- a/tests/recipes/01_sign_pem
+++ b/tests/recipes/01_sign_pem
@@ -8,7 +8,7 @@ script_path=$(pwd)
 # PE file
 test_name="011. Sign a PE file with the certificate and private key files in the PEM format"
 printf "\n%s\n" "$test_name"
-if [ -s "test.exe" ]
+if test -s "test.exe"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
@@ -24,7 +24,7 @@ if [ -s "test.exe" ]
 # CAB file
 test_name="012. Sign a CAB file with the certificate and private key files in the PEM format"
 printf "\n%s\n" "$test_name"
-if [ -s "test.ex_" ]
+if test -s "test.ex_"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
@@ -40,7 +40,7 @@ if [ -s "test.ex_" ]
 # MSI file
 test_name="013. Sign a MSI file with the certificate and private key files in the PEM format"
 printf "\n%s\n" "$test_name"
-if [ -s "sample.msi" ]
+if test -s "sample.msi"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
diff --git a/tests/recipes/02_sign_pass b/tests/recipes/02_sign_pass
index 98c87ca..860fed1 100644
--- a/tests/recipes/02_sign_pass
+++ b/tests/recipes/02_sign_pass
@@ -7,7 +7,7 @@ script_path=$(pwd)
 # PE file
 test_name="021. Sign a PE file with the encrypted private key file in the PEM format"
 printf "\n%s\n" "$test_name"
-if [ -s "test.exe" ]
+if test -s "test.exe"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
@@ -24,7 +24,7 @@ if [ -s "test.exe" ]
 # CAB file
 test_name="022. Sign a CAB file with the encrypted private key file in the PEM format"
 printf "\n%s\n" "$test_name"
-if [ -s "test.ex_" ]
+if test -s "test.ex_"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
@@ -41,7 +41,7 @@ if [ -s "test.ex_" ]
 # MSI file
 test_name="023. Sign a MSI file with the encrypted private key file in the PEM format"
 printf "\n%s\n" "$test_name"
-if [ -s "sample.msi" ]
+if test -s "sample.msi"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
diff --git a/tests/recipes/03_sign_der b/tests/recipes/03_sign_der
index e9fbfce..49b4150 100644
--- a/tests/recipes/03_sign_der
+++ b/tests/recipes/03_sign_der
@@ -8,7 +8,7 @@ script_path=$(pwd)
 # PE file
 test_name="031. Sign a PE file with the encrypted private key file in the DER format"
 printf "\n%s\n" "$test_name"
-if [ -s "test.exe" ]
+if test -s "test.exe"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
@@ -25,7 +25,7 @@ if [ -s "test.exe" ]
 # CAB file
 test_name="032. Sign a CAB file with the encrypted private key file in the DER format"
 printf "\n%s\n" "$test_name"
-if [ -s "test.ex_" ]
+if test -s "test.ex_"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
@@ -42,7 +42,7 @@ if [ -s "test.ex_" ]
 # MSI file
 test_name="033. Sign a MSI file with the encrypted private key file in the DER format"
 printf "\n%s\n" "$test_name"
-if [ -s "sample.msi" ]
+if test -s "sample.msi"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
diff --git a/tests/recipes/04_sign_spc b/tests/recipes/04_sign_spc
index e04c235..3bf4bf0 100644
--- a/tests/recipes/04_sign_spc
+++ b/tests/recipes/04_sign_spc
@@ -8,7 +8,7 @@ script_path=$(pwd)
 # PE file
 test_name="041. Sign a PE file a SPC certificate file"
 printf "\n%s\n" "$test_name"
-if [ -s "test.exe" ]
+if test -s "test.exe"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
@@ -25,7 +25,7 @@ if [ -s "test.exe" ]
 # CAB file
 test_name="042. Sign a CAB file a SPC certificate file"
 printf "\n%s\n" "$test_name"
-if [ -s "test.ex_" ]
+if test -s "test.ex_"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
@@ -42,7 +42,7 @@ if [ -s "test.ex_" ]
 # MSI file
 test_name="043. Sign a MSI file a SPC certificate file"
 printf "\n%s\n" "$test_name"
-if [ -s "sample.msi" ]
+if test -s "sample.msi"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
diff --git a/tests/recipes/05_sign_pkcs12 b/tests/recipes/05_sign_pkcs12
index 6e212fa..381a56f 100644
--- a/tests/recipes/05_sign_pkcs12
+++ b/tests/recipes/05_sign_pkcs12
@@ -7,7 +7,7 @@ script_path=$(pwd)
 # PE file
 test_name="051. Sign a PE file with a certificate and key stored in a PKCS#12 container"
 printf "\n%s\n" "$test_name"
-if [ -s "test.exe" ]
+if test -s "test.exe"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
@@ -23,7 +23,7 @@ if [ -s "test.exe" ]
 # CAB file
 test_name="052. Sign a CAB file with a certificate and key stored in a PKCS#12 container"
 printf "\n%s\n" "$test_name"
-if [ -s "test.ex_" ]
+if test -s "test.ex_"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
@@ -40,7 +40,7 @@ if [ -s "test.ex_" ]
 # MSI file
 test_name="053. Sign a MSI file with a certificate and key stored in a PKCS#12 container"
 printf "\n%s\n" "$test_name"
-if [ -s "sample.msi" ]
+if test -s "sample.msi"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
diff --git a/tests/recipes/06_test_sha256sum b/tests/recipes/06_test_sha256sum
index 8197c39..ad79ad5 100644
--- a/tests/recipes/06_test_sha256sum
+++ b/tests/recipes/06_test_sha256sum
@@ -6,9 +6,9 @@ res=0
 skip=0
 test_name="061. Checking SHA256 message digests for 01x-05x tests"
 printf "\n%s\n" "$test_name"
-if [ -s "test.exe" ]
+if test -s "test.exe"
   then
-    if [ $(cat "sha256sum_exe.log" | cut -d' ' -f1 | uniq | wc -l) -ne 1 ]
+    if test $(cat "sha256sum_exe.log" | cut -d' ' -f1 | uniq | wc -l) -ne 1
       then
         res=1
         cat "sha256sum_exe.log" >> "results.log"
@@ -21,9 +21,9 @@ if [ -s "test.exe" ]
     skip=$(($skip+1))
   fi
 
-if [ -s "test.ex_" ]
+if test -s "test.ex_"
   then
-    if [ $(cat "sha256sum_ex_.log" | cut -d' ' -f1 | uniq | wc -l) -ne 1 ]
+    if test $(cat "sha256sum_ex_.log" | cut -d' ' -f1 | uniq | wc -l) -ne 1
       then
         res=1
         cat "sha256sum_ex_.log" >> "results.log"
@@ -36,9 +36,9 @@ if [ -s "test.ex_" ]
     skip=$(($skip+1))
   fi
 
-if [ -s "sample.msi" ]
+if test -s "sample.msi"
   then
-    if [ $(cat "sha256sum_msi.log" | cut -d' ' -f1 | uniq | wc -l) -ne 1 ]
+    if test $(cat "sha256sum_msi.log" | cut -d' ' -f1 | uniq | wc -l) -ne 1
       then
         res=1
         cat "sha256sum_msi.log" >> "results.log"
@@ -51,7 +51,7 @@ if [ -s "sample.msi" ]
     skip=$(($skip+1))
   fi
 
-if [ $skip -lt 3 ]
+if test $skip -lt 3
   then
     test_result "$res" "$test_name"
   else
diff --git a/tests/recipes/07_sign_timestamp b/tests/recipes/07_sign_timestamp
index d5a0c66..ed72808 100644
--- a/tests/recipes/07_sign_timestamp
+++ b/tests/recipes/07_sign_timestamp
@@ -7,7 +7,7 @@ script_path=$(pwd)
 # PE file
 test_name="071. Sign a PE file with Authenticode timestamping"
 printf "\n%s\n" "$test_name"
-if [ -s "test.exe" ] && ! grep -q "no libcurl available" "results.log"
+if test -s "test.exe" && ! grep -q "no libcurl available" "results.log"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
@@ -24,7 +24,7 @@ if [ -s "test.exe" ] && ! grep -q "no libcurl available" "results.log"
 # CAB file
 test_name="072. Sign a CAB file with Authenticode timestamping"
 printf "\n%s\n" "$test_name"
-if [ -s "test.ex_" ] && ! grep -q "no libcurl available" "results.log"
+if test -s "test.ex_" && ! grep -q "no libcurl available" "results.log"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
@@ -41,7 +41,7 @@ if [ -s "test.ex_" ] && ! grep -q "no libcurl available" "results.log"
 # MSI file
 test_name="073. Sign a MSI file with Authenticode timestamping"
 printf "\n%s\n" "$test_name"
-if [ -s "sample.msi" ] && ! grep -q "no libcurl available" "results.log"
+if test -s "sample.msi" && ! grep -q "no libcurl available" "results.log"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
diff --git a/tests/recipes/08_sign_rfc3161 b/tests/recipes/08_sign_rfc3161
index d400209..834a21d 100644
--- a/tests/recipes/08_sign_rfc3161
+++ b/tests/recipes/08_sign_rfc3161
@@ -11,7 +11,7 @@ script_path=$(pwd)
 # PE file
 test_name="081. Sign a PE file with RFC 3161 timestamping"
 printf "\n%s\n" "$test_name"
-if [ -s "test.exe" ] && ! grep -q "no libcurl available" "results.log"
+if test -s "test.exe" && ! grep -q "no libcurl available" "results.log"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
@@ -28,7 +28,7 @@ if [ -s "test.exe" ] && ! grep -q "no libcurl available" "results.log"
 # CAB file
 test_name="082. Sign a CAB file with RFC 3161 timestamping"
 printf "\n%s\n" "$test_name"
-if [ -s "test.ex_" ] && ! grep -q "no libcurl available" "results.log"
+if test -s "test.ex_" && ! grep -q "no libcurl available" "results.log"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
@@ -45,7 +45,7 @@ if [ -s "test.ex_" ] && ! grep -q "no libcurl available" "results.log"
 # MSI file
 test_name="083. Sign a MSI file with RFC 3161 timestamping"
 printf "\n%s\n" "$test_name"
-if [ -s "sample.msi" ] && ! grep -q "no libcurl available" "results.log"
+if test -s "sample.msi" && ! grep -q "no libcurl available" "results.log"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
diff --git a/tests/recipes/09_sign_page_hashes b/tests/recipes/09_sign_page_hashes
index ea83dcf..f69830c 100644
--- a/tests/recipes/09_sign_page_hashes
+++ b/tests/recipes/09_sign_page_hashes
@@ -7,7 +7,7 @@ script_path=$(pwd)
 # PE file
 test_name="091. Generate page hashes for a PE file"
 printf "\n%s\n" "$test_name"
-if [ -s "test.exe" ]
+if test -s "test.exe"
   then
     ../../osslsigncode sign -h sha256 -ph \
         -st "1556668800" \
diff --git a/tests/recipes/10_sign_blob b/tests/recipes/10_sign_blob
index db57e2d..2ab0610 100644
--- a/tests/recipes/10_sign_blob
+++ b/tests/recipes/10_sign_blob
@@ -7,7 +7,7 @@ script_path=$(pwd)
 # PE file
 test_name="101. Sign a PE file with addUnauthenticatedBlob"
 printf "\n%s\n" "$test_name"
-if [ -s "test.exe" ]
+if test -s "test.exe"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
@@ -24,7 +24,7 @@ if [ -s "test.exe" ]
 # CAB file
 test_name="102. Sign a CAB file with addUnauthenticatedBlob"
 printf "\n%s\n" "$test_name"
-if [ -s "test.ex_" ]
+if test -s "test.ex_"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
@@ -41,7 +41,7 @@ if [ -s "test.ex_" ]
 # MSI file
 test_name="103. Sign a MSI file with addUnauthenticatedBlob"
 printf "\n%s\n" "$test_name"
-if [ -s "sample.msi" ]
+if test -s "sample.msi"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
diff --git a/tests/recipes/11_sign_nest b/tests/recipes/11_sign_nest
index edf697c..033861b 100644
--- a/tests/recipes/11_sign_nest
+++ b/tests/recipes/11_sign_nest
@@ -8,7 +8,7 @@ script_path=$(pwd)
 # PE file
 test_name="111. Sign a PE file with the nest flag"
 printf "\n%s\n" "$test_name"
-if [ -s "test.exe" ]
+if test -s "test.exe"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
@@ -32,7 +32,7 @@ if [ -s "test.exe" ]
 # MSI file
 test_name="113. Sign a MSI file with the nest flag"
 printf "\n%s\n" "$test_name"
-if [ -s "sample.msi" ]
+if test -s "sample.msi"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
diff --git a/tests/recipes/12_sign_readpass_pem b/tests/recipes/12_sign_readpass_pem
index ee0513e..556ce0a 100644
--- a/tests/recipes/12_sign_readpass_pem
+++ b/tests/recipes/12_sign_readpass_pem
@@ -7,7 +7,7 @@ script_path=$(pwd)
 # PE file
 test_name="121. Sign a PE file with the PEM key file and the file with a password"
 printf "\n%s\n" "$test_name"
-if [ -s "test.exe" ]
+if test -s "test.exe"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
@@ -24,7 +24,7 @@ if [ -s "test.exe" ]
 # CAB file
 test_name="122. Sign a CAB file with a PEM key file and the file with a password"
 printf "\n%s\n" "$test_name"
-if [ -s "test.ex_" ]
+if test -s "test.ex_"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
@@ -41,7 +41,7 @@ if [ -s "test.ex_" ]
 # MSI file
 test_name="123. Sign a MSI file with a PEM key file and the file with a password"
 printf "\n%s\n" "$test_name"
-if [ -s "sample.msi" ]
+if test -s "sample.msi"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
diff --git a/tests/recipes/13_sign_readpass_pkcs12 b/tests/recipes/13_sign_readpass_pkcs12
index 35f79fd..cc49608 100644
--- a/tests/recipes/13_sign_readpass_pkcs12
+++ b/tests/recipes/13_sign_readpass_pkcs12
@@ -8,7 +8,7 @@ script_path=$(pwd)
 # PE file
 test_name="131. Sign a PE file with a PKCS#12 container and the file with a password"
 printf "\n%s\n" "$test_name"
-if [ -s "test.exe" ]
+if test -s "test.exe"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
@@ -25,7 +25,7 @@ if [ -s "test.exe" ]
 # CAB file
 test_name="132. Sign a CAB file with a PKCS#12 container and the file with a password"
 printf "\n%s\n" "$test_name"
-if [ -s "test.ex_" ]
+if test -s "test.ex_"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
@@ -42,7 +42,7 @@ if [ -s "test.ex_" ]
 # MSI file
 test_name="133. Sign a MSI file with a PKCS#12 container and the file with a password"
 printf "\n%s\n" "$test_name"
-if [ -s "sample.msi" ]
+if test -s "sample.msi"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
diff --git a/tests/recipes/14_sign_descryption b/tests/recipes/14_sign_descryption
index d54b33c..b9f4e59 100644
--- a/tests/recipes/14_sign_descryption
+++ b/tests/recipes/14_sign_descryption
@@ -7,7 +7,7 @@ script_path=$(pwd)
 # PE file
 test_name="141. Sign a PE file with a descryption"
 printf "\n%s\n" "$test_name"
-if [ -s "test.exe" ]
+if test -s "test.exe"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
@@ -24,7 +24,7 @@ if [ -s "test.exe" ]
 # CAB file
 test_name="142. Sign a CAB file with a descryption"
 printf "\n%s\n" "$test_name"
-if [ -s "test.ex_" ]
+if test -s "test.ex_"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
@@ -41,7 +41,7 @@ if [ -s "test.ex_" ]
 # MSI file
 test_name="143. Sign a MSI file with a descryption"
 printf "\n%s\n" "$test_name"
-if [ -s "sample.msi" ]
+if test -s "sample.msi"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
diff --git a/tests/recipes/15_sign_url b/tests/recipes/15_sign_url
index 6feef4a..d659602 100644
--- a/tests/recipes/15_sign_url
+++ b/tests/recipes/15_sign_url
@@ -8,7 +8,7 @@ script_path=$(pwd)
 # PE file
 test_name="151. Sign a PE file with specified URL"
 printf "\n%s\n" "$test_name"
-if [ -s "test.exe" ]
+if test -s "test.exe"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
@@ -25,7 +25,7 @@ if [ -s "test.exe" ]
 # CAB file
 test_name="152. Sign a CAB file with specified URL"
 printf "\n%s\n" "$test_name"
-if [ -s "test.ex_" ]
+if test -s "test.ex_"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
@@ -42,7 +42,7 @@ if [ -s "test.ex_" ]
 # MSI file
 test_name="153. Sign a MSI file with specified URL"
 printf "\n%s\n" "$test_name"
-if [ -s "sample.msi" ]
+if test -s "sample.msi"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
diff --git a/tests/recipes/16_sign_comm b/tests/recipes/16_sign_comm
index 0083c5a..25d74dd 100644
--- a/tests/recipes/16_sign_comm
+++ b/tests/recipes/16_sign_comm
@@ -10,7 +10,7 @@ script_path=$(pwd)
 # PE file
 test_name="161. Sign a PE file with the common purpose set"
 printf "\n%s\n" "$test_name"
-if [ -s "test.exe" ]
+if test -s "test.exe"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
@@ -27,7 +27,7 @@ if [ -s "test.exe" ]
 # CAB file
 test_name="162. Sign a CAB file with the common purpose set"
 printf "\n%s\n" "$test_name"
-if [ -s "test.ex_" ]
+if test -s "test.ex_"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
@@ -44,7 +44,7 @@ if [ -s "test.ex_" ]
 # MSI file
 test_name="163. Sign a MSI file with the common purpose set"
 printf "\n%s\n" "$test_name"
-if [ -s "sample.msi" ]
+if test -s "sample.msi"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
diff --git a/tests/recipes/17_sign_crosscertfile b/tests/recipes/17_sign_crosscertfile
index 65721b0..638d905 100644
--- a/tests/recipes/17_sign_crosscertfile
+++ b/tests/recipes/17_sign_crosscertfile
@@ -9,7 +9,7 @@ script_path=$(pwd)
 # PE file
 test_name="171. Add an additional certificate to the signature block of the PE file"
 printf "\n%s\n" "$test_name"
-if [ -s "test.exe" ]
+if test -s "test.exe"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
@@ -26,7 +26,7 @@ if [ -s "test.exe" ]
 # CAB file
 test_name="172. Add an additional certificate to the signature block of the CAB file"
 printf "\n%s\n" "$test_name"
-if [ -s "test.ex_" ]
+if test -s "test.ex_"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
@@ -43,7 +43,7 @@ if [ -s "test.ex_" ]
 # MSI file
 test_name="173. Add an additional certificate to the signature block of the MSI file"
 printf "\n%s\n" "$test_name"
-if [ -s "sample.msi" ]
+if test -s "sample.msi"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
diff --git a/tests/recipes/21_sign_hash_md5 b/tests/recipes/21_sign_hash_md5
index 5e7cc28..07b2237 100644
--- a/tests/recipes/21_sign_hash_md5
+++ b/tests/recipes/21_sign_hash_md5
@@ -7,7 +7,7 @@ script_path=$(pwd)
 # PE file
 test_name="211. Sign a PE file with MD5 set of cryptographic hash functions"
 printf "\n%s\n" "$test_name"
-if [ -s "test.exe" ]
+if test -s "test.exe"
   then
     ../../osslsigncode sign -h md5 \
         -st "1556668800" \
diff --git a/tests/recipes/22_sign_hash_sha1 b/tests/recipes/22_sign_hash_sha1
index 45db5da..a241a77 100644
--- a/tests/recipes/22_sign_hash_sha1
+++ b/tests/recipes/22_sign_hash_sha1
@@ -7,7 +7,7 @@ script_path=$(pwd)
 # PE file
 test_name="221. Sign a PE file with SHA1 set of cryptographic hash functions"
 printf "\n%s\n" "$test_name"
-if [ -s "test.exe" ]
+if test -s "test.exe"
   then
     ../../osslsigncode sign -h sha1 \
         -st "1556668800" \
diff --git a/tests/recipes/23_sign_hash_sha2 b/tests/recipes/23_sign_hash_sha2
index d14be65..6c77dff 100644
--- a/tests/recipes/23_sign_hash_sha2
+++ b/tests/recipes/23_sign_hash_sha2
@@ -7,7 +7,7 @@ script_path=$(pwd)
 # PE file
 test_name="231. Signing a PE file with SHA1 set of cryptographic hash functions"
 printf "\n%s\n" "$test_name"
-if [ -s "test.exe" ]
+if test -s "test.exe"
   then
     ../../osslsigncode sign -h sha2 \
         -st "1556668800" \
diff --git a/tests/recipes/24_sign_hash_sha384 b/tests/recipes/24_sign_hash_sha384
index 29fca2a..fd7f9c1 100644
--- a/tests/recipes/24_sign_hash_sha384
+++ b/tests/recipes/24_sign_hash_sha384
@@ -7,7 +7,7 @@ script_path=$(pwd)
 # PE file
 test_name="241. Sign a PE file with SHA384 set of cryptographic hash functions"
 printf "\n%s\n" "$test_name"
-if [ -s "test.exe" ]
+if test -s "test.exe"
   then
     ../../osslsigncode sign -h sha384 \
         -st "1556668800" \
diff --git a/tests/recipes/25_sign_hash_sha512 b/tests/recipes/25_sign_hash_sha512
index 9f2efef..35a1485 100644
--- a/tests/recipes/25_sign_hash_sha512
+++ b/tests/recipes/25_sign_hash_sha512
@@ -7,7 +7,7 @@ script_path=$(pwd)
 # PE file
 test_name="251. Sign a PE file with SHA512 set of cryptographic hash functions"
 printf "\n%s\n" "$test_name"
-if [ -s "test.exe" ]
+if test -s "test.exe"
   then
     ../../osslsigncode sign -h sha512 \
         -st "1556668800" \
diff --git a/tests/recipes/31_extract_signature b/tests/recipes/31_extract_signature
index e3ce14e..1b22795 100644
--- a/tests/recipes/31_extract_signature
+++ b/tests/recipes/31_extract_signature
@@ -7,7 +7,7 @@ script_path=$(pwd)
 # PE file
 test_name="311. Extract the signature from the PE file"
 printf "\n%s\n" "$test_name"
-if [ -s "test.exe" ]
+if test -s "test.exe"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
@@ -28,7 +28,7 @@ if [ -s "test.exe" ]
 # MSI file
 test_name="312. Extract the signature from the MSI file"
 printf "\n%s\n" "$test_name"
-if [ -s "sample.msi" ]
+if test -s "sample.msi"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
diff --git a/tests/recipes/32_attach_signature b/tests/recipes/32_attach_signature
index 38d1478..ebf9634 100644
--- a/tests/recipes/32_attach_signature
+++ b/tests/recipes/32_attach_signature
@@ -7,7 +7,7 @@ script_path=$(pwd)
 # PE file
 test_name="321. Attach the signature to the PE file"
 printf "\n%s\n" "$test_name"
-if [ -s "test.exe" ]
+if test -s "test.exe"
   then
     ../../osslsigncode attach-signature -sigin "sign_pe.pem" \
         -CAfile "${script_path}/../certs/CACert.pem" \
@@ -26,7 +26,7 @@ if [ -s "test.exe" ]
 # MSI file
 test_name="322. Attach the signature to the MSI file"
 printf "\n%s\n" "$test_name"
-if [ -s "sample.msi" ]
+if test -s "sample.msi"
   then
     ../../osslsigncode attach-signature -sigin "sign_msi.pem" \
         -CAfile "${script_path}/../certs/CACert.pem" \
diff --git a/tests/recipes/33_remove_signature b/tests/recipes/33_remove_signature
index d6c426f..6183d62 100644
--- a/tests/recipes/33_remove_signature
+++ b/tests/recipes/33_remove_signature
@@ -7,7 +7,7 @@ script_path=$(pwd)
 # PE file
 test_name="331. Remove the signature from the PE file"
 printf "\n%s\n" "$test_name"
-if [ -s "test.exe" ]
+if test -s "test.exe"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
@@ -28,7 +28,7 @@ if [ -s "test.exe" ]
 # MSI file
 test_name="332. Remove the signature from the MSI file"
 printf "\n%s\n" "$test_name"
-if [ -s "sample.msi" ]
+if test -s "sample.msi"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
diff --git a/tests/recipes/35_varia_sha256sum b/tests/recipes/35_varia_sha256sum
index 60cd72b..49d9314 100644
--- a/tests/recipes/35_varia_sha256sum
+++ b/tests/recipes/35_varia_sha256sum
@@ -7,9 +7,9 @@ res=0
 skip=0
 test_name="351. Checking SHA256 message digests for 31x-34x tests"
 printf "\n%s\n" "$test_name"
-if [ -s "test.exe" ]
+if test -s "test.exe"
   then
-    if [ $(cat "sha256sum_exe.log" | cut -d' ' -f1 | uniq | wc -l) -ne 1 ]
+    if test $(cat "sha256sum_exe.log" | cut -d' ' -f1 | uniq | wc -l) -ne 1
       then
         res=1
         cat "sha256sum_exe.log" >> "results.log"
@@ -22,9 +22,9 @@ if [ -s "test.exe" ]
     skip=$(($skip+1))
   fi
 
-if [ -s "sample.msi" ]
+if test -s "sample.msi"
   then
-    if [ $(cat "sha256sum_msi.log" | cut -d' ' -f1 | uniq | wc -l) -ne 1 ]
+    if test $(cat "sha256sum_msi.log" | cut -d' ' -f1 | uniq | wc -l) -ne 1
       then
         res=1
         cat "sha256sum_msi.log" >> "results.log"
@@ -37,7 +37,7 @@ if [ -s "sample.msi" ]
     skip=$(($skip+1))
   fi
 
-if [ $skip -lt 2 ]
+if test $skip -lt 2
   then
     test_result "$res" "$test_name"
   else
diff --git a/tests/recipes/36_add_signature_blob b/tests/recipes/36_add_signature_blob
index 601ca88..c287735 100644
--- a/tests/recipes/36_add_signature_blob
+++ b/tests/recipes/36_add_signature_blob
@@ -7,7 +7,7 @@ script_path=$(pwd)
 # PE file
 test_name="361. Add an unauthenticated blob to the PE file"
 printf "\n%s\n" "$test_name"
-if [ -s "test.exe" ]
+if test -s "test.exe"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
@@ -29,7 +29,7 @@ if [ -s "test.exe" ]
 # MSI file
 test_name="362. Add an unauthenticated blob to the MSI file"
 printf "\n%s\n" "$test_name"
-if [ -s "sample.msi" ]
+if test -s "sample.msi"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
diff --git a/tests/recipes/37_add_signature_timestamp b/tests/recipes/37_add_signature_timestamp
index fffb6e7..547178c 100644
--- a/tests/recipes/37_add_signature_timestamp
+++ b/tests/recipes/37_add_signature_timestamp
@@ -7,7 +7,7 @@ script_path=$(pwd)
 # PE file
 test_name="371. Add an authenticode timestamp to the PE file"
 printf "\n%s\n" "$test_name"
-if [ -s "test.exe" ] && ! grep -q "no libcurl available" "results.log"
+if test -s "test.exe" && ! grep -q "no libcurl available" "results.log"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
@@ -29,7 +29,7 @@ if [ -s "test.exe" ] && ! grep -q "no libcurl available" "results.log"
 # MSI file
 test_name="372. Add an authenticode timestamp to the MSI file"
 printf "\n%s\n" "$test_name"
-if [ -s "sample.msi" ] && ! grep -q "no libcurl available" "results.log"
+if test -s "sample.msi" && ! grep -q "no libcurl available" "results.log"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
diff --git a/tests/recipes/38_add_signature_rfc3161 b/tests/recipes/38_add_signature_rfc3161
index 7372516..a7c48f4 100644
--- a/tests/recipes/38_add_signature_rfc3161
+++ b/tests/recipes/38_add_signature_rfc3161
@@ -7,7 +7,7 @@ script_path=$(pwd)
 # PE file
 test_name="381. Add RFC 3161 timestamp to signed PE file"
 printf "\n%s\n" "$test_name"
-if [ -s "test.exe" ] && ! grep -q "no libcurl available" "results.log"
+if test -s "test.exe" && ! grep -q "no libcurl available" "results.log"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
@@ -29,7 +29,7 @@ if [ -s "test.exe" ] && ! grep -q "no libcurl available" "results.log"
 # MSI file
 test_name="382. Add RFC 3161 timestamp to signed MSI file"
 printf "\n%s\n" "$test_name"
-if [ -s "sample.msi" ] && ! grep -q "no libcurl available" "results.log"
+if test -s "sample.msi" && ! grep -q "no libcurl available" "results.log"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
diff --git a/tests/recipes/40_verify_leaf_hash b/tests/recipes/40_verify_leaf_hash
index 73ec50f..866ea63 100644
--- a/tests/recipes/40_verify_leaf_hash
+++ b/tests/recipes/40_verify_leaf_hash
@@ -7,7 +7,7 @@ script_path=$(pwd)
 # PE file
 test_name="401. Compare the leaf certificate hash against specified SHA256 message digest for the PE file"
 printf "\n%s\n" "$test_name"
-if [ -s "test.exe" ]
+if test -s "test.exe"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
@@ -25,7 +25,7 @@ if [ -s "test.exe" ]
 # MSI file
 test_name="403. Compare the leaf certificate hash against specified SHA256 message digest for the MSI file"
 printf "\n%s\n" "$test_name"
-if [ -s "sample.msi" ]
+if test -s "sample.msi"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
diff --git a/tests/recipes/41_sign_add_msi_dse b/tests/recipes/41_sign_add_msi_dse
index 02c5064..bdb853d 100644
--- a/tests/recipes/41_sign_add_msi_dse
+++ b/tests/recipes/41_sign_add_msi_dse
@@ -17,7 +17,7 @@ script_path=$(pwd)
 # MSI file
 test_name="411. Sign a MSI file with the add-msi-dse option"
 printf "\n%s\n" "$test_name"
-if [ -s "sample.msi" ]
+if test -s "sample.msi"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
diff --git a/tests/recipes/42_sign_jp_low b/tests/recipes/42_sign_jp_low
index aaaa88e..c70f8a3 100644
--- a/tests/recipes/42_sign_jp_low
+++ b/tests/recipes/42_sign_jp_low
@@ -11,7 +11,7 @@ script_path=$(pwd)
 # CAB file
 test_name="421. Sign a CAB file with jp low option"
 printf "\n%s\n" "$test_name"
-if [ -s "test.ex_" ]
+if test -s "test.ex_"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
diff --git a/tests/recipes/45_verify_fake_pe b/tests/recipes/45_verify_fake_pe
index 0e9ce27..6b60c0e 100644
--- a/tests/recipes/45_verify_fake_pe
+++ b/tests/recipes/45_verify_fake_pe
@@ -8,7 +8,7 @@ script_path=$(pwd)
 # PE file
 test_name="451. Verify changed PE file after signing"
 printf "\n%s\n" "$test_name"
-if [ -s "test.exe" ]
+if test -s "test.exe"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
diff --git a/tests/recipes/46_verify_timestamp b/tests/recipes/46_verify_timestamp
index ac9ead3..028f7a7 100644
--- a/tests/recipes/46_verify_timestamp
+++ b/tests/recipes/46_verify_timestamp
@@ -8,7 +8,7 @@ script_path=$(pwd)
 # PE file
 test_name="461. Verify changed PE file after signing with Authenticode timestamping"
 printf "\n%s\n" "$test_name"
-if [ -s "test.exe" ] && ! grep -q "no libcurl available" "results.log"
+if test -s "test.exe" && ! grep -q "no libcurl available" "results.log"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
diff --git a/tests/recipes/47_verify_rfc3161 b/tests/recipes/47_verify_rfc3161
index c5ab544..49a6595 100755
--- a/tests/recipes/47_verify_rfc3161
+++ b/tests/recipes/47_verify_rfc3161
@@ -8,7 +8,7 @@ script_path=$(pwd)
 # PE file
 test_name="471. Verify changed PE file after signing with RFC 3161 timestamping"
 printf "\n%s\n" "$test_name"
-if [ -s "test.exe" ] && ! grep -q "no libcurl available" "results.log"
+if test -s "test.exe" && ! grep -q "no libcurl available" "results.log"
   then
     ../../osslsigncode sign -h sha256 \
         -st "1556668800" \
diff --git a/tests/recipes/51_verify_time b/tests/recipes/51_verify_time
index 252bdd3..35274dd 100644
--- a/tests/recipes/51_verify_time
+++ b/tests/recipes/51_verify_time
@@ -6,7 +6,7 @@
 # PE file
 test_name="511. Verify PE file signature after the cert has been expired"
 printf "\n%s\n" "$test_name"
-if [ -s "test.exe" ]
+if test -s "test.exe"
   then
     TZ=GMT faketime -f '@2019-05-01 00:00:00' /bin/bash -c '
         script_path=$(pwd)
@@ -26,7 +26,7 @@ if [ -s "test.exe" ]
 # MSI file
 test_name="513. Verify MSI file signature after the cert has been expired"
 printf "\n%s\n" "$test_name"
-if [ -s "sample.msi" ]
+if test -s "sample.msi"
   then
     TZ=GMT faketime -f '@2019-05-01 00:00:00' /bin/bash -c '
         script_path=$(pwd)
diff --git a/tests/recipes/52_verify_timestamp b/tests/recipes/52_verify_timestamp
index 0971457..cab4e9b 100644
--- a/tests/recipes/52_verify_timestamp
+++ b/tests/recipes/52_verify_timestamp
@@ -6,7 +6,7 @@
 # PE file
 test_name="521. Verify PE file signature with timestamping after the cert has been expired"
 printf "\n%s\n" "$test_name"
-if [ -s "test.exe" ] && ! grep -q "no libcurl available" "results.log"
+if test -s "test.exe" && ! grep -q "no libcurl available" "results.log"
   then
     TZ=GMT faketime -f '@2019-05-01 00:00:00' /bin/bash -c '
         script_path=$(pwd)
@@ -27,7 +27,7 @@ if [ -s "test.exe" ] && ! grep -q "no libcurl available" "results.log"
 # MSI file
 test_name="523. Verify MSI file signature with timestamping after the cert has been expired"
 printf "\n%s\n" "$test_name"
-if [ -s "sample.msi" ] && ! grep -q "no libcurl available" "results.log"
+if test -s "sample.msi" && ! grep -q "no libcurl available" "results.log"
   then
     TZ=GMT faketime -f '@2019-05-01 00:00:00' /bin/bash -c '
         script_path=$(pwd)
diff --git a/tests/recipes/53_verify_rfc3161 b/tests/recipes/53_verify_rfc3161
index 51226ba..403a9b7 100644
--- a/tests/recipes/53_verify_rfc3161
+++ b/tests/recipes/53_verify_rfc3161
@@ -6,7 +6,7 @@
 # PE file
 test_name="531. Verify PE file signature with RFC3161 after the cert has been expired"
 printf "\n%s\n" "$test_name"
-if [ -s "test.exe" ] && ! grep -q "no libcurl available" "results.log"
+if test -s "test.exe" && ! grep -q "no libcurl available" "results.log"
   then
     TZ=GMT faketime -f '@2019-05-01 00:00:00' /bin/bash -c '
         script_path=$(pwd)
@@ -27,7 +27,7 @@ if [ -s "test.exe" ] && ! grep -q "no libcurl available" "results.log"
 # MSI file
 test_name="533. Verify MSI file signature with RFC3161 after the cert has been expired"
 printf "\n%s\n" "$test_name"
-if [ -s "sample.msi" ] && ! grep -q "no libcurl available" "results.log"
+if test -s "sample.msi" && ! grep -q "no libcurl available" "results.log"
   then
     TZ=GMT faketime -f '@2019-05-01 00:00:00' /bin/bash -c '
         script_path=$(pwd)
diff --git a/tests/recipes/54_verify_expired b/tests/recipes/54_verify_expired
index 2acff2f..9e987e5 100644
--- a/tests/recipes/54_verify_expired
+++ b/tests/recipes/54_verify_expired
@@ -6,7 +6,7 @@
 # PE file
 test_name="541. Verify PE file signed with the expired cert"
 printf "\n%s\n" "$test_name"
-if [ -s "test.exe" ] && ! grep -q "no libcurl available" "results.log"
+if test -s "test.exe" && ! grep -q "no libcurl available" "results.log"
   then
     TZ=GMT faketime -f '@2019-05-01 00:00:00' /bin/bash -c '
         script_path=$(pwd)
@@ -27,7 +27,7 @@ if [ -s "test.exe" ] && ! grep -q "no libcurl available" "results.log"
 # MSI file
 test_name="543. Verify MSI file signed with the expired cert"
 printf "\n%s\n" "$test_name"
-if [ -s "sample.msi" ] && ! grep -q "no libcurl available" "results.log"
+if test -s "sample.msi" && ! grep -q "no libcurl available" "results.log"
   then
     TZ=GMT faketime -f '@2019-05-01 00:00:00' /bin/bash -c '
         script_path=$(pwd)
diff --git a/tests/recipes/55_verify_revoked b/tests/recipes/55_verify_revoked
index 830eb23..b14c488 100644
--- a/tests/recipes/55_verify_revoked
+++ b/tests/recipes/55_verify_revoked
@@ -6,7 +6,7 @@
 # PE file
 test_name="551. Verify PE file signed with the revoked cert"
 printf "\n%s\n" "$test_name"
-if [ -s "test.exe" ] && ! grep -q "no libcurl available" "results.log"
+if test -s "test.exe" && ! grep -q "no libcurl available" "results.log"
   then
     TZ=GMT faketime -f '@2019-05-01 00:00:00' /bin/bash -c '
         script_path=$(pwd)
@@ -27,7 +27,7 @@ if [ -s "test.exe" ] && ! grep -q "no libcurl available" "results.log"
 # MSI file
 test_name="553. Verify MSI file signed with the revoked cert"
 printf "\n%s\n" "$test_name"
-if [ -s "sample.msi" ] && ! grep -q "no libcurl available" "results.log"
+if test -s "sample.msi" && ! grep -q "no libcurl available" "results.log"
   then
     TZ=GMT faketime -f '@2019-05-01 00:00:00' /bin/bash -c '
         script_path=$(pwd)
diff --git a/tests/test_library b/tests/test_library
index 6e9b3ae..fe12012 100755
--- a/tests/test_library
+++ b/tests/test_library
@@ -11,7 +11,7 @@ test_result() {
 
   local result=0
 
-  if [ "$1" -eq 0 ]
+  if test "$1" -eq 0
     then
       printf "%s\n" "Test succeeded"
     else
@@ -40,8 +40,8 @@ modify_blob() {
       -CRLfile "${script_path}/../certs/CACertCRL.pem" \
       -in "test_$1_changed.$2" 2>> "verify.log" 1>&2
   result=$?
-  if [ "$result" -ne 0 ] || \
-      [ $(grep -e "Calculated DigitalSignature" -e "Calculated message digest" "verify.log" | uniq | wc -l) -ne 1 ]
+  if test "$result" -ne 0 \
+      -o $(grep -e "Calculated DigitalSignature" -e "Calculated message digest" "verify.log" | uniq | wc -l) -ne 1
     then
       printf "Failed: verify error or non-unique message digests found\n" 2>> "verify.log" 1>&2
       result=1
@@ -61,7 +61,7 @@ search_pattern() {
 
   local result=0
 
-  if [ "$3" = "ASCII" ]
+  if test "$3" = "ASCII"
     then
       hex_pattern=$(echo -n "$4" | xxd -p)
     else
@@ -72,9 +72,9 @@ search_pattern() {
     then
       result=1
       printf "Failed: $4 not found\n"
-    elif [ "$5" = "MODIFY" ]
+    elif test "$5" = "MODIFY"
       then
-        if [ "$2" != "ex_" ]
+        if test "$2" != "ex_"
          then
            modify_blob "$1" "$2" "$4"
            result=$?
@@ -99,9 +99,9 @@ verify_signature() {
 
   local result=0
   printf "" > "verify.log"
-  if [ "$1" -eq 0 ]
+  if test "$1" -eq 0
     then
-      if [ "$3" != "ex_" ]
+      if test "$3" != "ex_"
         then
           cp "test_$2.$3" "test_tmp.tmp"
           TZ=GMT faketime -f "$5" /bin/bash -c '
@@ -116,25 +116,25 @@ verify_signature() {
         else
            printf "VERIFY is not supported for CAB files\n"
         fi
-      if [ "$result" -eq 0 ] && [ "$7" != "UNUSED_PATTERN" ] && [ "$8" != "UNUSED_PATTERN" ]
+      if test "$result" -eq 0 -a "$7" != "UNUSED_PATTERN" -a "$8" != "UNUSED_PATTERN"
         then
           search_pattern "$2" "$3" "$7" "$8" "$9"
           result=$?
         fi
-      if [ "$6" = "sha256sum" ]
+      if test "$6" = "sha256sum"
         then
-          if [ -s "test_$2_signed.$3" ]
+          if test -s "test_$2_signed.$3"
             then
               sha256sum "test_$2_signed.$3" 2>> "sha256sum_$3.log" 1>&2
             else
               sha256sum "test_$2.$3" 2>> "sha256sum_$3.log" 1>&2
             fi
         fi
-      if [ "$4" = "success" ] && [ "$result" -eq 0 ]
+      if test "$4" = "success" -a "$result" -eq 0
         then
           rm -f "test_$2.$3" "test_$2_signed.$3" "test_$2_modifed.$3" "test_$2_changed.$3"
           result=0
-        elif [ "$4" = "fail" ] && [ "$result" -eq 1 ]
+        elif test "$4" = "fail" -a "$result" -eq 1
           then
             rm -f "test_$2.$3" "test_$2_signed.$3" "test_$2_modifed.$3" "test_$2_changed.$3"
             cat "verify.log" >> "results.log"
@@ -157,9 +157,9 @@ verify_leaf_hash() {
 
   local result=0
   printf "" > "verify.log"
-  if [ "$1" -eq 0 ]
+  if test "$1" -eq 0
     then
-      if [ "$3" != "ex_" ]
+      if test "$3" != "ex_"
         then
           cp "test_$2.$3" "test_tmp.tmp"
           TZ=GMT faketime -f "$4" /bin/bash -c '
@@ -175,7 +175,7 @@ verify_leaf_hash() {
         else
            printf "VERIFY is not supported for CAB files\n"
         fi
-      if [ "$result" -eq 0 ]
+      if test "$result" -eq 0
         then
           rm -f "test_$2.$3"
         else
diff --git a/tests/testall.sh b/tests/testall.sh
index 6cb25ee..81aafde 100755
--- a/tests/testall.sh
+++ b/tests/testall.sh
@@ -19,7 +19,7 @@ make_tests() {
       /bin/sh $plik 3>&1 2>> "results.log" 1>&2
     done
     count=$(grep -c "Test succeeded" "results.log")
-  if [ $count -ne 0 ]
+  if test $count -ne 0
     then
       skip=$(grep -c "Test skipped" "results.log")
       fail=$(grep -c "Test failed" "results.log")
@@ -38,9 +38,9 @@ date > "results.log"
 ../../osslsigncode -v >> "results.log" 2>/dev/null
 
 cd ${certs_path}
-if [ -s CACert.pem ] && [ -s crosscert.pem ] && [ -s expired.pem ] && [ -s cert.pem ] && \
-    [ -s CACertCRL.pem ] && [ -s revoked.pem ] && [ -s key.pem ] && [ -s keyp.pem ] && \
-    [ -s key.der ] && [ -s cert.der ] && [ -s cert.spc ] && [ -s cert.p12 ]
+if test -s CACert.pem -a -s crosscert.pem -a -s expired.pem -a -s cert.pem \
+    -a -s CACertCRL.pem -a -s revoked.pem -a -s key.pem -a -s keyp.pem \
+    -a -s key.der -a -s cert.der -a -s cert.spc -a -s cert.p12
   then
     printf "%s\n" "keys & certificates path: ${certs_path}"
   else
@@ -49,16 +49,16 @@ if [ -s CACert.pem ] && [ -s crosscert.pem ] && [ -s expired.pem ] && [ -s cert.
   fi
 cd "${result_path}"
 
-if [ "$result" -ne 0 ]
+if test "$result" -ne 0
   then
     exit $result
   fi
 
 # PE and CAB files support
-if [ -n "$(command -v x86_64-w64-mingw32-gcc)" ]
+if test -n "$(command -v x86_64-w64-mingw32-gcc)"
   then
     x86_64-w64-mingw32-gcc "../myapp.c" -o "test.exe" 2>> "results.log" 1>&2
-    if [ -n "$(command -v gcab)" ]
+    if test -n "$(command -v gcab)"
       then
         gcab -c "test.ex_" "test.exe" 2>> "results.log" 1>&2
       else
@@ -75,7 +75,7 @@ if grep -q "no libgsf available" "results.log"
   then
     printf "%s\n" "signing MSI files requires libgsf/libgsf-devel packages and reconfiguration osslsigncode"
   else
-    if [ -n "$(command -v wixl)" ]
+    if test -n "$(command -v wixl)"
       then
         touch FoobarAppl10.exe
         cp "../sample.wxs" "sample.wxs" 2>> "results.log" 1>&2
@@ -93,9 +93,9 @@ if grep -q "no libcurl available" "results.log"
   fi
 
 # Tests requirements
-if [ -n "$(command -v faketime)" ]
+if test -n "$(command -v faketime)"
   then
-    if [ -n "$(command -v xxd)" ]
+    if test -n "$(command -v xxd)"
       then
         make_tests
         result=$?