diff --git a/Makefile b/Makefile
index d3dbef1..26bab4b 100644
--- a/Makefile
+++ b/Makefile
@@ -30,8 +30,8 @@ all: otpcli
clean:
rm -f otpcli ${OBJ} ${P}-${V}.tgz
-test: all run-tests.sh
- sh ./run-tests.sh
+test: all
+ prove
dist: clean
pax -w -s ',^,$P-$V/,' ${DIST} | gzip >$P-$V.tgz
diff --git a/run-tests.sh b/run-tests.sh
deleted file mode 100644
index db49a80..0000000
--- a/run-tests.sh
+++ /dev/null
@@ -1,121 +0,0 @@
-#!/bin/sh
-
-# otpcli - command-line interface for HOTP and TOTP
-#
-# Written in 2020 by Lucas
-#
-# To the extent possible under law, the author(s) have dedicated all
-# copyright and related and neighboring rights to this software to the
-# public domain worldwide. This software is distributed without any
-# warranty.
-#
-# You should have received a copy of the CC0 Public Domain Dedication
-# along with this software. If not, see
-# .
-
-_test_rc=0
-_test_nr=0
-
-case_eq()
-{
- _test_nr=$((_test_nr + 1))
-
- expected=$1
- shift
-
- got=$("$@")
- if [ "$got" != "$expected" ]; then
- printf "test %u: expected %s, got %s\n" \
- "$_test_nr" "$expected" "$got" >&2
- _test_rc=1
- fi
-}
-
-case_stdin_eq()
-{
- _test_nr=$((_test_nr + 1))
-
- expected=$1
- input=$2
- shift 2
-
- got=$(printf "%s\n" "$input" | "$@")
- if [ "$got" != "$expected" ]; then
- printf "test %u: expected %s, got %s\n" \
- "$_test_nr" "$expected" "$got" >&2
- _test_rc=1
- fi
-}
-
-b="GEZDGNBVGY3TQOJQ"
-HOTP_SECRET=$b$b
-TOTP_SECRET=$b$b
-TOTP_SHA256_SECRET=$b$b$b"GEZA"
-TOTP_SHA512_SECRET=$b$b$b$b$b$b"GEZDGNA"
-
-case_eq 755224 ./otpcli -H 0 "$HOTP_SECRET"
-case_eq 287082 ./otpcli -H 1 "$HOTP_SECRET"
-case_eq 359152 ./otpcli -H 2 "$HOTP_SECRET"
-case_eq 969429 ./otpcli -H 3 "$HOTP_SECRET"
-case_eq 338314 ./otpcli -H 4 "$HOTP_SECRET"
-case_eq 254676 ./otpcli -H 5 "$HOTP_SECRET"
-case_eq 287922 ./otpcli -H 6 "$HOTP_SECRET"
-case_eq 162583 ./otpcli -H 7 "$HOTP_SECRET"
-case_eq 399871 ./otpcli -H 8 "$HOTP_SECRET"
-case_eq 520489 ./otpcli -H 9 "$HOTP_SECRET"
-
-case_stdin_eq 755224 "$HOTP_SECRET" ./otpcli -H 0
-case_stdin_eq 287082 "$HOTP_SECRET" ./otpcli -H 1
-case_stdin_eq 359152 "$HOTP_SECRET" ./otpcli -H 2
-case_stdin_eq 969429 "$HOTP_SECRET" ./otpcli -H 3
-case_stdin_eq 338314 "$HOTP_SECRET" ./otpcli -H 4
-case_stdin_eq 254676 "$HOTP_SECRET" ./otpcli -H 5
-case_stdin_eq 287922 "$HOTP_SECRET" ./otpcli -H 6
-case_stdin_eq 162583 "$HOTP_SECRET" ./otpcli -H 7
-case_stdin_eq 399871 "$HOTP_SECRET" ./otpcli -H 8
-case_stdin_eq 520489 "$HOTP_SECRET" ./otpcli -H 9
-
-case_eq 94287082 ./otpcli -d 8 -a sha1 -T 59 "$TOTP_SECRET"
-case_eq 46119246 ./otpcli -d 8 -a sha256 -T 59 "$TOTP_SHA256_SECRET"
-case_eq 90693936 ./otpcli -d 8 -a sha512 -T 59 "$TOTP_SHA512_SECRET"
-case_eq 07081804 ./otpcli -d 8 -a sha1 -T 1111111109 "$TOTP_SECRET"
-case_eq 68084774 ./otpcli -d 8 -a sha256 -T 1111111109 "$TOTP_SHA256_SECRET"
-case_eq 25091201 ./otpcli -d 8 -a sha512 -T 1111111109 "$TOTP_SHA512_SECRET"
-case_eq 14050471 ./otpcli -d 8 -a sha1 -T 1111111111 "$TOTP_SECRET"
-case_eq 67062674 ./otpcli -d 8 -a sha256 -T 1111111111 "$TOTP_SHA256_SECRET"
-case_eq 99943326 ./otpcli -d 8 -a sha512 -T 1111111111 "$TOTP_SHA512_SECRET"
-case_eq 89005924 ./otpcli -d 8 -a sha1 -T 1234567890 "$TOTP_SECRET"
-case_eq 91819424 ./otpcli -d 8 -a sha256 -T 1234567890 "$TOTP_SHA256_SECRET"
-case_eq 93441116 ./otpcli -d 8 -a sha512 -T 1234567890 "$TOTP_SHA512_SECRET"
-case_eq 69279037 ./otpcli -d 8 -a sha1 -T 2000000000 "$TOTP_SECRET"
-case_eq 90698825 ./otpcli -d 8 -a sha256 -T 2000000000 "$TOTP_SHA256_SECRET"
-case_eq 38618901 ./otpcli -d 8 -a sha512 -T 2000000000 "$TOTP_SHA512_SECRET"
-case_eq 65353130 ./otpcli -d 8 -a sha1 -T 20000000000 "$TOTP_SECRET"
-case_eq 77737706 ./otpcli -d 8 -a sha256 -T 20000000000 "$TOTP_SHA256_SECRET"
-case_eq 47863826 ./otpcli -d 8 -a sha512 -T 20000000000 "$TOTP_SHA512_SECRET"
-
-case_stdin_eq 94287082 "$TOTP_SECRET" ./otpcli -d 8 -a sha1 -T 59
-case_stdin_eq 46119246 "$TOTP_SHA256_SECRET" ./otpcli -d 8 -a sha256 -T 59
-case_stdin_eq 90693936 "$TOTP_SHA512_SECRET" ./otpcli -d 8 -a sha512 -T 59
-case_stdin_eq 07081804 "$TOTP_SECRET" ./otpcli -d 8 -a sha1 -T 1111111109
-case_stdin_eq 68084774 "$TOTP_SHA256_SECRET" ./otpcli -d 8 -a sha256 -T 1111111109
-case_stdin_eq 25091201 "$TOTP_SHA512_SECRET" ./otpcli -d 8 -a sha512 -T 1111111109
-case_stdin_eq 14050471 "$TOTP_SECRET" ./otpcli -d 8 -a sha1 -T 1111111111
-case_stdin_eq 67062674 "$TOTP_SHA256_SECRET" ./otpcli -d 8 -a sha256 -T 1111111111
-case_stdin_eq 99943326 "$TOTP_SHA512_SECRET" ./otpcli -d 8 -a sha512 -T 1111111111
-case_stdin_eq 89005924 "$TOTP_SECRET" ./otpcli -d 8 -a sha1 -T 1234567890
-case_stdin_eq 91819424 "$TOTP_SHA256_SECRET" ./otpcli -d 8 -a sha256 -T 1234567890
-case_stdin_eq 93441116 "$TOTP_SHA512_SECRET" ./otpcli -d 8 -a sha512 -T 1234567890
-case_stdin_eq 69279037 "$TOTP_SECRET" ./otpcli -d 8 -a sha1 -T 2000000000
-case_stdin_eq 90698825 "$TOTP_SHA256_SECRET" ./otpcli -d 8 -a sha256 -T 2000000000
-case_stdin_eq 38618901 "$TOTP_SHA512_SECRET" ./otpcli -d 8 -a sha512 -T 2000000000
-case_stdin_eq 65353130 "$TOTP_SECRET" ./otpcli -d 8 -a sha1 -T 20000000000
-case_stdin_eq 77737706 "$TOTP_SHA256_SECRET" ./otpcli -d 8 -a sha256 -T 20000000000
-case_stdin_eq 47863826 "$TOTP_SHA512_SECRET" ./otpcli -d 8 -a sha512 -T 20000000000
-
-if [ $_test_rc -eq 0 ]; then
- printf "All %u tests completed successfully!\n" "$_test_nr" >&2
-else
- printf "Some tests failed\n" >&2
-fi
-exit $_test_rc
diff --git a/t/0000-RFC-4226-Test-Vectors.t b/t/0000-RFC-4226-Test-Vectors.t
new file mode 100644
index 0000000..9ddb5f2
--- /dev/null
+++ b/t/0000-RFC-4226-Test-Vectors.t
@@ -0,0 +1,24 @@
+#!/bin/sh
+[ -n "${0%/*}" ] && cd "${0%/*}"
+. ./lib.sh
+
+if [ ! -x ../otpcli ]; then
+ plan 0 "skip: build otpcli first"
+ exit 1
+fi
+
+# base32("12345678901234567890")
+key=GEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQ
+
+plan 10
+
+check "counter 0" 755224 ../otpcli -H 0 "$key"
+check "counter 1" 287082 ../otpcli -H 1 "$key"
+check "counter 2" 359152 ../otpcli -H 2 "$key"
+check "counter 3" 969429 ../otpcli -H 3 "$key"
+check "counter 4" 338314 ../otpcli -H 4 "$key"
+check "counter 5" 254676 ../otpcli -H 5 "$key"
+check "counter 6" 287922 ../otpcli -H 6 "$key"
+check "counter 7" 162583 ../otpcli -H 7 "$key"
+check "counter 8" 399871 ../otpcli -H 8 "$key"
+check "counter 9" 520489 ../otpcli -H 9 "$key"
diff --git a/t/0001-RFC-6238-SHA-1-Test-Vectors.t b/t/0001-RFC-6238-SHA-1-Test-Vectors.t
new file mode 100644
index 0000000..db69288
--- /dev/null
+++ b/t/0001-RFC-6238-SHA-1-Test-Vectors.t
@@ -0,0 +1,20 @@
+#!/bin/sh
+[ -n "${0%/*}" ] && cd "${0%/*}"
+. ./lib.sh
+
+if [ ! -x ../otpcli ]; then
+ plan 0 "skip: build otpcli first"
+ exit 1
+fi
+
+plan 6
+
+# base32("12345678901234567890")
+key=GEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQ
+
+check "time 59" 94287082 ../otpcli -d 8 -a sha1 -T 59 "$key"
+check "time 1111111109" 07081804 ../otpcli -d 8 -a sha1 -T 1111111109 "$key"
+check "time 1111111111" 14050471 ../otpcli -d 8 -a sha1 -T 1111111111 "$key"
+check "time 1234567890" 89005924 ../otpcli -d 8 -a sha1 -T 1234567890 "$key"
+check "time 2000000000" 69279037 ../otpcli -d 8 -a sha1 -T 2000000000 "$key"
+check "time 20000000000" 65353130 ../otpcli -d 8 -a sha1 -T 20000000000 "$key"
diff --git a/t/0002-RFC-6238-SHA-256-Test-Vectors.t b/t/0002-RFC-6238-SHA-256-Test-Vectors.t
new file mode 100644
index 0000000..d77a94d
--- /dev/null
+++ b/t/0002-RFC-6238-SHA-256-Test-Vectors.t
@@ -0,0 +1,20 @@
+#!/bin/sh
+[ -n "${0%/*}" ] && cd "${0%/*}"
+. ./lib.sh
+
+if [ ! -x ../otpcli ]; then
+ plan 0 "skip: build otpcli first"
+ exit 1
+fi
+
+plan 6
+
+# base32("12345678901234567890123456789012")
+key=GEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZA
+
+check "time 59" 46119246 ../otpcli -d 8 -a sha256 -T 59 "$key"
+check "time 1111111109" 68084774 ../otpcli -d 8 -a sha256 -T 1111111109 "$key"
+check "time 1111111111" 67062674 ../otpcli -d 8 -a sha256 -T 1111111111 "$key"
+check "time 1234567890" 91819424 ../otpcli -d 8 -a sha256 -T 1234567890 "$key"
+check "time 2000000000" 90698825 ../otpcli -d 8 -a sha256 -T 2000000000 "$key"
+check "time 20000000000" 77737706 ../otpcli -d 8 -a sha256 -T 20000000000 "$key"
diff --git a/t/0003-RFC-6238-SHA-512-Test-Vectors.t b/t/0003-RFC-6238-SHA-512-Test-Vectors.t
new file mode 100644
index 0000000..9e657a6
--- /dev/null
+++ b/t/0003-RFC-6238-SHA-512-Test-Vectors.t
@@ -0,0 +1,20 @@
+#!/bin/sh
+[ -n "${0%/*}" ] && cd "${0%/*}"
+. ./lib.sh
+
+if [ ! -x ../otpcli ]; then
+ plan 0 "skip: build otpcli first"
+ exit 1
+fi
+
+plan 6
+
+# base32("1234567890123456789012345678901234567890123456789012345678901234")
+key=GEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQGEZDGNA
+
+check "time 59" 90693936 ../otpcli -d 8 -a sha512 -T 59 "$key"
+check "time 1111111109" 25091201 ../otpcli -d 8 -a sha512 -T 1111111109 "$key"
+check "time 1111111111" 99943326 ../otpcli -d 8 -a sha512 -T 1111111111 "$key"
+check "time 1234567890" 93441116 ../otpcli -d 8 -a sha512 -T 1234567890 "$key"
+check "time 2000000000" 38618901 ../otpcli -d 8 -a sha512 -T 2000000000 "$key"
+check "time 20000000000" 47863826 ../otpcli -d 8 -a sha512 -T 20000000000 "$key"
diff --git a/t/lib.sh b/t/lib.sh
new file mode 100644
index 0000000..8f2b034
--- /dev/null
+++ b/t/lib.sh
@@ -0,0 +1,52 @@
+#!/bin/sh
+# otpcli - command-line interface for HOTP and TOTP
+#
+# Written in 2021 by Lucas
+#
+# To the extent possible under law, the author(s) have dedicated all
+# copyright and related and neighboring rights to this software to the
+# public domain worldwide. This software is distributed without any
+# warranty.
+#
+# You should have received a copy of the CC0 Public Domain Dedication
+# along with this software. If not, see
+# .
+
+# Produces TAP (Test Anything Protocol) output
+
+# plan number_of_tests [directive]
+plan()
+{
+ _n=$1
+ shift
+
+ if [ -n "$*" ]; then
+ printf "1..%u # %s\n" "$_n" "$*"
+ else
+ printf "1..%u\n" "$_n"
+ fi
+
+ _counter=1
+}
+
+# check description expected command [args...]
+check()
+{
+ _description=$1 _expected=$2
+ shift 2
+ _got=$("${@:-:}")
+
+ _rc=0
+ if [ "$_got" != "$_expected" ]; then
+ printf "not ok %u - %s\n" "$_counter" "$_description"
+ printf " # Failed test at %s.\n" "$0"
+ printf " # got: '%s'\n" "$_got"
+ printf " # expected: '%s'\n" "$_expected"
+ _rc=1
+ else
+ printf "ok %u - %s\n" "$_counter" "$_description"
+ fi
+
+ _counter=$(($_counter + 1))
+ return $_rc
+}