3 files changed, 130 insertions, 0 deletions

diff --git a/tests/runner.c b/tests/runner.c
index 1b6deb1..c9385f0 100644
--- a/tests/runner.c
+++ b/tests/runner.c
@@ -18,6 +18,7 @@ static const struct module modules[] = {{"scan_urlencoded_query", test_scan_urle
                                         {"ot_iovec", test_iovec},
                                         {"ot_vector", test_vector},
                                         {"ot_random", test_random},
+                                        {"ot_hex", test_hex},
                                         {NULL, NULL}};
 
 /* Run every module, or only those whose name contains argv[1] */
diff --git a/tests/t_hex.c b/tests/t_hex.c
new file mode 100644
index 0000000..7cce8ac
--- /dev/null
+++ b/tests/t_hex.c
@@ -0,0 +1,128 @@
+/* This software was written by Dirk Engling <erdgeist@erdgeist.org>
+   It is considered beerware. Prost. Skol. Cheers or whatever.
+
+   $id$ */
+
+/* System */
+#include <stdint.h>
+#include <string.h>
+
+/* Opentracker */
+#include "ot_hex.h"
+#include "test.h"
+
+static const uint8_t sample[20] = {0x00, 0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 0xff, 0x10, 0x20, 0x30, 0x40, 0x50, 0x60, 0x70, 0x80, 0x90, 0xa0};
+
+static void case_encode(void) {
+  char dest[64];
+
+  test_case("a hash encodes to forty upper case digits and a terminator");
+  memset(dest, 0x7f, sizeof(dest));
+  CHECK_PTR(hex_fromhash(dest, sample), dest);
+  CHECK_STR(dest, "000123456789ABCDEFFF10203040506070809" "0A0");
+  CHECK_INT(strlen(dest), 40);
+  CHECK_INT((unsigned char)dest[41], 0x7f);
+}
+
+static void case_decode(void) {
+  ot_hash hash;
+
+  test_case("forty digits decode back to the hash");
+  CHECK(hex_tohash(hash, "000123456789ABCDEFFF10203040506070809" "0A0"));
+  CHECK_MEM(hash, sample, sizeof(sample));
+}
+
+static void case_round_trip(void) {
+  ot_hash hash;
+  char    text[64];
+  size_t  i;
+
+  test_case("encode and decode are inverses over every byte value");
+  for (i = 0; i < 256; ++i) {
+    uint8_t probe[20];
+    memset(probe, (uint8_t)i, sizeof(probe));
+    hex_fromhash(text, probe);
+    if (!hex_tohash(hash, text) || memcmp(hash, probe, sizeof(probe))) {
+      test_failf(__FILE__, __LINE__, "round trip failed for byte value %zu", i);
+      return;
+    }
+  }
+  ++test_checks;
+}
+
+static void case_decode_is_case_insensitive(void) {
+  ot_hash upper, lower;
+
+  test_case("lower case digits decode the same as upper case");
+  CHECK(hex_tohash(upper, "ABCDEF0123456789ABCDEF0123456789ABCDEF01"));
+  CHECK(hex_tohash(lower, "abcdef0123456789abcdef0123456789abcdef01"));
+  CHECK_MEM(lower, upper, sizeof(ot_hash));
+}
+
+static void case_rejects_non_digits(void) {
+  ot_hash hash;
+
+  test_case("a non hex character anywhere rejects the whole string");
+  CHECK_INT(hex_tohash(hash, "g00123456789ABCDEFFF102030405060708090A0"), 0);
+  CHECK_INT(hex_tohash(hash, "000123456789ABCDEFFF102030405060708090Ag"), 0);
+  CHECK_INT(hex_tohash(hash, "000123456789ABCDEF:F102030405060708090A"), 0);
+}
+
+static void case_rejects_short_input(void) {
+  ot_hash hash;
+
+  test_case("a string shorter than forty digits is rejected");
+  CHECK_INT(hex_tohash(hash, ""), 0);
+  CHECK_INT(hex_tohash(hash, "00"), 0);
+  CHECK_INT(hex_tohash(hash, "000123456789ABCDEFFF102030405060708090A"), 0);
+}
+
+static void case_leaves_hash_untouched_on_failure(void) {
+  ot_hash hash;
+
+  test_case("a rejected string leaves the destination untouched");
+  memset(hash, 0x5a, sizeof(hash));
+  CHECK_INT(hex_tohash(hash, "000123456789ABCDEFFF10203040506070809XX0"), 0);
+  CHECK_MEM(hash, "\x5a\x5a\x5a\x5a\x5a\x5a\x5a\x5a\x5a\x5a\x5a\x5a\x5a\x5a\x5a\x5a\x5a\x5a\x5a\x5a", sizeof(hash));
+}
+
+static void case_stops_at_the_terminator(void) {
+  /* The saved state parser hands this whole buffers that may end early. The
+     decoder must not read past the zero that stopped it. */
+  char    guarded[8];
+  ot_hash hash;
+
+  test_case("decoding stops at a terminator rather than running past it");
+  memcpy(guarded, "0012", 4);
+  guarded[4] = 0;
+  memset(guarded + 5, 'f', 3);
+  CHECK_INT(hex_tohash(hash, guarded), 0);
+}
+
+static void case_isdigit(void) {
+  test_case("hex_isdigit accepts exactly the hex digits");
+  CHECK(hex_isdigit('0'));
+  CHECK(hex_isdigit('9'));
+  CHECK(hex_isdigit('a'));
+  CHECK(hex_isdigit('f'));
+  CHECK(hex_isdigit('A'));
+  CHECK(hex_isdigit('F'));
+  CHECK_INT(hex_isdigit('g'), 0);
+  CHECK_INT(hex_isdigit('G'), 0);
+  CHECK_INT(hex_isdigit(':'), 0);
+  CHECK_INT(hex_isdigit('\n'), 0);
+  CHECK_INT(hex_isdigit(0), 0);
+  CHECK_INT(hex_isdigit(0x80), 0);
+}
+
+void test_hex(void) {
+  case_encode();
+  case_decode();
+  case_round_trip();
+  case_decode_is_case_insensitive();
+  case_rejects_non_digits();
+  case_rejects_short_input();
+  case_leaves_hash_untouched_on_failure();
+  case_stops_at_the_terminator();
+  case_isdigit();
+}
diff --git a/tests/test.h b/tests/test.h
index 19acb2f..6af0083 100644
--- a/tests/test.h
+++ b/tests/test.h
@@ -80,5 +80,6 @@ void test_scan_urlencoded_query(void);
 void test_iovec(void);
 void test_vector(void);
 void test_random(void);
+void test_hex(void);
 
 #endif