bitrev_test: don't omit last byte from test result check

The osmo_hexdump of the output in sh_chk() omitted the last byte of the
returned bytes from the osmo_nibble_shift_*() functions.

Determine the number of bytes from nibbles divided by two plus one for any odd
nibble number. Output this number of bytes of output data.

Memset the output buffer to get well-defined bytes for unwritten places.

Also assert that we have enough buffer length for all nibbles.

Change-Id: I011f42bca555caec0dfe8688ff1f28303fa04fad
diff --git a/tests/bits/bitrev_test.c b/tests/bits/bitrev_test.c
index b96241c..ed3939a 100644
--- a/tests/bits/bitrev_test.c
+++ b/tests/bits/bitrev_test.c
@@ -208,6 +208,9 @@
 static void sh_chk(const uint8_t *in, uint8_t len, unsigned int nib, bool r)
 {
 	uint8_t x[len];
+	int bytes = nib/2 + (nib & 1);
+	OSMO_ASSERT(len >= bytes);
+	memset(x, 0xcc, len);
 	if (r)
 		osmo_nibble_shift_right(x, in, nib);
 	else
@@ -217,7 +220,7 @@
 	       osmo_hexdump_nospc(in, len), nib);
 	/* do NOT combine those printfs: osmo_hexdump* use static buffer which
 	   WILL screw things up in that case */
-	printf("\n     OUT: %s\n", osmo_hexdump_nospc(x, nib/2));
+	printf("\n     OUT: %s\n", osmo_hexdump_nospc(x, bytes));
 }
 
 int main(int argc, char **argv)
diff --git a/tests/bits/bitrev_test.ok b/tests/bits/bitrev_test.ok
index e6f52af..d2fb12c 100644
--- a/tests/bits/bitrev_test.ok
+++ b/tests/bits/bitrev_test.ok
@@ -63,13 +63,13 @@
 [6] L IN: b00bbabeface, nibble 0:
      OUT: 
 [8] R IN: f00dcafedeadbeef, nibble 1:
-     OUT: 
+     OUT: cc
 [8] L IN: f00dcafedeadbeef, nibble 1:
-     OUT: 
+     OUT: cc
 [6] R IN: b00bbabeface, nibble 1:
-     OUT: 
+     OUT: cc
 [6] L IN: b00bbabeface, nibble 1:
-     OUT: 
+     OUT: cc
 [8] R IN: f00dcafedeadbeef, nibble 2:
      OUT: 0f
 [8] L IN: f00dcafedeadbeef, nibble 2:
@@ -79,13 +79,13 @@
 [6] L IN: b00bbabeface, nibble 2:
      OUT: 00
 [8] R IN: f00dcafedeadbeef, nibble 3:
-     OUT: 0f
+     OUT: 0f00
 [8] L IN: f00dcafedeadbeef, nibble 3:
-     OUT: 00
+     OUT: 00d0
 [6] R IN: b00bbabeface, nibble 3:
-     OUT: 0b
+     OUT: 0b00
 [6] L IN: b00bbabeface, nibble 3:
-     OUT: 00
+     OUT: 00b0
 [8] R IN: f00dcafedeadbeef, nibble 4:
      OUT: 0f00
 [8] L IN: f00dcafedeadbeef, nibble 4:
@@ -95,13 +95,13 @@
 [6] L IN: b00bbabeface, nibble 4:
      OUT: 00bb
 [8] R IN: f00dcafedeadbeef, nibble 5:
-     OUT: 0f00
+     OUT: 0f00dc
 [8] L IN: f00dcafedeadbeef, nibble 5:
-     OUT: 00dc
+     OUT: 00dca0
 [6] R IN: b00bbabeface, nibble 5:
-     OUT: 0b00
+     OUT: 0b00bb
 [6] L IN: b00bbabeface, nibble 5:
-     OUT: 00bb
+     OUT: 00bba0
 [8] R IN: f00dcafedeadbeef, nibble 6:
      OUT: 0f00dc
 [8] L IN: f00dcafedeadbeef, nibble 6:
@@ -111,13 +111,13 @@
 [6] L IN: b00bbabeface, nibble 6:
      OUT: 00bbab
 [8] R IN: f00dcafedeadbeef, nibble 7:
-     OUT: 0f00dc
+     OUT: 0f00dcaf
 [8] L IN: f00dcafedeadbeef, nibble 7:
-     OUT: 00dcaf
+     OUT: 00dcafe0
 [6] R IN: b00bbabeface, nibble 7:
-     OUT: 0b00bb
+     OUT: 0b00bbab
 [6] L IN: b00bbabeface, nibble 7:
-     OUT: 00bbab
+     OUT: 00bbabe0
 [8] R IN: f00dcafedeadbeef, nibble 8:
      OUT: 0f00dcaf
 [8] L IN: f00dcafedeadbeef, nibble 8:
@@ -127,13 +127,13 @@
 [6] L IN: b00bbabeface, nibble 8:
      OUT: 00bbabef
 [8] R IN: f00dcafedeadbeef, nibble 9:
-     OUT: 0f00dcaf
+     OUT: 0f00dcafed
 [8] L IN: f00dcafedeadbeef, nibble 9:
-     OUT: 00dcafed
+     OUT: 00dcafede0
 [6] R IN: b00bbabeface, nibble 9:
-     OUT: 0b00bbab
+     OUT: 0b00bbabef
 [6] L IN: b00bbabeface, nibble 9:
-     OUT: 00bbabef
+     OUT: 00bbabefa0
 [8] R IN: f00dcafedeadbeef, nibble 10:
      OUT: 0f00dcafed
 [8] L IN: f00dcafedeadbeef, nibble 10:
@@ -143,13 +143,13 @@
 [6] L IN: b00bbabeface, nibble 10:
      OUT: 00bbabefac
 [8] R IN: f00dcafedeadbeef, nibble 11:
-     OUT: 0f00dcafed
+     OUT: 0f00dcafedea
 [8] L IN: f00dcafedeadbeef, nibble 11:
-     OUT: 00dcafedea
+     OUT: 00dcafedead0
 [6] R IN: b00bbabeface, nibble 11:
-     OUT: 0b00bbabef
+     OUT: 0b00bbabefac
 [6] L IN: b00bbabeface, nibble 11:
-     OUT: 00bbabefac
+     OUT: 00bbabeface0
 [8] R IN: f00dcafedeadbeef, nibble 12:
      OUT: 0f00dcafedea
 [8] L IN: f00dcafedeadbeef, nibble 12: