diff --git a/Makefile b/Makefile
index 2e20778..a6c2c04 100644
--- a/Makefile
+++ b/Makefile
@@ -123,13 +123,6 @@ test/%: test/%.c asn1.a ldap.a
 	$(DIET) $(CC) $(CFLAGS) -o $@ $^ ldap.a asn1.a -lowfat $(LIBS)
 
 .PHONY: clean tar
-clean:
-	rm -f t t[1-9] *.[ao] bindrequest tinyldap ldapclient \
-parse tinyldap_standalone tinyldap_debug ldapclient_str addindex \
-dumpidx idx2ldif md5password ldapdelete dumpacls asn1dump acl \
-mysql2ldif x \
-*.da *.bbg *.bb *.gcov gmon.out *.gcda *.gcno test/bind bind/ebind
-
 tar: clean
 	cd ..; tar cvvf tinyldap.tar.bz2 tinyldap --use=bzip2 --exclude capture --exclude CVS --exclude exp.ldif --exclude polyp* --exclude rfc*
 
@@ -231,3 +224,23 @@ tls_cipherprio.o: tls_cipherprio.c
 tls_connect.o: tls_connect.c tinytls.h asn1.h
 tls_doread.o: tls_doread.c tinytls.h asn1.h
 tls_dowrite.o: tls_dowrite.c tinytls.h asn1.h
+
+WITH_UNITTEST = $(shell grep -l UNITTEST *.c)
+UNITTEST_BIN = $(patsubst %.c, test/%, $(WITH_UNITTEST))
+
+test/%: %.c
+	gcc --coverage -DUNITTEST -o $@ $^ -I.
+	$@
+
+check: $(UNITTEST_BIN)
+	echo done
+
+clean:
+	rm -f t t[1-9] *.[ao] bindrequest tinyldap ldapclient \
+parse tinyldap_standalone tinyldap_debug ldapclient_str addindex \
+dumpidx idx2ldif md5password ldapdelete dumpacls asn1dump acl \
+mysql2ldif x \
+*.da *.bbg *.bb *.gcov gmon.out *.gcda *.gcno test/bind bind/ebind \
+$(UNITTEST_BIN) test/*.gcda test/*.gcno
+
+
diff --git a/fmt_asn1intpayload.c b/fmt_asn1intpayload.c
index effa470..a79d857 100644
--- a/fmt_asn1intpayload.c
+++ b/fmt_asn1intpayload.c
@@ -25,7 +25,8 @@ size_t fmt_asn1intpayload(char* dest,unsigned long l) {
     /* need to store big endian */
     /* n is the number of bits to shift right for the next octet */
     for (i=0, n=(needed-1)*8; i<needed; ++i, n-=8)
-      dest[i]=(l >> n);
+      // shifting by more bits than are in the type is undefined behavior :(
+      dest[i]= (n == sizeof(l)*8) ? 0 : (l >> n);
   }
   return needed;
 }
diff --git a/fmt_asn1sintpayload.c b/fmt_asn1sintpayload.c
index fd18b0c..c071768 100644
--- a/fmt_asn1sintpayload.c
+++ b/fmt_asn1sintpayload.c
@@ -22,7 +22,7 @@ static size_t sintpayloadlen(signed long l) {
   return i;
 }
 
-size_t fmt_asn1intpayload(char* dest,unsigned long l) {
+size_t fmt_asn1sintpayload(char* dest,signed long l) {
   size_t needed=sintpayloadlen(l);
   if (dest) {
     size_t i,n;
@@ -68,7 +68,8 @@ int main() {
   assert(sintpayloadlen(0x7f)==1);
   assert(sintpayloadlen(0x80)==2);
   assert(sintpayloadlen(0x80000000)==5);
-  if (sizeof(long)==8) assert(sintpayloadlen(0x8000000000000000ul)==9);
+  if (sizeof(long)==8) assert(sintpayloadlen(0x8000000000000000ul)==8);
+  if (sizeof(long)==8) assert(sintpayloadlen(0x0083456789abcdeful)==8);
 
   char buf[100];
   buf[1]='!';
diff --git a/scan_asn1BITSTRING.c b/scan_asn1BITSTRING.c
index 14891b3..def75a1 100644
--- a/scan_asn1BITSTRING.c
+++ b/scan_asn1BITSTRING.c
@@ -16,7 +16,7 @@ size_t scan_asn1BITSTRING(const char* src,const char* max,const char** s,size_t*
       if (*l==1 && **s)
 	return 0;
       /* now check if the unused bits are 0 */
-      lastbyte=(*s)[*l+1];
+      lastbyte=(*s)[*l-1];
       if (lastbyte & (0xff >> (8-**s)))
 	return 0;
       *l=(*l-1)*8-(unsigned char)(**s);
@@ -40,8 +40,11 @@ int main() {
   char buf[100];
   const char* s;
   size_t l;
-  strcpy(buf,"\x03\x02\x07\x01");	// 0x03 = UNIVERSAL PRIMITIVE BIT_STRING, 0x02 = length 5, 0x07 = unused bits in last octet, 0x01 = 1
-  assert(scan_asn1BITSTRING(buf,buf+4,&s,&l)==4 && s==buf+2 && l==2);
+  strcpy(buf,"\x03\x04\x06\x6e\x5d\xc0");
+  size_t r = scan_asn1BITSTRING(buf, buf+6, &s, &l);
+  assert(r==6 && s==buf+3 && l==18);
+  strcpy(buf,"\x03\x02\x07\x80");	// 0x03 = UNIVERSAL PRIMITIVE BIT_STRING, 0x02 = length 2, 0x07 = unused bits in last octet, 0x80 = 1
+  assert(scan_asn1BITSTRING(buf,buf+4,&s,&l)==4 && s==buf+3 && l==1);
   assert(scan_asn1BITSTRING(buf,buf+3,&s,&l)==0);	// short input, make scan_asn1string fail
   buf[0]=0x13;	// 0x13 = UNIVERSAL PRIMITIVE PrintableString
   assert(scan_asn1BITSTRING(buf,buf+4,&s,&l)==0);	// scan_asn1string succeeds but line 9 fails
@@ -50,10 +53,10 @@ int main() {
   buf[2]=7; buf[1]=0;
   assert(scan_asn1BITSTRING(buf,buf+4,&s,&l)==0);	// scan_asn1string succeeds but line 11 fails
   strcpy(buf,"\x03\x01\x00");		// length 0 bit string
-  assert(scan_asn1BITSTRING(buf,buf+3,&s,&l)==3 && s==buf+2 && l==1);
+  assert(scan_asn1BITSTRING(buf,buf+3,&s,&l)==3 && s==buf+3 && l==0);
   buf[2]=1;
   assert(scan_asn1BITSTRING(buf,buf+3,&s,&l)==0);	// length 0 but says it has unused bits, return 0 in line 17
-  strcpy(buf,"\x03\x02\x07\x81");	// 0x03 = UNIVERSAL PRIMITIVE BIT_STRING, 0x02 = length 5, 0x07 = unused bits in last octet, 0x01 = 1
+  strcpy(buf,"\x03\x02\x07\x81");	// 0x03 = UNIVERSAL PRIMITIVE BIT_STRING, 0x02 = length 2, 0x07 = unused bits in last octet, 0x81 = invalid
   assert(scan_asn1BITSTRING(buf,buf+4,&s,&l)==0);	// unused bits not 0, return 0 in line 21
   // we only care for 100% coverage of this file, the others have their own unit tests */
 }