diff --git a/library/md2.c b/library/md2.c
index 8d887a1..06d6ac2 100644
--- a/library/md2.c
+++ b/library/md2.c
@@ -248,7 +248,7 @@
 /*
  * RFC 1319 test vectors
  */
-static const char md2_test_str[7][81] =
+static const unsigned char md2_test_str[7][81] =
 {
     { "" },
     { "a" },
@@ -256,10 +256,15 @@
     { "message digest" },
     { "abcdefghijklmnopqrstuvwxyz" },
     { "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789" },
-    { "12345678901234567890123456789012345678901234567890123456789012" \
+    { "12345678901234567890123456789012345678901234567890123456789012"
       "345678901234567890" }
 };
 
+static const size_t md2_test_strlen[7] =
+{
+    0, 1, 3, 14, 26, 62, 80
+};
+
 static const unsigned char md2_test_sum[7][16] =
 {
     { 0x83, 0x50, 0xE5, 0xA3, 0xE2, 0x4C, 0x15, 0x3D,
@@ -283,7 +288,7 @@
  */
 int mbedtls_md2_self_test( int verbose )
 {
-    int i;
+    int i, ret = 0;
     unsigned char md2sum[16];
 
     for( i = 0; i < 7; i++ )
@@ -291,12 +296,15 @@
         if( verbose != 0 )
             mbedtls_printf( "  MD2 test #%d: ", i + 1 );
 
-        if( mbedtls_md2_ext( (unsigned char *)md2_test_str[i],
-                             strlen( md2_test_str[i] ), md2sum ) != 0 )
+        ret = mbedtls_md2_ext( md2_test_str[i], md2_test_strlen[i], md2sum );
+        if( ret != 0 )
             goto fail;
 
         if( memcmp( md2sum, md2_test_sum[i], 16 ) != 0 )
+        {
+            ret = 1;
             goto fail;
+        }
 
         if( verbose != 0 )
             mbedtls_printf( "passed\n" );
@@ -311,7 +319,7 @@
     if( verbose != 0 )
         mbedtls_printf( "failed\n" );
 
-    return( 1 );
+    return( ret );
 }
 
 #endif /* MBEDTLS_SELF_TEST */
diff --git a/library/md4.c b/library/md4.c
index 1121fd1..f5972eb 100644
--- a/library/md4.c
+++ b/library/md4.c
@@ -352,7 +352,7 @@
 /*
  * RFC 1320 test vectors
  */
-static const char md4_test_str[7][81] =
+static const unsigned char md4_test_str[7][81] =
 {
     { "" },
     { "a" },
@@ -360,10 +360,15 @@
     { "message digest" },
     { "abcdefghijklmnopqrstuvwxyz" },
     { "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789" },
-    { "12345678901234567890123456789012345678901234567890123456789012" \
+    { "12345678901234567890123456789012345678901234567890123456789012"
       "345678901234567890" }
 };
 
+static const size_t md4_test_strlen[7] =
+{
+    0, 1, 3, 14, 26, 62, 80
+};
+
 static const unsigned char md4_test_sum[7][16] =
 {
     { 0x31, 0xD6, 0xCF, 0xE0, 0xD1, 0x6A, 0xE9, 0x31,
@@ -387,7 +392,7 @@
  */
 int mbedtls_md4_self_test( int verbose )
 {
-    int i;
+    int i, ret = 0;
     unsigned char md4sum[16];
 
     for( i = 0; i < 7; i++ )
@@ -395,12 +400,15 @@
         if( verbose != 0 )
             mbedtls_printf( "  MD4 test #%d: ", i + 1 );
 
-        if( mbedtls_md4_ext( (unsigned char *) md4_test_str[i],
-                             strlen( md4_test_str[i] ), md4sum ) != 0 )
+        ret = mbedtls_md4_ext( md4_test_str[i], md4_test_strlen[i], md4sum );
+        if( ret != 0 )
             goto fail;
 
         if( memcmp( md4sum, md4_test_sum[i], 16 ) != 0 )
+        {
+            ret = 1;
             goto fail;
+        }
 
         if( verbose != 0 )
             mbedtls_printf( "passed\n" );
@@ -415,7 +423,7 @@
     if( verbose != 0 )
         mbedtls_printf( "failed\n" );
 
-    return( 1 );
+    return( ret );
 }
 
 #endif /* MBEDTLS_SELF_TEST */
diff --git a/library/md5.c b/library/md5.c
index 93f6434..68a112a 100644
--- a/library/md5.c
+++ b/library/md5.c
@@ -373,11 +373,11 @@
     { "message digest" },
     { "abcdefghijklmnopqrstuvwxyz" },
     { "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789" },
-    { "12345678901234567890123456789012345678901234567890123456789012" \
+    { "12345678901234567890123456789012345678901234567890123456789012"
       "345678901234567890" }
 };
 
-static const int md5_test_buflen[7] =
+static const size_t md5_test_buflen[7] =
 {
     0, 1, 3, 14, 26, 62, 80
 };
@@ -405,7 +405,7 @@
  */
 int mbedtls_md5_self_test( int verbose )
 {
-    int i;
+    int i, ret = 0;
     unsigned char md5sum[16];
 
     for( i = 0; i < 7; i++ )
@@ -413,12 +413,15 @@
         if( verbose != 0 )
             mbedtls_printf( "  MD5 test #%d: ", i + 1 );
 
-        if( mbedtls_md5_ext( md5_test_buf[i],
-                             md5_test_buflen[i], md5sum ) != 0 )
+        ret = mbedtls_md5_ext( md5_test_buf[i], md5_test_buflen[i], md5sum );
+        if( ret != 0 )
             goto fail;
 
         if( memcmp( md5sum, md5_test_sum[i], 16 ) != 0 )
+        {
+            ret = 1;
             goto fail;
+        }
 
         if( verbose != 0 )
             mbedtls_printf( "passed\n" );
@@ -433,7 +436,7 @@
     if( verbose != 0 )
         mbedtls_printf( "failed\n" );
 
-    return( 1 );
+    return( ret );
 }
 
 #endif /* MBEDTLS_SELF_TEST */
diff --git a/library/ripemd160.c b/library/ripemd160.c
index bf5058f..274a7c9 100644
--- a/library/ripemd160.c
+++ b/library/ripemd160.c
@@ -426,18 +426,22 @@
  * http://homes.esat.kuleuven.be/~bosselae/mbedtls_ripemd160.html#HMAC
  */
 #define TESTS   8
-#define KEYS    2
-static const char *ripemd160_test_input[TESTS] =
+static const unsigned char ripemd160_test_str[TESTS][81] =
 {
-    "",
-    "a",
-    "abc",
-    "message digest",
-    "abcdefghijklmnopqrstuvwxyz",
-    "abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq",
-    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789",
-    "1234567890123456789012345678901234567890"
-        "1234567890123456789012345678901234567890",
+    { "" },
+    { "a" },
+    { "abc" },
+    { "message digest" },
+    { "abcdefghijklmnopqrstuvwxyz" },
+    { "abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq" },
+    { "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789" },
+    { "12345678901234567890123456789012345678901234567890123456789012"
+      "345678901234567890" },
+};
+
+static const size_t ripemd160_test_strlen[TESTS] =
+{
+    0, 1, 3, 14, 26, 56, 62, 80
 };
 
 static const unsigned char ripemd160_test_md[TESTS][20] =
@@ -475,9 +479,8 @@
         if( verbose != 0 )
             mbedtls_printf( "  RIPEMD-160 test #%d: ", i + 1 );
 
-        ret = mbedtls_ripemd160_ext(
-                                (const unsigned char *)ripemd160_test_input[i],
-                                strlen( ripemd160_test_input[i] ), output );
+        ret = mbedtls_ripemd160_ext( ripemd160_test_str[i],
+                                     ripemd160_test_strlen[i], output );
         if( ret != 0 )
             goto fail;
 
diff --git a/library/sha1.c b/library/sha1.c
index 42f3d6c..8d38950 100644
--- a/library/sha1.c
+++ b/library/sha1.c
@@ -405,7 +405,7 @@
     { "" }
 };
 
-static const int sha1_test_buflen[3] =
+static const size_t sha1_test_buflen[3] =
 {
     3, 56, 1000
 };
diff --git a/library/sha256.c b/library/sha256.c
index 0e24d69..b765697 100644
--- a/library/sha256.c
+++ b/library/sha256.c
@@ -380,7 +380,7 @@
     { "" }
 };
 
-static const int sha256_test_buflen[3] =
+static const size_t sha256_test_buflen[3] =
 {
     3, 56, 1000
 };
diff --git a/library/sha512.c b/library/sha512.c
index b1947f1..d0faba9 100644
--- a/library/sha512.c
+++ b/library/sha512.c
@@ -418,7 +418,7 @@
     { "" }
 };
 
-static const int sha512_test_buflen[3] =
+static const size_t sha512_test_buflen[3] =
 {
     3, 112, 1000
 };