Minor improvements to Blowfish documentation and tests
diff --git a/include/mbedtls/blowfish.h b/include/mbedtls/blowfish.h
index d904269..e40e17c 100644
--- a/include/mbedtls/blowfish.h
+++ b/include/mbedtls/blowfish.h
@@ -79,7 +79,7 @@
  * \brief          Initialize a Blowfish context.
  *
  * \param ctx      The Blowfish context to be initialized.
- *                 Must not be \c NULL.
+ *                 This must not be \c NULL.
  */
 void mbedtls_blowfish_init( mbedtls_blowfish_context *ctx );
 
@@ -97,9 +97,9 @@
  * \brief          Perform a Blowfish key schedule.
  *
  * \param ctx      The Blowfish context to perform the key schedule on.
- * \param key      The encryption key. Must be a readable buffer of
+ * \param key      The encryption key. This must be a readable buffer of
  *                 length \p keybits Bits.
- * \param keybits  The length of \p key in Bits. Must be between
+ * \param keybits  The length of \p key in Bits. This must be between
  *                 \c 32 and \c 448 and a multiple of \c 8.
  *
  * \return         \c 0 if successful.
@@ -116,8 +116,8 @@
  * \param mode     The mode of operation. Possible values are
  *                 #MBEDTLS_BLOWFISH_ENCRYPT for encryption, or
  *                 #MBEDTLS_BLOWFISH_DECRYPT for decryption.
- * \param input    The input block. Must be a readable buffer of size 8 Bytes.
- * \param input    The output block. Must be a writable buffer of size 8 Bytes.
+ * \param input    The input block. This must be a readable buffer of size 8 Bytes.
+ * \param input    The output block. This must be a writable buffer of size 8 Bytes.
  *
  * \return         \c 0 if successful.
  * \return         A negative error code on failure.
@@ -129,9 +129,7 @@
 
 #if defined(MBEDTLS_CIPHER_MODE_CBC)
 /**
- * \brief          Perform a Blowfish-CBC buffer encryption/decryption
- *                 Length should be a multiple of the block
- *                 size (8 bytes)
+ * \brief          Perform a Blowfish-CBC buffer encryption/decryption.
  *
  * \note           Upon exit, the content of the IV is updated so that you can
  *                 call the function same function again on the following
@@ -146,12 +144,13 @@
  * \param mode     The mode of operation. Possible values are
  *                 #MBEDTLS_BLOWFISH_ENCRYPT for encryption, or
  *                 #MBEDTLS_BLOWFISH_DECRYPT for decryption.
- * \param length   The length of the input data in Bytes.
+ * \param length   The length of the input data in Bytes. This must be
+ *                 multiple of \c 8.
  * \param iv       The initialization vector. This must be an RW buffer
  *                 of length \c 8 Bytes. It is updated by this function.
- * \param input    The input data. Must be a readable buffer of length
+ * \param input    The input data. This must be a readable buffer of length
  *                 \p length Bytes. If \p length if \c 0, it may be \c NULL.
- * \param output   The output data. Must be a writable buffer of length
+ * \param output   The output data. This must be a writable buffer of length
  *                 \p length Bytes. If \p length if \c 0, it may be \c NULL.
  *
  * \return         \c 0 if successful.
@@ -187,11 +186,11 @@
  *                 The value pointed to must be smaller than \c 8.
  *                 It is updated by this function to support the aforementioned
  *                 streaming usage.
- * \param iv       The initialization vector. Must be an RW buffer of
+ * \param iv       The initialization vector. This must be an RW buffer of
  *                 size \c 8 Bytes. It is updated after use.
- * \param input    The input data. Must be a readable buffer of length
+ * \param input    The input data. This must be a readable buffer of length
  *                 \p length Bytes. If \p length if \c 0, it may be \c NULL.
- * \param output   The output data. Must be a writable buffer of length
+ * \param output   The output data. This must be a writable buffer of length
  *                 \p length Bytes. If \p length if \c 0, it may be \c NULL.
  *
  * \return         \c 0 if successful.
@@ -262,10 +261,10 @@
  *                      buffer of length \c 8 Bytes.
  * \param stream_block  The saved stream-block for resuming. This must point to
  *                      an RW buffer of length \c 8 Bytes.
- * \param input         The input data. Must be a readable buffer of length
- *                      \p length Bytes. If \p length if \c 0, it may be \c NULL.
- * \param output        The output data. Must be a writable buffer of length
- *                      \p length Bytes. If \p length if \c 0, it may be \c NULL.
+ * \param input         The input data. This must be a readable buffer of length
+ *                      \p length Bytes. If \p length is \c 0, it may be \c NULL.
+ * \param output        The output data. This must be a writable buffer of length
+ *                      \p length Bytes. If \p length is \c 0, it may be \c NULL.
  *
  * \return              \c 0 if successful.
  * \return              A negative error code on failure.
diff --git a/tests/suites/test_suite_blowfish.function b/tests/suites/test_suite_blowfish.function
index 028ae1a..1d1422a 100644
--- a/tests/suites/test_suite_blowfish.function
+++ b/tests/suites/test_suite_blowfish.function
@@ -12,6 +12,9 @@
 {
     mbedtls_blowfish_context ctx;
     unsigned char buf[16] = { 0 };
+    size_t const valid_keylength = sizeof( buf ) * 8;
+    size_t valid_mode = MBEDTLS_BLOWFISH_ENCRYPT;
+    size_t invalid_mode = 42;
     size_t off;
     ((void) off);
 
@@ -21,53 +24,53 @@
     TEST_INVALID_PARAM_RET( MBEDTLS_ERR_BLOWFISH_BAD_INPUT_DATA,
                             mbedtls_blowfish_setkey( NULL,
                                                      buf,
-                                                     128 ) );
+                                                     valid_keylength ) );
     TEST_INVALID_PARAM_RET( MBEDTLS_ERR_BLOWFISH_BAD_INPUT_DATA,
                             mbedtls_blowfish_setkey( &ctx,
                                                      NULL,
-                                                     128 ) );
+                                                     valid_keylength ) );
 
     TEST_INVALID_PARAM_RET( MBEDTLS_ERR_BLOWFISH_BAD_INPUT_DATA,
                             mbedtls_blowfish_crypt_ecb( NULL,
-                                                     MBEDTLS_BLOWFISH_ENCRYPT,
+                                                     valid_mode,
                                                      buf, buf ) );
     TEST_INVALID_PARAM_RET( MBEDTLS_ERR_BLOWFISH_BAD_INPUT_DATA,
                             mbedtls_blowfish_crypt_ecb( &ctx,
-                                                        42,
+                                                        invalid_mode,
                                                         buf, buf ) );
     TEST_INVALID_PARAM_RET( MBEDTLS_ERR_BLOWFISH_BAD_INPUT_DATA,
                             mbedtls_blowfish_crypt_ecb( &ctx,
-                                                        MBEDTLS_BLOWFISH_ENCRYPT,
+                                                        valid_mode,
                                                         NULL, buf ) );
     TEST_INVALID_PARAM_RET( MBEDTLS_ERR_BLOWFISH_BAD_INPUT_DATA,
                             mbedtls_blowfish_crypt_ecb( &ctx,
-                                                        MBEDTLS_BLOWFISH_ENCRYPT,
+                                                        valid_mode,
                                                         buf, NULL ) );
 
 #if defined(MBEDTLS_CIPHER_MODE_CBC)
     TEST_INVALID_PARAM_RET( MBEDTLS_ERR_BLOWFISH_BAD_INPUT_DATA,
                             mbedtls_blowfish_crypt_cbc( NULL,
-                                                        MBEDTLS_BLOWFISH_ENCRYPT,
+                                                        valid_mode,
                                                         sizeof( buf ),
                                                         buf, buf, buf ) );
     TEST_INVALID_PARAM_RET( MBEDTLS_ERR_BLOWFISH_BAD_INPUT_DATA,
                             mbedtls_blowfish_crypt_cbc( &ctx,
-                                                        42,
+                                                        invalid_mode,
                                                         sizeof( buf ),
                                                         buf, buf, buf ) );
     TEST_INVALID_PARAM_RET( MBEDTLS_ERR_BLOWFISH_BAD_INPUT_DATA,
                             mbedtls_blowfish_crypt_cbc( &ctx,
-                                                        MBEDTLS_BLOWFISH_ENCRYPT,
+                                                        valid_mode,
                                                         sizeof( buf ),
                                                         NULL, buf, buf ) );
     TEST_INVALID_PARAM_RET( MBEDTLS_ERR_BLOWFISH_BAD_INPUT_DATA,
                             mbedtls_blowfish_crypt_cbc( &ctx,
-                                                        MBEDTLS_BLOWFISH_ENCRYPT,
+                                                        valid_mode,
                                                         sizeof( buf ),
                                                         buf, NULL, buf ) );
     TEST_INVALID_PARAM_RET( MBEDTLS_ERR_BLOWFISH_BAD_INPUT_DATA,
                             mbedtls_blowfish_crypt_cbc( &ctx,
-                                                        MBEDTLS_BLOWFISH_ENCRYPT,
+                                                        valid_mode,
                                                         sizeof( buf ),
                                                         buf, buf, NULL ) );
 #endif /* MBEDTLS_CIPHER_MODE_CBC */
@@ -75,37 +78,37 @@
 #if defined(MBEDTLS_CIPHER_MODE_CFB)
     TEST_INVALID_PARAM_RET( MBEDTLS_ERR_BLOWFISH_BAD_INPUT_DATA,
                             mbedtls_blowfish_crypt_cfb64( NULL,
-                                                          MBEDTLS_BLOWFISH_ENCRYPT,
+                                                          valid_mode,
                                                           sizeof( buf ),
                                                           &off, buf,
                                                           buf, buf ) );
     TEST_INVALID_PARAM_RET( MBEDTLS_ERR_BLOWFISH_BAD_INPUT_DATA,
                             mbedtls_blowfish_crypt_cfb64( &ctx,
-                                                          42,
+                                                          invalid_mode,
                                                           sizeof( buf ),
                                                           &off, buf,
                                                           buf, buf ) );
     TEST_INVALID_PARAM_RET( MBEDTLS_ERR_BLOWFISH_BAD_INPUT_DATA,
                             mbedtls_blowfish_crypt_cfb64( &ctx,
-                                                          MBEDTLS_BLOWFISH_ENCRYPT,
+                                                          valid_mode,
                                                           sizeof( buf ),
                                                           NULL, buf,
                                                           buf, buf ) );
     TEST_INVALID_PARAM_RET( MBEDTLS_ERR_BLOWFISH_BAD_INPUT_DATA,
                             mbedtls_blowfish_crypt_cfb64( &ctx,
-                                                          MBEDTLS_BLOWFISH_ENCRYPT,
+                                                          valid_mode,
                                                           sizeof( buf ),
                                                           &off, NULL,
                                                           buf, buf ) );
     TEST_INVALID_PARAM_RET( MBEDTLS_ERR_BLOWFISH_BAD_INPUT_DATA,
                             mbedtls_blowfish_crypt_cfb64( &ctx,
-                                                          MBEDTLS_BLOWFISH_ENCRYPT,
+                                                          valid_mode,
                                                           sizeof( buf ),
                                                           &off, buf,
                                                           NULL, buf ) );
     TEST_INVALID_PARAM_RET( MBEDTLS_ERR_BLOWFISH_BAD_INPUT_DATA,
                             mbedtls_blowfish_crypt_cfb64( &ctx,
-                                                          MBEDTLS_BLOWFISH_ENCRYPT,
+                                                          valid_mode,
                                                           sizeof( buf ),
                                                           &off, buf,
                                                           buf, NULL ) );