Test crypto_kdf constants, add _PRIMITIVE

src/libsodium/crypto_kdf/crypto_kdf.c

@@ -2,6 +2,12 @@
 #include "crypto_kdf.h"
 #include "randombytes.h"
 
+const char *
+crypto_kdf_primitive(void)
+{
+    return crypto_kdf_PRIMITIVE;
+}
+
 size_t
 crypto_kdf_bytes_min(void)
 {

src/libsodium/include/sodium/crypto_kdf.h

@@ -30,6 +30,10 @@ size_t crypto_kdf_contextbytes(void);
 SODIUM_EXPORT
 size_t crypto_kdf_keybytes(void);
 
+#define crypto_kdf_PRIMITIVE "blake2b"
+SODIUM_EXPORT
+const char *crypto_kdf_primitive(void);
+
 SODIUM_EXPORT
 int crypto_kdf_derive_from_key(unsigned char *subkey, size_t subkey_len,
                                uint64_t subkey_id,

test/default/kdf.c

@@ -38,6 +38,17 @@ tv_kdf(void)
         }
         sodium_free(subkey);
     }
+
+    assert(strcmp(crypto_kdf_primitive(), crypto_kdf_PRIMITIVE) == 0);
+    assert(crypto_kdf_BYTES_MAX > 0);
+    assert(crypto_kdf_BYTES_MIN <= crypto_kdf_BYTES_MAX);
+    assert(crypto_kdf_bytes_min() == crypto_kdf_BYTES_MIN);
+    assert(crypto_kdf_bytes_max() == crypto_kdf_BYTES_MAX);
+    assert(crypto_kdf_CONTEXTBYTES > 0);
+    assert(crypto_kdf_contextbytes() == crypto_kdf_CONTEXTBYTES);
+    assert(crypto_kdf_KEYBYTES >= 16);
+    assert(crypto_kdf_keybytes() == crypto_kdf_KEYBYTES);
+
     printf("tv_kdf: ok\n");
 }