diff --git a/Makefile b/Makefile
index 1f63d45..b1cff16 100644
--- a/Makefile
+++ b/Makefile
@@ -41,10 +41,10 @@ TEST_BINS = $(TEST_OBJS:.o=)
 
 PHONY += test
 test: $(TEST_BINS)
-	@for t in $^; do               \
-	  echo;                        \
-	  echo '***' "$$t.c" '***';    \
-	  "./$$t";                     \
+	@for t in $^; do                                   \
+	  echo;                                            \
+	  echo '***' "$$t.c" '***';                        \
+	  "./$$t" || printf "\n!!! TEST FAILURE !!!\n";    \
 	done
 
 tests/c/test_%.o: tests/c/test_%.c
@@ -66,4 +66,7 @@ clean:
 
 dist-clean: clean
 
+PHONY += build
+build: all
+
 .PHONY: $(PHONY)
diff --git a/include/mh/hashes.h b/include/mh/hashes.h
index 1d00ecd..1285679 100644
--- a/include/mh/hashes.h
+++ b/include/mh/hashes.h
@@ -15,11 +15,12 @@ typedef enum {
 	MH_H_BLAKE2B,
 	MH_H_BLAKE2S,
 
-	HM_H_COUNT // number of hash functions
+	MH_H_COUNT // number of hash functions
 } mh_hash;
 
-// returns default size in bytes of given hash function
-int mh_hash_default_size(mh_hash hash);
+// returns default length in bytes of given hash function
+//  or -1 in case of invalid arguemnt
+int mh_hash_default_length(mh_hash hash);
 
 // returns wire format code of given hash function
 int mh_hash_code(mh_hash hash);
diff --git a/src/hashes.c b/src/hashes.c
index 7be258f..a42768e 100644
--- a/src/hashes.c
+++ b/src/hashes.c
@@ -1,2 +1,47 @@
 /* vim: set ts=8 sw=8 noexpandtab: */
 #include "mh/hashes.h"
+
+
+static const int hash_lengths[] = {
+	20, // sha1
+	32, // sha2-256
+	64, // sha2-512
+	64, // sha3-512
+	45, // sha3-364
+	32, // sha3-256
+	28, // sha3-224
+	16, // shake-128
+	32, // shake-256
+	// TODO(Kubuxu): implement blake lengths
+};
+
+
+int mh_hash_default_length(mh_hash hash) {
+	if (hash > MH_H_SHAKE_256)
+		return -2; // TODO(Kubuxu): remove it after blake is implemented
+	if (hash < 0 || hash >= MH_H_COUNT)
+		return -1;
+
+	return hash_lengths[0];
+}
+
+
+
+
+
+
+/*
+	MH_H_SHA1,
+	MH_H_SHA2_256,
+	MH_H_SHA2_512,
+	MH_H_SHA3_512,
+	MH_H_SHA3_384,
+	MH_H_SHA3_256,
+	MH_H_SHA3_224,
+	MH_H_SHAKE_128,
+	MH_H_SHAKE_256,
+	MH_H_BLAKE2B,
+	MH_H_BLAKE2S,
+
+	HM_H_COUNT // number of hash functions
+ */
diff --git a/tests/c/minunit.h b/tests/c/minunit.h
index 52ad29b..4a36485 100644
--- a/tests/c/minunit.h
+++ b/tests/c/minunit.h
@@ -9,8 +9,8 @@ static char *mu_all_tests(void);
 
 int main(void) {
 	char *result = mu_all_tests();
-	if (result != 0) {
-		printf("%s\n", result);
+	if (result != NULL) {
+		printf("error: %s\n", result);
 	}
 	else {
 		printf("ALL TESTS PASSED\n");
diff --git a/tests/c/test_error_string.c b/tests/c/test_error_string.c
index 1334c3c..79d881e 100644
--- a/tests/c/test_error_string.c
+++ b/tests/c/test_error_string.c
@@ -1,3 +1,4 @@
+/* vim: set ts=8 sw=8 noexpandtab: */
 #include <string.h>
 #include "minunit.h"
 
@@ -12,10 +13,10 @@ static char *test_error_messages_exist(void) {
 		mu_assert(error_buf, strlen(mh_error_string((mh_error) i)));
 	}
 
-	return 0;
+	return NULL;
 }
 
 static char *mu_all_tests(void) {
 	mu_run_test(test_error_messages_exist);
-	return 0;
+	return NULL;
 }
diff --git a/tests/c/test_hashes_length.c b/tests/c/test_hashes_length.c
new file mode 100644
index 0000000..dd702b6
--- /dev/null
+++ b/tests/c/test_hashes_length.c
@@ -0,0 +1,28 @@
+/* vim: set ts=8 sw=8 noexpandtab: */
+#include <string.h>
+#include "minunit.h"
+
+#include "mh/hashes.h"
+
+char error_buf[256];
+
+static char *test_all_hashes_have_lengths(void) {
+	int i = 0;
+	int length = 0;
+	for (; i < MH_H_COUNT; i++) {
+		length = mh_hash_default_length(i);
+		if (length <= 0) {
+			sprintf(error_buf, "mh_hash_default_length: hash %d"
+					" returned invalid (%d) default length",
+					i, length);
+			return error_buf;
+		}
+	}
+	return NULL;
+}
+
+static char *mu_all_tests(void) {
+	mu_run_test(test_all_hashes_have_lengths);
+	return NULL;
+}
+