diff --git a/src/tests/assemblers/message.c b/src/tests/assemblers/message.c
index 44258dd..a9a2a83 100644
--- a/src/tests/assemblers/message.c
+++ b/src/tests/assemblers/message.c
@@ -50,8 +50,13 @@ main(void)
 	char        buf[513];
 	signed long ret;
 	for (unsigned long i = 0; i < sizeof(str) / sizeof(*str); i++) {
-		if ((ret = uirc_assembler_message(buf, &m[i], sizeof(buf) / sizeof(char))) <= 0) {
-			printf("Failed to convert IRC_User struct to a string. %li\n", ret);
+		if ((ret = uirc_assembler_message(buf, &m[i], sizeof(buf) / sizeof(char))) < 0) {
+			printf("Failed to convert IRC_Message struct to a string. %li\n", ret);
+			return EXIT_FAILURE;
+		}
+		size_t len = strlen(str[i]);
+		if ((size_t) ret != len) {
+			printf("String lenght doesn't match with amount of bytes printed. Expected %li but got %li\n", len, ret);
 			return EXIT_FAILURE;
 		}
 		expect(buf, str[i]);
diff --git a/src/tests/assemblers/tag.c b/src/tests/assemblers/tag.c
index d9f87e1..9000705 100644
--- a/src/tests/assemblers/tag.c
+++ b/src/tests/assemblers/tag.c
@@ -39,7 +39,13 @@ main(void)
 			printf("Failed to convert tag %lu to \"%s\". Error %li\n", i, str[i], ret);
 			return EXIT_FAILURE;
 		}
+		size_t len = strlen(str[i]);
+		if ((size_t) ret != len) {
+			printf("String lenght doesn't match with amount of bytes printed. Expected %li but got %li\n", len, ret);
+			return EXIT_FAILURE;
+		}
 		expect(buf, str[i]);
+		print_irc_tag(&tag[i]);
 	}
 	return EXIT_SUCCESS;
 }
diff --git a/src/tests/assemblers/user.c b/src/tests/assemblers/user.c
index 7e11c9e..11896fd 100644
--- a/src/tests/assemblers/user.c
+++ b/src/tests/assemblers/user.c
@@ -37,6 +37,11 @@ main(void)
 			printf("Failed to convert IRC_User struct to a string. %li\n", ret);
 			return EXIT_FAILURE;
 		}
+		size_t len = strlen(str[i]);
+		if ((size_t) ret != len) {
+			printf("String lenght doesn't match with amount of bytes printed. Expected %li but got %li\n", len, ret);
+			return EXIT_FAILURE;
+		}
 		expect(buf, str[i]);
 		print_irc_user(&u[i]);
 	}
diff --git a/src/tests/common.c b/src/tests/common.c
index 7da349a..6d0c054 100644
--- a/src/tests/common.c
+++ b/src/tests/common.c
@@ -37,7 +37,7 @@ expect(const char* var, const char* exp)
 }
 
 void
-print_irc_message(IRC_Message* ptr)
+print_irc_message(const IRC_Message* ptr)
 {
 #ifdef UIRC_FEATURE_IRCV3
 	printf(DELIMITER);
@@ -57,7 +57,7 @@ print_irc_message(IRC_Message* ptr)
 
 #ifdef UIRC_FEATURE_IRCV3
 void
-print_irc_tag(IRC_Tag* tag)
+print_irc_tag(const IRC_Tag* tag)
 {
 	printf(DELIMITER "tn: %s\n"
 	                 "tv: %s\n"
@@ -69,7 +69,7 @@ print_irc_tag(IRC_Tag* tag)
 #endif /* UIRC_FEATURE_IRCV3 */
 
 void
-print_irc_user(IRC_User* user)
+print_irc_user(const IRC_User* user)
 {
 	printf(DELIMITER "un: %s\n"
 	                 "uu: %s\n"
diff --git a/src/tests/common.h b/src/tests/common.h
index d5350c7..107ee2e 100644
--- a/src/tests/common.h
+++ b/src/tests/common.h
@@ -30,11 +30,11 @@
 
 void expect(const char* var, const char* exp);
 
-void print_irc_message(IRC_Message* ptr);
+void print_irc_message(const IRC_Message* ptr);
 #ifdef UIRC_FEATURE_IRCV3
-void print_irc_tag(IRC_Tag* tag);
+void print_irc_tag(const IRC_Tag* tag);
 #endif /* UIRC_FEATURE_IRCV3 */
-void print_irc_user(IRC_User* user);
+void print_irc_user(const IRC_User* user);
 
 #endif /* UIRC_GUARD_PRIVATE_COMMONTESTS */
 
diff --git a/src/tests/general/fullloop.c b/src/tests/general/fullloop.c
index 53fd823..6ac4816 100644
--- a/src/tests/general/fullloop.c
+++ b/src/tests/general/fullloop.c
@@ -38,12 +38,17 @@ main(void)
 			printf("Failed to convert string to IRC_Message struct.\n");
 			return EXIT_FAILURE;
 		}
-		signed long ret;
-		char        buf[513];
+		ssize_t ret;
+		char    buf[513];
 		if ((ret = uirc_assembler_message(buf, m, sizeof(buf) / sizeof(char))) <= 0) {
 			printf("Failed to convert IRC_Message struct to a string. (%li)\n", ret);
 			return EXIT_FAILURE;
 		}
+		size_t s1 = strlen(str[i]), s2 = strlen(buf);
+		if (s1 != s2) {
+			printf("String lenght doesn't match after parsing and assembly. Expected %li but got %li\n", s1, s2);
+			return EXIT_FAILURE;
+		}
 		expect(buf, str[i]);
 		print_irc_message(m);
 	}