diff --git a/core/alloc.c b/core/alloc.c
index 5a96d28..4258a24 100644
--- a/core/alloc.c
+++ b/core/alloc.c
@@ -12,7 +12,7 @@
 struct slabDesc *slubArray[SLUB_SIZE];
 
 int initSlabDesc(struct slabDesc **desc, size_t size);
-int formatPage(struct slabDesc *desc, size_t size);
+static int formatPage(struct slabDesc *desc, size_t size);
 
 int initSlab(void)
 {
@@ -44,7 +44,7 @@ int initSlabDesc(struct slabDesc **desc, size_t size)
         return formatPage((*desc), size);
 }
 
-int formatPage(struct slabDesc *desc, size_t size)
+static int formatPage(struct slabDesc *desc, size_t size)
 {
         char *cur = (char *)desc + sizeof(struct slabDesc);
         ulong i;
diff --git a/core/assert.h b/core/assert.h
new file mode 100644
index 0000000..dad126d
--- /dev/null
+++ b/core/assert.h
@@ -0,0 +1,21 @@
+#pragma once
+#include "stack.h"
+
+#define assert(p) do {	\
+	if (!(p)) {	\
+		printf("BUG at %s:%d assert(%s)\n",	\
+		       __FILE__, __LINE__, #p);			\
+		printStackTrace(5); \
+		while(1){} \
+	}		\
+} while (0)
+
+#define assertmsg(p, ...) do {	\
+	if (!(p)) {	\
+		printf("BUG at %s:%d assert(%s)\n",	\
+		       __FILE__, __LINE__, #p);			\
+		printf(__VA_ARGS__); \
+		printStackTrace(5); \
+		while(1){} \
+	}		\
+} while (0)
diff --git a/core/main.c b/core/main.c
index 4d24459..15b7ca2 100644
--- a/core/main.c
+++ b/core/main.c
@@ -81,10 +81,10 @@ void kmain(unsigned long magic, unsigned long addr)
 
     printf("Setting up Serial link (115200)\n");
     serialSetup(115200);
+    initSlab();
 #ifdef RUN_TEST
     run_test();
 #endif
-    initSlab();
 
     int count = 0;
     while (1) {
diff --git a/drivers/vga.h b/drivers/vga.h
index 5c90649..c6e3d19 100644
--- a/drivers/vga.h
+++ b/drivers/vga.h
@@ -55,3 +55,6 @@ void cursorMove(int x, int y);
 #define pr_devel(fmt, ...) \
 	no_printf(pr_fmt(fmt), ##__VA_ARGS__)
 #endif
+
+#define pr_info(fmt, ...) \
+	printf(pr_fmt(fmt), ##__VA_ARGS__)
diff --git a/tests/test.c b/tests/test.c
index be951c6..7e27989 100644
--- a/tests/test.c
+++ b/tests/test.c
@@ -1,5 +1,7 @@
-#include "list.h"
+#include "alloc.h"
+#include "assert.h"
 #include "klibc.h"
+#include "list.h"
 #include "mem.h"
 #include "paging.h"
 #include "serial.h"
@@ -24,21 +26,31 @@ void testPhymem(void)
 	printf("%d pages allocated\n", allocCount);
 
 	while ((page = list_pop_head(allocated_page_list)) != NULL) {
-		if (page->phy_addr != (ulong)freeCount) {
-			printf("Error page %d modified\n", (ulong)page);
-		}
-		if (unrefPhyPage((ulong)page) < 0) {
-			printf("Failed to free page %d\n", (ulong)page);
-		}
+		assertmsg(page->phy_addr == (ulong)freeCount, "page %d modified", page);
+		assertmsg(unrefPhyPage((ulong)page) >= 0, "Failed to free page %d\n",
+			  (ulong)page);
 		freeCount++;
 	}
 	printf("%d pages freed\n", freeCount);
 
-	if ((page = (struct mem_desc *)allocPhyPage()) == NULL) {
-		printf("Error ! Cannot allocate memory\n");
-	} else {
-		unrefPhyPage((ulong)page);
-	}
+	assertmsg((page = (struct mem_desc *)allocPhyPage()) != NULL, "Cannot allocate memory\n");
+	unrefPhyPage((ulong)page);
+}
+
+static void testAlloc(void)
+{
+	assert(malloc(1));
+	assert(malloc(2));
+	assert(malloc(3));
+	assert(malloc(4));
+	void *malloc1 = malloc(sizeof(void *));
+	void *malloc2 = malloc(sizeof(void *));
+	assert((char *)malloc2 == ((char *)malloc1 + sizeof(void *)));
+	assert(malloc(1024));
+	assert(malloc(1024));
+	assert(malloc(1024));
+	assert(malloc(1024));
+	assert(malloc(1024));
 }
 
 static void testPaging(void)
@@ -52,10 +64,8 @@ static void testPaging(void)
 	int freeCount  = 0;
 
 	while ((page = (struct mem_desc *)allocPhyPage()) != NULL) {
-		if (pageMap((vaddr_t)page, (paddr_t)page, PAGING_MEM_WRITE)){
-			printf("Fail to map page %d\n", allocCount);
-			break;
-		}
+		assertmsg(pageMap((vaddr_t)page, (paddr_t)page, PAGING_MEM_WRITE) == 0,
+		       "Fail to map page %d\n", allocCount);
 		page->phy_addr = allocCount;
 		allocCount++;
 		list_add_tail(allocated_page_list, page);
@@ -63,33 +73,30 @@ static void testPaging(void)
 	printf("%d pages allocated\n", allocCount);
 
 	while ((page = list_pop_head(allocated_page_list)) != NULL) {
-		if (page->phy_addr != (ulong)freeCount) {
-			printf("Error page %d modified\n", (ulong)page);
-		}
-		if (unrefPhyPage((ulong)page) < 0) {
-			printf("Failed to free page %d\n", (ulong)page);
-		}
+		assertmsg(page->phy_addr == (ulong)freeCount, "page modified");
+		assertmsg(unrefPhyPage((ulong)page) >= 0, "Failed to free page %d\n",
+			  (ulong)page);
 		pageUnmap((vaddr_t)page);
 		freeCount++;
 	}
 	printf("%d pages freed\n", freeCount);
 
-	if ((page = (struct mem_desc *)allocPhyPage()) == NULL) {
-		printf("Error ! Cannot allocate memory\n");
-	} else {
-		unrefPhyPage((ulong)page);
-	}
+	assertmsg((page = (struct mem_desc *)allocPhyPage()) != NULL, "Cannot allocate memory\n");
+	unrefPhyPage((ulong)page);
 }
 
-static void test_backtrace_2(int a, int b){
-	printStackTrace(a+b);
+static void test_backtrace_2(int a, int b)
+{
+	printStackTrace(a + b);
 }
 
-static void test_backtrace_1(int a){
+static void test_backtrace_1(int a)
+{
 	test_backtrace_2(a, 3);
 }
 
-void test_backtrace(){
+void test_backtrace()
+{
 	test_backtrace_1(2);
 }
 
@@ -102,6 +109,7 @@ void run_test(void)
 	serialWrite('l');
 	serialWrite('l');
 	serialWrite('o');
+	testAlloc();
 	printf("Testing backtrace\n");
 	test_backtrace();
 }