diff --git a/.gitignore b/.gitignore
index 0fa6fe4..d832d60 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,4 +1,5 @@
 *.o
+*.bin
 
 /config.mk
 
diff --git a/Makefile b/Makefile
index e05cbf5..94031e0 100644
--- a/Makefile
+++ b/Makefile
@@ -2,8 +2,8 @@ include config.mk
 
 run: run-iso
 
-all:     all-kernel   all-iso   all-libk
-clean: clean-kernel clean-iso clean-libk
+all:     all-kernel   all-iso   all-libk   all-test
+clean: clean-kernel clean-iso clean-libk clean-test
 
 all-kernel: all-libk
 	make all -C arch I=$(shell pwd)/include LIBK=$(shell pwd)/libk/libk.a
@@ -25,3 +25,9 @@ all-libk:
 
 clean-libk:
 	make clean -C libk
+
+test-libk: all-libk
+	make run -C test/libk I=$(shell pwd)/include LIBK=$(shell pwd)/libk/libk.a
+
+clean-test:
+	make clean -C test/libk
diff --git a/arch/console.c b/arch/console.c
index 7dfdcb1..6348812 100644
--- a/arch/console.c
+++ b/arch/console.c
@@ -31,7 +31,7 @@ void console_initialize() {
 
 void console_print(const char *const s)
 {
-    console_write(s, strlen(s));
+    console_write(s, kstrlen(s));
 }
 
 void console_putc(const char c) {
diff --git a/arch/kprintf.c b/arch/kprintf.c
index e5c62aa..6ba9aaf 100644
--- a/arch/kprintf.c
+++ b/arch/kprintf.c
@@ -37,7 +37,7 @@ void kprintf(const char *format, ...)
                 case 'd':
                 case 'u':
                 case 'x':
-                    itoa (buf, c, *((int *) arg++));
+                    kitoa (buf, c, *((int *) arg++));
                     p = buf;
                     goto string;
                     break;
diff --git a/arch/paging.c b/arch/paging.c
index 081ef84..1d97b85 100644
--- a/arch/paging.c
+++ b/arch/paging.c
@@ -65,11 +65,11 @@ void paging_initialize()
 
     nframes = mem_end_page / 0x1000;
     frames = (unsigned int*)kmalloc(INDEX_FROM_BIT(nframes));
-    memset(frames, 0, INDEX_FROM_BIT(nframes));
+    kmemset(frames, 0, INDEX_FROM_BIT(nframes));
 
     // Let's make a page directory.
     kernel_dir = (struct page_dir*)kmalloc_a(sizeof(struct page_dir));
-    memset(kernel_dir, 0, sizeof(struct page_dir));
+    kmemset(kernel_dir, 0, sizeof(struct page_dir));
     current_dir = kernel_dir;
 
     // We need to identity map (phys addr = virt addr) from
@@ -116,7 +116,7 @@ struct page *get_page(unsigned int address, unsigned char make, struct page_dir
     if (make) {
         unsigned int tmp;
         dir->tables[table_idx] = (struct page_table*)kmalloc_ap(sizeof(struct page_table), &tmp);
-        memset(dir->tables[table_idx], 0, 0x1000);
+        kmemset(dir->tables[table_idx], 0, 0x1000);
         dir->tables_phys[table_idx] = tmp | 0x7; // PRESENT, RW, US.
         return &dir->tables[table_idx]->pages[address%1024];
     }
diff --git a/arch/protected.c b/arch/protected.c
index 02c015b..06f27be 100644
--- a/arch/protected.c
+++ b/arch/protected.c
@@ -77,7 +77,7 @@ void protected_initialize()
 
     logger_info("Setup IDT.");
 
-    memset(idt_entries, 0, sizeof(idt_entries));
+    kmemset(idt_entries, 0, sizeof(idt_entries));
 
     idt_set_gate(0,  (unsigned int)exception_0,  0x08, 0x8E);
     idt_set_gate(1,  (unsigned int)exception_1,  0x08, 0x8E);
diff --git a/include/kernelmq/stdlib.h b/include/kernelmq/stdlib.h
index 4151564..e99e11e 100644
--- a/include/kernelmq/stdlib.h
+++ b/include/kernelmq/stdlib.h
@@ -1,8 +1,8 @@
 #ifndef KERNELMQ_INCLUDED_STDLIB
 #define KERNELMQ_INCLUDED_STDLIB 1
 
-void memset(void *buffer, unsigned char value, unsigned int size);
-unsigned int strlen(const char *s);
-void itoa(char *buf, int base, int d);
+void kmemset(void *buffer, unsigned char value, unsigned int size);
+unsigned int kstrlen(const char *s);
+void kitoa(char *buf, int base, int d);
 
 #endif
diff --git a/libk/itoa.c b/libk/itoa.c
index 729b3f8..c6d6973 100644
--- a/libk/itoa.c
+++ b/libk/itoa.c
@@ -1,4 +1,4 @@
-void itoa(char *buf, int base, int d)
+void kitoa(char *buf, int base, int d)
 {
     char *p = buf;
     char *p1, *p2;
diff --git a/libk/memset.c b/libk/memset.c
index c79c884..6c7523c 100644
--- a/libk/memset.c
+++ b/libk/memset.c
@@ -1,4 +1,4 @@
-void memset(void *const buffer, const unsigned char value, const unsigned int size)
+void kmemset(void *const buffer, const unsigned char value, const unsigned int size)
 {
     const unsigned char *end = buffer + size;
 
diff --git a/libk/strlen.c b/libk/strlen.c
index 40f47b5..cf73404 100644
--- a/libk/strlen.c
+++ b/libk/strlen.c
@@ -1,4 +1,4 @@
-unsigned int strlen(const char *const s)
+unsigned int kstrlen(const char *const s)
 {
     unsigned int result = 0;
 
diff --git a/test/libk/Makefile b/test/libk/Makefile
new file mode 100644
index 0000000..1b3c96a
--- /dev/null
+++ b/test/libk/Makefile
@@ -0,0 +1,18 @@
+CC = $(CCPREFIX)gcc
+
+CFLAGS = -std=gnu99 -Wall -Wextra
+
+BINS = strlen.bin
+
+run: all $(addprefix run-, $(BINS))
+
+all: $(BINS)
+
+clean:
+	rm -f $(BINS)
+
+run-%.bin: %.bin
+	@./$< && echo "[ OK ] $*" || echo "[FAIL] $*"
+
+%.bin: %.c
+	$(CC) $< -o $@ $(CFLAGS) -I "$(I)" "$(LIBK)"
diff --git a/test/libk/strlen.c b/test/libk/strlen.c
new file mode 100644
index 0000000..045ff89
--- /dev/null
+++ b/test/libk/strlen.c
@@ -0,0 +1,13 @@
+#include <kernelmq/stdlib.h>
+
+#include <assert.h>
+
+int main()
+{
+    assert(kstrlen("") == 0);
+    assert(kstrlen("q") == 1);
+    assert(kstrlen("qwe rty") == 7);
+    assert(kstrlen("qwe\0rty") == 3);
+
+    return 0;
+}