diff --git a/Makefile b/Makefile
index 4907163..edca96b 100644
--- a/Makefile
+++ b/Makefile
@@ -25,7 +25,7 @@ INC_FLAGS := $(addprefix -I,$(INC_DIRS))
 #  object file is also recompiled if only a header is changed.
 # -MP: generate a dummy target for every header file (according to the  docs it
 #  prevents some errors when removing header files)
-CFLAGS ?= -MMD -MP -Wall -Werror -Wextra
+CFLAGS ?= -MMD -MP -Wall -Wextra
 CFLAGS += $(INC_FLAGS)
 
 .PHONY: all
diff --git a/include/vieter_heap.h b/include/vieter_heap.h
new file mode 100644
index 0000000..ffb7da2
--- /dev/null
+++ b/include/vieter_heap.h
@@ -0,0 +1,26 @@
+#ifndef VIETER_HEAP
+#define VIETER_HEAP
+
+#include <stdint.h>
+#include <stddef.h>
+
+typedef struct vieter_heap vieter_heap;
+
+typedef enum vieter_heap_error {
+    vieter_heap_ok = 0,
+    vieter_heap_empty = 1
+} vieter_heap_error;
+
+vieter_heap *vieter_heap_init();
+
+void vieter_heap_free(vieter_heap *heap);
+
+uint64_t vieter_heap_size(vieter_heap *heap);
+
+vieter_heap_error vieter_heap_insert(vieter_heap *heap, uint64_t key, void *data);
+
+vieter_heap_error vieter_heap_pop(void **out, vieter_heap *heap);
+
+vieter_heap_error vieter_heap_peek(void **out, vieter_heap *heap);
+
+#endif
diff --git a/src/heap/heap.c b/src/heap/heap.c
new file mode 100644
index 0000000..7e3669a
--- /dev/null
+++ b/src/heap/heap.c
@@ -0,0 +1,28 @@
+#include "vieter_heap.h"
+
+struct vieter_heap {
+    uint64_t size;
+};
+
+vieter_heap *vieter_heap_init() {
+    return NULL;
+}
+
+uint64_t vieter_heap_size(vieter_heap *heap) {
+    return heap->size;
+}
+
+void vieter_heap_free(vieter_heap *heap) {}
+
+
+vieter_heap_error vieter_heap_insert(vieter_heap *heap, uint64_t key, void *data) {
+    return vieter_heap_ok;
+}
+
+vieter_heap_error vieter_heap_pop(void **out, vieter_heap *heap) {
+    return vieter_heap_ok;
+}
+
+vieter_heap_error vieter_heap_peek(void **out, vieter_heap *heap) {
+    return vieter_heap_ok;
+}
diff --git a/test/heap/test_heap.c b/test/heap/test_heap.c
new file mode 100644
index 0000000..4079569
--- /dev/null
+++ b/test/heap/test_heap.c
@@ -0,0 +1,18 @@
+#include "acutest.h"
+#include "vieter_heap.h"
+
+#define TEST_SIZE(heap, size) \
+    TEST_CHECK(vieter_heap_size(heap) == size); \
+    TEST_MSG("Size: %zu", vieter_heap_size(heap))
+
+void test_init() {
+    vieter_heap *heap = vieter_heap_init();
+    TEST_CHECK(heap != NULL);
+    TEST_SIZE(heap, 0);
+    vieter_heap_free(heap);
+}
+
+TEST_LIST = {
+    {"test_init", test_init},
+    {NULL, NULL}
+};