--- /dev/null
+++ libmalloc/libmalloc-283/tests/posix_memalign_test.c
@@ -0,0 +1,79 @@
+//
+//  posix_memalign_test.c
+//  libmalloc
+//
+//  test allocating and freeing all sizes and alignments
+//
+
+#include <darwintest.h>
+#include <errno.h>
+#include <malloc/malloc.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+T_GLOBAL_META(T_META_RUN_CONCURRENTLY(true));
+
+static inline void*
+t_posix_memalign(size_t alignment, size_t size)
+{
+	void *ptr = NULL;
+	int result = posix_memalign(&ptr, alignment, size);
+	size_t allocated_size = malloc_size(ptr);
+
+	T_QUIET; T_ASSERT_NOTNULL(ptr, "allocation");
+	T_QUIET; T_ASSERT_EQ((intptr_t)ptr % alignment, 0ul, "pointer should be properly aligned");
+	T_QUIET; T_EXPECT_LE(size, allocated_size, "allocation size");
+
+	// Scribble memory pointed to by `ptr` to make sure we're not using that
+	// memory for control structures. This also makes sure the memory can be
+	// written to.
+	const uint64_t pat = 0xdeadbeefcafebabeull;
+	memset_pattern8(ptr, &pat, size);
+	return ptr;
+}
+
+T_DECL(posix_memalign_free, "posix_memalign all power of two alignments <= 4096")
+{
+	for (size_t alignment = sizeof(void*); alignment < 4096; alignment *= 2) {
+		// test several sizes
+		for (size_t size = alignment; size <= 256*alignment; size += 8) {
+			void* ptr = t_posix_memalign(alignment, size);
+			free(ptr);
+		}
+	}
+}
+
+T_DECL(posix_memalign_alignment_not_a_power_of_2, "posix_memalign should return EINVAL if alignment is not a power of 2")
+{
+	{
+		void *ptr = NULL;
+		int result = posix_memalign(&ptr, 24, 48); // alignment is even, but not a power of two
+		T_QUIET; T_ASSERT_NULL(ptr, "ptr should be null");
+		T_QUIET; T_ASSERT_EQ(result, EINVAL, "posix_memalign should return EINVAL");
+	}
+
+	{
+		void *ptr = NULL;
+		int result = posix_memalign(&ptr, 23, 46); // alignment is odd, and not a power of two
+		T_QUIET; T_ASSERT_NULL(ptr, "ptr should be null");
+		T_QUIET; T_ASSERT_EQ(result, EINVAL, "posix_memalign should return EINVAL");
+	}
+}
+
+T_DECL(posix_memalign_alignment_not_a_multiple_of_voidstar, "posix_memalign should return EINVAL if alignment is not a multiple of sizeof(void*)")
+{
+	void *ptr = NULL;
+	const size_t alignment = sizeof(void*)+1;
+	int result = posix_memalign(&ptr, alignment, alignment * 2);
+	T_QUIET; T_ASSERT_NULL(ptr, "ptr should be null");
+	T_QUIET; T_ASSERT_EQ(result, EINVAL, "posix_memalign should return EINVAL");
+}
+
+T_DECL(posix_memalign_allocate_size_0, "posix_memalign should return something that can be passed to free() when size is 0")
+{
+	void *ptr = NULL;
+	int result = posix_memalign(&ptr, 8, 0);
+	T_QUIET; T_ASSERT_EQ(result, 0, "posix_memalign should not return an error when asked for size 0");
+	free(ptr);
+}