diff -r 34120a385fc8 -r aa0d09f2d81c tests/test_buffer.cpp
--- a/tests/test_buffer.cpp	Sun Apr 16 21:09:25 2023 +0200
+++ b/tests/test_buffer.cpp	Sun Apr 16 21:35:08 2023 +0200
@@ -127,6 +127,24 @@
     EXPECT_TRUE(alloc.verify());
 }
 
+TEST(BufferInit, OnHeap) {
+    CxTestingAllocator alloc;
+    CxBuffer *buf;
+    void *space = cxMalloc(&alloc, 16);
+    buf = cxBufferCreate(space, 16, &alloc, CX_BUFFER_FREE_CONTENTS);
+    EXPECT_NE(buf, nullptr);
+    expect_default_flush_config(buf);
+    EXPECT_EQ(buf->space, space);
+    EXPECT_EQ(buf->flags & CX_BUFFER_AUTO_EXTEND, 0);
+    EXPECT_EQ(buf->flags & CX_BUFFER_FREE_CONTENTS, CX_BUFFER_FREE_CONTENTS);
+    EXPECT_EQ(buf->pos, 0);
+    EXPECT_EQ(buf->size, 0);
+    EXPECT_EQ(buf->capacity, 16);
+    EXPECT_EQ(buf->allocator, &alloc);
+    cxBufferFree(buf);
+    EXPECT_TRUE(alloc.verify());
+}
+
 class BufferShiftFixture : public ::testing::Test {
 protected:
     void SetUp() override {