--- /dev/null
+++ dyld/dyld-1066.8/testing/kernel-cache-tests/auxkc-vtable-patching/test.py
@@ -0,0 +1,83 @@
+#!/usr/bin/python3
+
+import os
+import KernelCollection
+from FixupHelpers import *
+
+# This verifies that a kext can bind to another kext
+# foo.kext exports foo and bar.kext uses it
+# We put foo.kext in the base KC so that the patch slot in bar.kext has to know to use the correct fixup level in the fixup chain
+
+def check(kernel_cache):
+    enableLogging = False
+    kernel_cache.buildKernelCollection("x86_64", "/auxkc-vtable-patching/main.kc", "/auxkc-vtable-patching/main.kernel", "/auxkc-vtable-patching/extensions", ["com.apple.foo"], [])
+    kernel_cache.analyze("/auxkc-vtable-patching/main.kc", ["-layout", "-arch", "x86_64"])
+
+    assert len(kernel_cache.dictionary()["dylibs"]) == 2
+    assert kernel_cache.dictionary()["dylibs"][0]["name"] == "com.apple.kernel"
+    assert kernel_cache.dictionary()["dylibs"][1]["name"] == "com.apple.foo"
+
+    # Get the addresses for the symbols we are looking at.  This will make it easier to work out the fixup slots
+    kernel_cache.analyze("/auxkc-vtable-patching/main.kc", ["-symbols", "-arch", "x86_64"])
+    
+    # From foo, we want to know where the vtable is, and the foo() and fooUsed0() slots in that vtable
+    # Foo::foo()
+    fooClassFooVMAddr = findGlobalSymbolVMAddr(kernel_cache, 1, "__ZN3Foo3fooEv")
+    if enableLogging:
+        print("fooClassFooVMAddr: " + fooClassFooVMAddr)
+    # Foo::fooUsed0()
+    fooClassFooUsed0VMAddr = findGlobalSymbolVMAddr(kernel_cache, 1, "__ZN3Foo8fooUsed0Ev")
+    if enableLogging:
+        print("fooClassFooUsed0VMAddr: " + fooClassFooUsed0VMAddr)
+
+
+    # Check the fixups
+    kernel_cache.analyze("/auxkc-vtable-patching/main.kc", ["-fixups", "-arch", "x86_64"])
+    
+    # In vtable for Foo, we match the entry for Foo::foo() by looking for its value on the RHS of the fixup
+    kernelFooFixupAddr = findFixupVMAddr(kernel_cache, "kc(0) + " + fooClassFooVMAddr)
+    if enableLogging:
+        print("kernelFooFixupAddr: " + kernelFooFixupAddr)
+    # Then the following fixup should be to Foo::fooUsed0()
+    kernelFooNextFixupAddr = offsetVMAddr(kernelFooFixupAddr, 8)
+    assert kernel_cache.dictionary()["fixups"][kernelFooNextFixupAddr] == "kc(0) + " + fooClassFooUsed0VMAddr
+
+
+    # -----------------------------------------------------------
+    # Now build an aux cache using the baseline kernel collection
+    kernel_cache.buildAuxKernelCollection("x86_64", "/auxkc-vtable-patching/aux.kc", "/auxkc-vtable-patching/main.kc", "", "/auxkc-vtable-patching/extensions", ["com.apple.bar"], [])
+    kernel_cache.analyze("/auxkc-vtable-patching/aux.kc", ["-layout", "-arch", "x86_64"])
+
+    assert len(kernel_cache.dictionary()["dylibs"]) == 1
+    assert kernel_cache.dictionary()["dylibs"][0]["name"] == "com.apple.bar"
+
+
+    # Get the addresses for the symbols we are looking at.  This will make it easier to work out the fixup slots
+    kernel_cache.analyze("/auxkc-vtable-patching/aux.kc", ["-symbols", "-arch", "x86_64"])
+    
+    # From bar, find the vtable and its override of foo()
+    # Bar::foo()
+    barFooVMAddr = findGlobalSymbolVMAddr(kernel_cache, 0, "__ZN3Bar3fooEv")
+    if enableLogging:
+        print("barFooVMAddr: " + barFooVMAddr)
+
+
+    # Check the fixups
+    kernel_cache.analyze("/auxkc-vtable-patching/aux.kc", ["-fixups", "-arch", "x86_64"])
+
+    # Now in bar, again match the entry for its Bar::foo() symbol
+    fixupAddr = findAuxFixupVMAddr(kernel_cache, 0, "kc(3) + " + barFooVMAddr)
+    if enableLogging:
+        print("fixupAddr: " + fixupAddr)
+
+    # And if the patching was correct, then following entry should be to Foo::fooUsed0()
+    nextFixupAddr = offsetVMAddr(fixupAddr, 8)
+    offsetOfFooUsed0 = offsetVMAddr(fooClassFooUsed0VMAddr, -16384)
+    assert kernel_cache.dictionary()["dylibs"][0]["fixups"][nextFixupAddr] == "kc(0) + " + offsetOfFooUsed0
+
+
+# [~]> xcrun -sdk macosx.internal cc -arch x86_64 -Wl,-static -mkernel -nostdlib -Wl,-e,__start -Wl,-pie main.cpp -Wl,-pagezero_size,0x0 -o main.kernel -Wl,-image_base,0x10000 -Wl,-segaddr,__HIB,0x4000 -Wl,-add_split_seg_info -Wl,-install_name,/usr/lib/swift/split.seg.v2.hack -iwithsysroot /System/Library/Frameworks/Kernel.framework/Headers -Wl,-sectcreate,__LINKINFO,__symbolsets,SymbolSets.plist -Wl,-segprot,__LINKINFO,r--,r--
+# [~]> xcrun -sdk macosx.internal cc -arch x86_64 -Wl,-kext -mkernel -nostdlib -Wl,-add_split_seg_info -Wl,-no_data_const foo.cpp -o extensions/foo.kext/foo -iwithsysroot /System/Library/Frameworks/Kernel.framework/Headers -DFOO_USED=1
+# [~]> xcrun -sdk macosx.internal cc -arch x86_64 -Wl,-kext -mkernel -nostdlib -Wl,-add_split_seg_info -Wl,-data_const bar.cpp -o extensions/bar.kext/bar -iwithsysroot /System/Library/Frameworks/Kernel.framework/Headers
+# [~]> rm -r extensions/*.kext/*.ld
+