Test Doubles vs Hook

Problem	Solution Category
Who executes the logic?	Test Doubles
How is execution redirected?	Hook / Detour / Trampoline

Type	Core Idea	Main Purpose	Typical Behavior
Dummy	Placeholder object	Fill required parameters	Never actually used
Stub	Returns predefined data	Control inputs	Returns fixed values
Mock	Verifies interactions	Validate behavior/contracts	Checks calls, arguments, order
Spy	Records calls	Observe interactions later	Stores call history
Fake	Simplified working implementation	Replace real systems	Contains real internal logic

Concept	Core Idea	Main Responsibility
Hook	Intercept behavior	Replace or intercept execution
Detour	Redirect execution flow	Reroute control flow
Inline Hook	Patch machine code directly	Modify function entry
Trampoline	Preserve original execution path	Resume original function

Technique	Mechanism	Modifies Code Section?
Inline Hook	Patch function instructions	YES
IAT Hook	Replace import table entries	NO
GOT/PLT Hook	Replace ELF relocation entries	NO
VTable Hook	Replace virtual function pointers	NO
Breakpoint Hook	Use debug interrupts	NO
LD_PRELOAD	Dynamic linker substitution	NO

Category	Abstract Meaning	Key Question
Test Doubles	Logical substitution	“Who executes the logic?”
Hook / Detour	Control-flow redirection	“How is execution redirected?”
Trampoline	Execution-flow recovery	“How do we continue original execution?”