Fix assertion and add tests

- The jump table is only generated to OUR executable, not e.g. a linked library :-D

HackLib/Process.cpp

@@ -517,13 +517,14 @@ std::vector<uint8_t> Process::ReadFunction(void(*function)(void), size_t size)
 	uint8_t jump[5] = {};
 	process.ReadProcessMemory(address, jump, sizeof(jump));
 
-	_ASSERTE(jump[0] == X86::JmpJz);
-
-	// Make absolute
-	address += jump[1] | (jump[2] << 8) | (jump[3] << 16) | (jump[4] << 24);
-	address += 5; // Size of relative jump
+	if (jump[0] == X86::JmpJz)
+	{
+		// Make absolute
+		address += jump[1] | (jump[2] << 8) | (jump[3] << 16) | (jump[4] << 24);
+		address += 5; // Size of relative jump
 
-	LogDebug << function << "jumps to" << address;
+		LogDebug << function << "jumps to" << address;
+	}
 #endif
 
 	size_t bytesRead = 0;

HackLibTests/ProcessTests.cpp

@@ -1,5 +1,10 @@
 #include "Process.hpp"
 
+extern "C" __declspec(dllexport) int ThisFunctionActuallyExists(int x)
+{
+	return x * 2;
+}
+
 TEST(ProcessTests, Header)
 {
 	DWORD pid = GetCurrentProcessId();
@@ -47,7 +52,7 @@ TEST(ProcessTests, ModuleNotFound)
 		"Neither does this function"), std::range_error);
 }
 
-TEST(ProcessTests, FunctionNotFound)
+TEST(ProcessTests, ImportNotFound)
 {
 	DWORD pid = GetCurrentProcessId();
 	Process currentProcess(pid);
@@ -57,16 +62,59 @@ TEST(ProcessTests, FunctionNotFound)
 		"Neither does this function"), std::range_error);
 }
 
-TEST(ProcessTests, FunctionFound)
+TEST(ProcessTests, ImportFound)
 {
 	DWORD pid = GetCurrentProcessId();
 	Process currentProcess(pid);
 
 	// It's just called above. It has to be found
-	Pointer fnptr = 
+	Pointer actual =
 		currentProcess.FindImportAddress("KERNEL32.dll", "GetCurrentProcessId");
 
-	EXPECT_NE(fnptr, Pointer());
+	EXPECT_NE(actual, Pointer());
+}
+
+TEST(ProcessTests, FunctionNotFound)
+{
+	DWORD pid = GetCurrentProcessId();
+	Process currentProcess(pid);
+
+	EXPECT_THROW(currentProcess.FindFunctionAddress("Derp", "GetCurrentProcessId"), std::runtime_error);
+	EXPECT_THROW(currentProcess.FindFunctionAddress("KERNEL32.dll", "Derp"), std::runtime_error);
+}
+
+TEST(ProcessTests, FunctionFoundExternal)
+{
+	void* getCurrentProcessId = GetCurrentProcessId;
+
+	DWORD pid = GetCurrentProcessId();
+	Process currentProcess(pid);
+
+	Pointer actual =
+		currentProcess.FindFunctionAddress("KERNEL32.dll", "GetCurrentProcessId");
+
+	EXPECT_NE(actual, Pointer());
+
+	Pointer expected(getCurrentProcessId);
+
+	EXPECT_EQ(actual, expected);
+}
+
+TEST(ProcessTests, FunctionFoundInternal)
+{
+	void* thisFunctionActuallyExists = ThisFunctionActuallyExists;
+
+	DWORD pid = GetCurrentProcessId();
+	Process currentProcess(pid);
+
+	Pointer actual =
+		currentProcess.FindFunctionAddress("HackLibTests.exe", "ThisFunctionActuallyExists");
+
+	EXPECT_NE(actual, Pointer());
+
+	Pointer expected(thisFunctionActuallyExists);
+
+	EXPECT_EQ(actual, expected);
 }
 
 TEST(ProcessTests, ResolveSecret)