diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 006fb39..f9cc485 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -3,6 +3,7 @@
 add_executable(mach_detours_tests
         test_dylib_function.cpp
         test_local_function.cpp
+        test_transaction.cpp
 )
 
 # The target function must be in a shared library because otherwise it might be in the same code page as the test.cpp functions.
diff --git a/tests/test_dylib_function.cpp b/tests/test_dylib_function.cpp
index 1cf7cf0..c32679a 100644
--- a/tests/test_dylib_function.cpp
+++ b/tests/test_dylib_function.cpp
@@ -5,10 +5,10 @@
 #include <mach_detours.h>
 
 #include "lib_function.h"
-int (*realLibFunction)() = libFunction;
+static int (*realLibFunction)() = libFunction;
 
 static int libFunctionDetourCounter = 0;
-int libFunctionDetour()
+static int libFunctionDetour()
 {
     libFunctionDetourCounter++;
     return 94;
@@ -75,34 +75,4 @@ TEST_CASE( "Overriding custom function in dylib", "[dylib]" )
         CHECK( libFunctionCounter == 1 );
         CHECK( libFunctionDetourCounter == 0 );
     }
-
-    SECTION( "aborting transaction means no detour" )
-    {
-        REQUIRE( detour_transaction_begin() == err_none );
-        REQUIRE( detour_attach(reinterpret_cast<detour_func_t*>(&realLibFunction), reinterpret_cast<detour_func_t>(libFunctionDetour)) == err_none );
-        CHECK( detour_transaction_abort() == err_none );
-
-        CHECK( realLibFunction == libFunction );
-        CHECK( libFunctionCounter == 0 );
-        CHECK( libFunctionDetourCounter == 0 );
-        CHECK( libFunction() == 42 );
-        CHECK( libFunctionCounter == 1 );
-        CHECK( libFunctionDetourCounter == 0 );
-    }
-
-    SECTION( "an error in a transaction means no detour" )
-    {
-        REQUIRE( detour_transaction_begin() == err_none );
-        REQUIRE( detour_attach(reinterpret_cast<detour_func_t*>(&realLibFunction), reinterpret_cast<detour_func_t>(libFunctionDetour)) == err_none );
-        // cannot detach because trampoline is not yet in place
-        CHECK( detour_detach(reinterpret_cast<detour_func_t*>(&realLibFunction), reinterpret_cast<detour_func_t>(libFunctionDetour)) == KERN_FAILURE );
-        CHECK( detour_transaction_commit() == KERN_FAILURE );
-
-        CHECK( realLibFunction == libFunction );
-        CHECK( libFunctionCounter == 0 );
-        CHECK( libFunctionDetourCounter == 0 );
-        CHECK( libFunction() == 42 );
-        CHECK( libFunctionCounter == 1 );
-        CHECK( libFunctionDetourCounter == 0 );
-    }
 }
diff --git a/tests/test_transaction.cpp b/tests/test_transaction.cpp
new file mode 100644
index 0000000..9885b00
--- /dev/null
+++ b/tests/test_transaction.cpp
@@ -0,0 +1,84 @@
+// Copyright (c) Lysann Tranvouez.  All rights reserved.
+
+#include <catch2/catch_test_macros.hpp>
+
+#include <mach_detours.h>
+
+#include "lib_function.h"
+static int (*realLibFunction)() = libFunction;
+
+static int libFunctionDetourCounter = 0;
+static int libFunctionDetour()
+{
+    libFunctionDetourCounter++;
+    return 94;
+}
+
+TEST_CASE( "Must start a transaction to attach", "[transaction]" )
+{
+    libFunctionCounter = 0;
+    libFunctionDetourCounter = 0;
+
+    CHECK( detour_attach(reinterpret_cast<detour_func_t*>(&realLibFunction), reinterpret_cast<detour_func_t>(libFunctionDetour)) == detour_err_wrong_thread );
+    CHECK( libFunction() == 42 );
+    CHECK( libFunctionCounter == 1 );
+    CHECK( libFunctionDetourCounter == 0 );
+}
+
+TEST_CASE( "Must start a transaction to detach", "[transaction]" )
+{
+    libFunctionCounter = 0;
+    libFunctionDetourCounter = 0;
+
+    REQUIRE( detour_transaction_begin() == err_none );
+    REQUIRE( detour_attach_and_commit(reinterpret_cast<detour_func_t*>(&realLibFunction), reinterpret_cast<detour_func_t>(libFunctionDetour)) == err_none );
+
+    CHECK( detour_detach_and_commit(reinterpret_cast<detour_func_t*>(&realLibFunction), reinterpret_cast<detour_func_t>(libFunctionDetour)) == detour_err_wrong_thread );
+
+    CHECK( libFunction() == 94 );
+    CHECK( libFunctionCounter == 0 );
+    CHECK( libFunctionDetourCounter == 1 );
+
+    CHECK( detour_transaction_begin() == err_none );
+    CHECK( detour_detach_and_commit(reinterpret_cast<detour_func_t*>(&realLibFunction), reinterpret_cast<detour_func_t>(libFunctionDetour)) == err_none );
+
+    CHECK( libFunction() == 42 );
+    CHECK( libFunctionCounter == 1 );
+    CHECK( libFunctionDetourCounter == 1 );
+}
+
+TEST_CASE( "aborting transaction means no detour", "[transaction]" )
+{
+    libFunctionCounter = 0;
+    libFunctionDetourCounter = 0;
+
+    REQUIRE( detour_transaction_begin() == err_none );
+    REQUIRE( detour_attach(reinterpret_cast<detour_func_t*>(&realLibFunction), reinterpret_cast<detour_func_t>(libFunctionDetour)) == err_none );
+    CHECK( detour_transaction_abort() == err_none );
+
+    CHECK( realLibFunction == libFunction );
+    CHECK( libFunctionCounter == 0 );
+    CHECK( libFunctionDetourCounter == 0 );
+    CHECK( libFunction() == 42 );
+    CHECK( libFunctionCounter == 1 );
+    CHECK( libFunctionDetourCounter == 0 );
+}
+
+TEST_CASE( "an error in a transaction means no detour", "[transaction]" )
+{
+    libFunctionCounter = 0;
+    libFunctionDetourCounter = 0;
+
+    REQUIRE( detour_transaction_begin() == err_none );
+    REQUIRE( detour_attach(reinterpret_cast<detour_func_t*>(&realLibFunction), reinterpret_cast<detour_func_t>(libFunctionDetour)) == err_none );
+    // cannot detach because trampoline is not yet in place
+    CHECK( detour_detach(reinterpret_cast<detour_func_t*>(&realLibFunction), reinterpret_cast<detour_func_t>(libFunctionDetour)) == KERN_FAILURE );
+    CHECK( detour_transaction_commit() == KERN_FAILURE );
+
+    CHECK( realLibFunction == libFunction );
+    CHECK( libFunctionCounter == 0 );
+    CHECK( libFunctionDetourCounter == 0 );
+    CHECK( libFunction() == 42 );
+    CHECK( libFunctionCounter == 1 );
+    CHECK( libFunctionDetourCounter == 0 );
+}