diff --git a/src/modules/finda.h b/src/modules/finda.h
index b54a4f7..fc74779 100644
--- a/src/modules/finda.h
+++ b/src/modules/finda.h
@@ -7,7 +7,7 @@ namespace finda {
 
 class FINDA : protected debounce::Debouncer {
 public:
-    inline FINDA()
+    inline constexpr FINDA()
         : debounce::Debouncer(debounce) {};
     void Step(uint16_t time);
     using debounce::Debouncer::Pressed;
diff --git a/src/modules/fsensor.h b/src/modules/fsensor.h
index f62fa9e..6cee4bb 100644
--- a/src/modules/fsensor.h
+++ b/src/modules/fsensor.h
@@ -11,8 +11,9 @@ namespace fsensor {
 
 class FSensor : protected debounce::Debouncer {
 public:
-    inline FSensor()
-        : debounce::Debouncer(debounce) {};
+    inline constexpr FSensor()
+        : debounce::Debouncer(debounce)
+        , reportedFSensorState(false) {};
     void Step(uint16_t time);
     using debounce::Debouncer::Pressed;
 
diff --git a/src/modules/idler.h b/src/modules/idler.h
index a2b77f4..58000b8 100644
--- a/src/modules/idler.h
+++ b/src/modules/idler.h
@@ -11,12 +11,12 @@ namespace idler {
 class Idler {
 public:
     enum {
-        Ready = 0,
+        Ready = 0, // intentionally set as zero in order to allow zeroing the Idler structure upon startup -> avoid explicit initialization code
         Moving,
         Failed
     };
 
-    inline Idler()
+    inline constexpr Idler()
         : state(Ready)
         , plannedEngage(false)
         , plannedSlot(0)
diff --git a/src/modules/motion.h b/src/modules/motion.h
index 865742b..208f701 100644
--- a/src/modules/motion.h
+++ b/src/modules/motion.h
@@ -61,6 +61,8 @@ public:
 /// @@TODO this is subject of discussion and change in the future
 class Motion {
 public:
+    inline constexpr Motion() = default;
+
     /// Init axis driver - @@TODO this should be probably hidden somewhere deeper ... something should manage the axes and their state
     /// especially when the TMC may get randomly reset (deinited)
     void InitAxis(Axis axis);
diff --git a/src/modules/selector.h b/src/modules/selector.h
index 7ec09a6..c48f2b6 100644
--- a/src/modules/selector.h
+++ b/src/modules/selector.h
@@ -16,7 +16,7 @@ public:
         Failed
     };
 
-    inline Selector()
+    inline constexpr Selector()
         : state(Ready)
         , plannedSlot(0)
         , currentSlot(0) {}
diff --git a/tests/unit/logic/feed_to_finda/test_feed_to_finda.cpp b/tests/unit/logic/feed_to_finda/test_feed_to_finda.cpp
index 27b6555..dca5729 100644
--- a/tests/unit/logic/feed_to_finda/test_feed_to_finda.cpp
+++ b/tests/unit/logic/feed_to_finda/test_feed_to_finda.cpp
@@ -31,17 +31,7 @@ bool WhileCondition(logic::FeedToFinda &ff, COND cond, uint32_t maxLoops = 5000)
 TEST_CASE("feed_to_finda::feed_phase_unlimited", "[feed_to_finda]") {
     using namespace logic;
 
-    // no buttons involved ;)
-    hal::adc::TADCData noButtons({ 0 });
-    hal::adc::ReinitADC(0, std::move(noButtons), 1);
-
-    // finda OFF
-    hal::adc::TADCData findaOFF({ 0 });
-    hal::adc::ReinitADC(1, std::move(findaOFF), 1);
-
-    // let's assume we have the filament NOT loaded and active slot 0
-    modules::globals::globals.SetFilamentLoaded(false);
-    modules::globals::globals.SetActiveSlot(0);
+    ForceReinitAllAutomata();
 
     FeedToFinda ff;
     main_loop();
@@ -103,20 +93,7 @@ TEST_CASE("feed_to_finda::feed_phase_unlimited", "[feed_to_finda]") {
 TEST_CASE("feed_to_finda::FINDA_failed", "[feed_to_finda]") {
     using namespace logic;
 
-    // This is a problem - how to reset all the state machines at once?
-    // May be add an #ifdef unit_tests and a reset function for each of the automatons
-
-    // no buttons involved ;)
-    hal::adc::TADCData noButtons({ 0 });
-    hal::adc::ReinitADC(0, std::move(noButtons), 1);
-
-    // finda OFF
-    hal::adc::TADCData findaOFF({ 0 });
-    hal::adc::ReinitADC(1, std::move(findaOFF), 1);
-
-    // let's assume we have the filament NOT loaded and active slot 0
-    modules::globals::globals.SetFilamentLoaded(false);
-    modules::globals::globals.SetActiveSlot(0);
+    ForceReinitAllAutomata();
 
     FeedToFinda ff;
     main_loop();
diff --git a/tests/unit/logic/stubs/main_loop_stub.cpp b/tests/unit/logic/stubs/main_loop_stub.cpp
index b35118d..cc56a14 100644
--- a/tests/unit/logic/stubs/main_loop_stub.cpp
+++ b/tests/unit/logic/stubs/main_loop_stub.cpp
@@ -1,4 +1,7 @@
 #include "main_loop_stub.h"
+
+#include "../../modules/stubs/stub_adc.h"
+
 #include "../../../../src/modules/buttons.h"
 #include "../../../../src/modules/finda.h"
 #include "../../../../src/modules/fsensor.h"
@@ -9,6 +12,8 @@
 #include "../../../../src/modules/permanent_storage.h"
 #include "../../../../src/modules/selector.h"
 
+#include <new> // bring in placement new
+
 logic::CommandBase *currentCommand = nullptr;
 
 // just like in the real FW, step all the known automata
@@ -26,3 +31,34 @@ void main_loop() {
         currentCommand->Step();
     ++tmpTiming;
 }
+
+void ForceReinitAllAutomata() {
+    // This woodoo magic with placement new is just a forced reinit of global instances of firmware's state machines
+    // just for the purposes of separate unit tests. Each unit test needs a "freshly booted firmware" and since all unit tests
+    // in the test binary share the same global data structures, we need some way of making them fresh each time.
+    //
+    // This approach mimics the firmware behavior closely as the firmware initializes its global data structures
+    // on its very start once (by copying static init data from PROGMEM into RAM) - and we need exactly this approach in the unit tests.
+    //
+    // There are multiple other approaches, one of them is adding a special Init() function into each of these state machines.
+    // As this approach might look like a standard and safer way of doing stuff, it has several drawbacks, especially
+    // it needs an explicit call to the Init function every time an object like this is created - this can have negative influence on firmware's code size
+
+    new (&modules::buttons::buttons) modules::buttons::Buttons();
+    new (&modules::leds::leds) modules::leds::LEDs();
+    new (&modules::finda::finda) modules::finda::FINDA();
+    new (&modules::fsensor::fsensor) modules::fsensor::FSensor();
+    new (&modules::idler::idler) modules::idler::Idler();
+    new (&modules::selector::selector) modules::selector::Selector();
+    new (&modules::motion::motion) modules::motion::Motion();
+
+    // no buttons involved ;)
+    hal::adc::ReinitADC(0, hal::adc::TADCData({ 0 }), 1);
+
+    // finda OFF
+    hal::adc::ReinitADC(1, hal::adc::TADCData({ 0 }), 1);
+
+    // let's assume we have the filament NOT loaded and active slot 0
+    modules::globals::globals.SetFilamentLoaded(false);
+    modules::globals::globals.SetActiveSlot(0);
+}
diff --git a/tests/unit/logic/stubs/main_loop_stub.h b/tests/unit/logic/stubs/main_loop_stub.h
index 3392d83..a30b66e 100644
--- a/tests/unit/logic/stubs/main_loop_stub.h
+++ b/tests/unit/logic/stubs/main_loop_stub.h
@@ -2,5 +2,6 @@
 #include "../../../../src/logic/command_base.h"
 
 extern void main_loop();
+extern void ForceReinitAllAutomata();
 
 extern logic::CommandBase *currentCommand;