Add unit tests for throttle mapping and filtering

Introduces comprehensive unit tests for potRawToPwm mapping, applyModeRampClamp, throttle filter functions, and resetThrottleState. Updates test setup to use native Arduino stubs and the real CircularBuffer library. Also updates platformio.ini to include CircularBuffer as a dependency.

Author: zjwhitehead

platformio.ini

@@ -74,6 +74,9 @@ build_type = debug
 build_flags =
   -I inc
   -I test/native_stubs
+  -I .pio/libdeps/native-test/CircularBuffer
   -D ARDUINO=1
 build_src_filter = -<*>
 test_ignore = neopixel*
+lib_deps =
+  rlogiacco/CircularBuffer@^1.4.0

test/test_throttle/test_throttle.cpp

@@ -1,9 +1,10 @@
+// Use the native Arduino stubs provided by the repo and the real CircularBuffer
 #include <gtest/gtest.h>
+#include "../native_stubs/Arduino.h"
 
-// Create minimal stubs for ESP32 dependencies to avoid linking issues
-#define ARDUINO_H  // Prevent Arduino.h from being included
-
-// Include the actual source file
+// Include the real implementations under test
+#include "../../inc/sp140/shared-config.h"
+#include "../../inc/sp140/throttle.h"
 #include "../../src/sp140/throttle.cpp"
 
 TEST(ThrottleTest, LimitedThrottleNoLimiting) {
@@ -121,6 +122,83 @@ TEST(ThrottleTest, LimitedThrottleSequentialCalls) {
     EXPECT_EQ(current, 1035);  // 1100 - 65 (reaches target)
 }
 
+// Test potRawToPwm mapping function
+TEST(ThrottleTest, PotRawToPwmMapping) {
+    // Test basic mapping from ADC range (0-4095) to PWM range (1035-1950)
+    EXPECT_EQ(potRawToPwm(0), 1035);        // Min ADC -> Min PWM
+    EXPECT_EQ(potRawToPwm(4095), 1950);     // Max ADC -> Max PWM
+    EXPECT_EQ(potRawToPwm(2047), 1492);     // Mid ADC -> Mid PWM (approx)
+
+    // Test quarter points
+    EXPECT_EQ(potRawToPwm(1024), 1263);     // 25% -> 25% of range
+    EXPECT_EQ(potRawToPwm(3072), 1721);     // 75% -> 75% of range
+}
+
+// Test applyModeRampClamp function
+TEST(ThrottleTest, ApplyModeRampClamp) {
+    int prevPwm;
+
+    // Test CHILL mode (mode 0) - slower ramp, lower max
+    prevPwm = 1035;
+    int result = applyModeRampClamp(1500, prevPwm, 0);
+    EXPECT_EQ(prevPwm, result);  // prevPwm should be updated
+    EXPECT_EQ(result, 1045);     // Should ramp by CHILL_MODE_RAMP_RATE (10)
+
+    // Test SPORT mode (mode 1) - faster ramp, higher max
+    prevPwm = 1035;
+    result = applyModeRampClamp(1500, prevPwm, 1);
+    EXPECT_EQ(result, 1062);     // Should ramp by SPORT_MODE_RAMP_RATE (27)
+
+    // Test CHILL mode max PWM clamping
+    prevPwm = 1840;
+    result = applyModeRampClamp(1900, prevPwm, 0);
+    EXPECT_EQ(result, 1850);     // Should clamp to CHILL_MODE_MAX_PWM
+
+    // Test SPORT mode allows higher PWM
+    prevPwm = 1840;
+    result = applyModeRampClamp(1900, prevPwm, 1);
+    EXPECT_EQ(result, 1867);     // Should ramp by 27, not clamp yet
+}
+
+// Test throttle filter functions
+TEST(ThrottleTest, ThrottleFiltering) {
+    // Clear buffer first
+    throttleFilterClear();
+
+    // Empty buffer should return 0
+    EXPECT_EQ(throttleFilterAverage(), 0);
+
+    // Add some values and test averaging
+    throttleFilterPush(1000);
+    EXPECT_EQ(throttleFilterAverage(), 1000);
+
+    throttleFilterPush(1200);
+    EXPECT_EQ(throttleFilterAverage(), 1100);  // (1000+1200)/2
+
+    throttleFilterPush(1400);
+    EXPECT_EQ(throttleFilterAverage(), 1200);  // (1000+1200+1400)/3
+
+    // Test reset functionality
+    throttleFilterReset(1500);
+    EXPECT_EQ(throttleFilterAverage(), 1500);  // Should be filled with 1500
+}
+
+// Test resetThrottleState function
+TEST(ThrottleTest, ResetThrottleState) {
+    int prevPwm = 1500;
+
+    // Add some values to buffer first
+    throttleFilterPush(1200);
+    throttleFilterPush(1300);
+    throttleFilterPush(1400);
+
+    // Reset should clear buffer and reset prevPwm
+    resetThrottleState(prevPwm);
+
+    EXPECT_EQ(prevPwm, 1035);              // Should reset to ESC_MIN_PWM
+    EXPECT_EQ(throttleFilterAverage(), 0); // Buffer should be empty
+}
+
 int main(int argc, char **argv) {
     ::testing::InitGoogleTest(&argc, argv);
     RUN_ALL_TESTS();