Add unit tests for analytics, fallback client, and refactored validators

- Implemented comprehensive unit tests for the BuddAI Analytics module, covering fallback statistics calculations.
- Created tests for the FallbackClient to ensure proper escalation to various AI models and handling of missing API keys.
- Developed unit tests for the refactored validator system, validating various hardware and coding standards.
- Established a base validator interface and implemented specific validators for ESP32, Arduino, motor control, memory safety, and more.
- Enhanced the validator registry to auto-discover and manage validators effectively.
- Included detailed validation logic for common issues in embedded systems programming, such as unused variables, safety timeouts, and coding style violations.

validators/arduino_compat.py

@@ -0,0 +1,51 @@
+import re
+from . import BaseValidator
+
+class ArduinoValidator(BaseValidator):
+    def validate(self, code: str, hardware: str, user_message: str) -> list[dict]:
+        issues = []
+        
+        # Check 9: Unnecessary Wire.h
+        wire_include = re.search(r'#include\s+[<"]Wire\.h[>"]', code)
+        if wire_include:
+            rest_of_code = code.replace(wire_include.group(0), "")
+            if not re.search(r'\bWire\b', rest_of_code):
+                issues.append({
+                    "severity": "error",
+                    "line": self.find_line(code, wire_include.group(0)),
+                    "message": "Unnecessary #include <Wire.h> detected.",
+                    "fix": lambda c: re.sub(r'#include\s+[<"]Wire\.h[>"]', '// [Auto-Fix] Removed unnecessary Wire.h', c)
+                })
+
+        # Check 12: Undefined Pin Constants
+        pin_vars = set(re.findall(r'(?:digitalRead|digitalWrite|pinMode|ledcAttachPin)\s*\(\s*([a-zA-Z_]\w+)', code))
+        for var in pin_vars:
+            if var in ['LED_BUILTIN', 'HIGH', 'LOW', 'INPUT', 'OUTPUT', 'INPUT_PULLUP', 'true', 'false']:
+                continue
+            
+            is_defined = re.search(r'#define\s+' + re.escape(var) + r'\b', code) or \
+                         re.search(r'\b(?:const\s+)?(?:int|byte|uint8_t|short)\s+' + re.escape(var) + r'\s*=', code)
+            
+            if not is_defined:
+                issues.append({
+                    "severity": "error",
+                    "message": f"Undefined variable '{var}' used in pin operation.",
+                    "fix": lambda c, v=var: f"#define {v} 2 // [Auto-Fix] Defined missing pin\n" + c
+                })
+
+        # Check 25: Missing Serial.begin
+        if re.search(r'Serial\.(?:print|write|println|printf)', code) and not re.search(r'Serial\.begin\s*\(', code):
+            issues.append({
+                "severity": "error",
+                "message": "Missing Serial.begin() initialization.",
+                "fix": lambda c: re.sub(r'void\s+setup\s*\(\s*\)\s*\{', r'void setup() {\n  Serial.begin(115200);', c, count=1)
+            })
+
+        # Check 26: Missing Wire.begin
+        if re.search(r'Wire\.(?!h\b|begin\b)', code) and not re.search(r'Wire\.begin\s*\(', code):
+            issues.append({
+                "severity": "error",
+                "message": "Missing Wire.begin() initialization for I2C.",
+                "fix": lambda c: re.sub(r'void\s+setup\s*\(\s*\)\s*\{', r'void setup() {\n  Wire.begin();', c, count=1)
+            })
+        return issues