Add lint check for integer constants (#775)

script/ci-custom.py

@@ -5,6 +5,7 @@ import codecs
 import collections
 import fnmatch
 import os.path
+import re
 import subprocess
 import sys
 
@@ -143,6 +144,19 @@ def lint_end_newline(fname, content):
     return None
 
 
+@lint_content_check(include=['*.cpp', '*.h', '*.tcc'],
+                    exclude=['esphome/core/log.h'])
+def lint_no_defines(fname, content):
+    errors = []
+    for match in re.finditer(r'#define\s+([a-zA-Z0-9_]+)\s+([0-9bx]+)', content, re.MULTILINE):
+        errors.append(
+            "#define macros for integer constants are not allowed, please use "
+            "`static const uint8_t {} = {};` style instead (replace uint8_t with the appropriate "
+            "datatype). See also Google styleguide.".format(match.group(1), match.group(2))
+        )
+    return errors
+
+
 def relative_cpp_search_text(fname, content):
     parts = fname.split('/')
     integration = parts[2]