Fix isUpperCase/isLowerCase constraint checking in python yaml proces…

…sing.

I just got a CI failure like so:

TEST OUT: isUpperCase: true <-- The response "9659674627744477" contains lowercase characters: [].

but of course it does not.  It just happens to be an instance name that didn't
end up using any hex chars that are > 9.

This change better aligns the way Python tests uppercase/lowercase with the
built-in chip-tool constraint impl.

scripts/py_matter_yamltests/matter_yamltests/constraints.py

@@ -582,7 +582,11 @@ def __init__(self, context, is_upper_case):
         self._is_upper_case = is_upper_case
 
     def check_response(self, value, value_type_name) -> bool:
-        return value.isupper() == self._is_upper_case
+        # isupper() on the whole string will return false for digit-only
+        # strings, which is not what we want here.  We want to treat digits as
+        # uppercase for purposes of isUpperCase.
+        isUpper = all(c.isdigit() or c.isupper() for c in value)
+        return isUpper == self._is_upper_case
 
     def get_reason(self, value, value_type_name) -> str:
         if self._is_upper_case:
@@ -608,7 +612,11 @@ def __init__(self, context, is_lower_case):
         self._is_lower_case = is_lower_case
 
     def check_response(self, value, value_type_name) -> bool:
-        return value.islower() == self._is_lower_case
+        # islower() on the whole string will return false for strings consisting
+        # of only digits, which is not what we want here.  We want to treat digits as
+        # lowercase for purposes of isLowerCase.
+        hasUpper = any(c.isupper() for c in value)
+        return hasUpper != self._is_lower_case
 
     def get_reason(self, value, value_type_name) -> str:
         if self._is_lower_case:

src/app/tests/suites/TestConstraints.yaml

@@ -234,6 +234,21 @@ tests:
               isUpperCase: false
               isLowerCase: false
 
+    - label: "Write attribute CHAR_STRING Value with only digits"
+      command: "writeAttribute"
+      attribute: "char_string"
+      arguments:
+          value: "1234567890"
+
+    - label:
+          "Read attribute CHAR_STRING Value isLowerCase/isUpperCase Constraints"
+      command: "readAttribute"
+      attribute: "char_string"
+      response:
+          constraints:
+              isUpperCase: true
+              isLowerCase: true
+
     - label: "Write attribute CHAR_STRING Value"
       command: "writeAttribute"
       attribute: "char_string"