Refactor test cases for improved readability and consistency

- Updated test functions in various test files to enhance code clarity by formatting long lines and improving indentation.
- Adjusted assertions to use multi-line formatting for better readability.
- Added new test cases for theme settings API to ensure proper functionality.
- Ensured consistent use of line breaks and spacing across test files for uniformity.

models/opex.py

@@ -28,28 +28,34 @@ class Opex(Base):
 
     @currency_code.setter
     def currency_code(self, value: str) -> None:
-        setattr(self, "_currency_code_pending",
-                (value or "USD").strip().upper())
+        setattr(
+            self, "_currency_code_pending", (value or "USD").strip().upper()
+        )
 
 
 def _resolve_currency_opex(mapper, connection, target):
     if getattr(target, "currency_id", None):
         return
     code = getattr(target, "_currency_code_pending", None) or "USD"
-    row = connection.execute(text("SELECT id FROM currency WHERE code = :code"), {
-                             "code": code}).fetchone()
+    row = connection.execute(
+        text("SELECT id FROM currency WHERE code = :code"), {"code": code}
+    ).fetchone()
     if row:
         cid = row[0]
     else:
         res = connection.execute(
-            text("INSERT INTO currency (code, name, symbol, is_active) VALUES (:code, :name, :symbol, :active)"),
+            text(
+                "INSERT INTO currency (code, name, symbol, is_active) VALUES (:code, :name, :symbol, :active)"
+            ),
             {"code": code, "name": code, "symbol": None, "active": True},
         )
         try:
             cid = res.lastrowid
         except Exception:
-            cid = connection.execute(text("SELECT id FROM currency WHERE code = :code"), {
-                                     "code": code}).scalar()
+            cid = connection.execute(
+                text("SELECT id FROM currency WHERE code = :code"),
+                {"code": code},
+            ).scalar()
     target.currency_id = cid