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.

tests/unit/test_costs.py

@@ -47,8 +47,9 @@ def test_create_and_list_capex_and_opex():
     resp3 = client.get("/api/costs/capex")
     assert resp3.status_code == 200
     data = resp3.json()
-    assert any(item["amount"] == 1000.0 and item["scenario_id"]
-               == sid for item in data)
+    assert any(
+        item["amount"] == 1000.0 and item["scenario_id"] == sid for item in data
+    )
 
     opex_payload = {
         "scenario_id": sid,
@@ -66,8 +67,10 @@ def test_create_and_list_capex_and_opex():
     resp5 = client.get("/api/costs/opex")
     assert resp5.status_code == 200
     data_o = resp5.json()
-    assert any(item["amount"] == 500.0 and item["scenario_id"]
-               == sid for item in data_o)
+    assert any(
+        item["amount"] == 500.0 and item["scenario_id"] == sid
+        for item in data_o
+    )
 
 
 def test_multiple_capex_entries():
@@ -88,8 +91,9 @@ def test_multiple_capex_entries():
     resp = client.get("/api/costs/capex")
     assert resp.status_code == 200
     data = resp.json()
-    retrieved_amounts = [item["amount"]
-                         for item in data if item["scenario_id"] == sid]
+    retrieved_amounts = [
+        item["amount"] for item in data if item["scenario_id"] == sid
+    ]
     for amount in amounts:
         assert amount in retrieved_amounts
 
@@ -112,7 +116,8 @@ def test_multiple_opex_entries():
     resp = client.get("/api/costs/opex")
     assert resp.status_code == 200
     data = resp.json()
-    retrieved_amounts = [item["amount"]
-                         for item in data if item["scenario_id"] == sid]
+    retrieved_amounts = [
+        item["amount"] for item in data if item["scenario_id"] == sid
+    ]
     for amount in amounts:
         assert amount in retrieved_amounts