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/e2e/test_currencies.py

@@ -12,7 +12,8 @@ def _unique_currency_code(existing: set[str]) -> str:
         if candidate not in existing and candidate != "USD":
             return candidate
     raise AssertionError(
-        "Unable to generate a unique currency code for the test run.")
+        "Unable to generate a unique currency code for the test run."
+    )
 
 
 def _metric_value(page: Page, element_id: str) -> int:
@@ -42,8 +43,9 @@ def test_currency_workflow_create_update_toggle(page: Page) -> None:
     expect(page.locator("h2:has-text('Currency Overview')")).to_be_visible()
 
     code_cells = page.locator("#currencies-table-body tr td:nth-child(1)")
-    existing_codes = {text.strip().upper()
-                      for text in code_cells.all_inner_texts()}
+    existing_codes = {
+        text.strip().upper() for text in code_cells.all_inner_texts()
+    }
 
     total_before = _metric_value(page, "currency-metric-total")
     active_before = _metric_value(page, "currency-metric-active")
@@ -109,7 +111,9 @@ def test_currency_workflow_create_update_toggle(page: Page) -> None:
     toggle_button = row.locator("button[data-action='toggle']")
     expect(toggle_button).to_have_text("Activate")
 
-    with page.expect_response(f"**/api/currencies/{new_code}/activation") as toggle_info:
+    with page.expect_response(
+        f"**/api/currencies/{new_code}/activation"
+    ) as toggle_info:
         toggle_button.click()
     toggle_response = toggle_info.value
     assert toggle_response.status == 200
@@ -126,5 +130,6 @@ def test_currency_workflow_create_update_toggle(page: Page) -> None:
     _expect_feedback(page, f"Currency {new_code} activated.")
 
     expect(row.locator("td").nth(3)).to_contain_text("Active")
-    expect(row.locator("button[data-action='toggle']")
-           ).to_have_text("Deactivate")
+    expect(row.locator("button[data-action='toggle']")).to_have_text(
+        "Deactivate"
+    )