Singapore H2 Computing Wiki

Paper 2 Lab Skills Drills

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Paper 2 Lab Skills Drills

These are original Paper 2-style practice questions. They use exact file names, function names, test calls, and expected output evidence.

These are small coding drills that practise the habits used during Paper 2: proving files, functions, routes, resources, and final checks one small step at a time.

Detailed answers are in Paper 2 Lab Skills Answers.

Revise the topic hub first:

Questions

Question 1: Folder Setup

Write required_paths() that returns this list:

["app.py", "templates/books.html", "static/style.css", "data/books.csv", "library.db"]

Expected output:

['app.py', 'templates/books.html', 'static/style.css', 'data/books.csv', 'library.db']

[5]

Question 2: Smoke Test

Write smoke_test() that returns "APP STARTED".

Expected output:

APP STARTED

[3]

Question 3: Function Test

Write valid_category(category) that accepts only "Books" and "Stationery". Then write run_validation_tests() using assertions for "Books", "Stationery", and "Food". Return "TESTS PASSED" if all assertions pass.

Expected output:

TESTS PASSED

[5]

Question 4: File Inspection

A CSV file products.csv contains:

product_id,name,price,category
P01,Pen,1.50,Stationery

Write first_csv_row(filename) that returns the first data row as a dictionary.

Expected output:

{'product_id': 'P01', 'name': 'Pen', 'price': '1.50', 'category': 'Stationery'}

[5]

Question 5: JSON Inspection

A JSON file items.json contains:

[{"id": "B01", "title": "Algorithms"}, {"id": "B02", "title": "Networks"}]

Write json_summary(filename) that returns (type_name, first_record), where type_name is the name of the top-level Python type.

Expected output:

('list', {'id': 'B01', 'title': 'Algorithms'})

[5]

Question 6: DB Path Check

Write db_path(filename) that returns the absolute path for filename using Path(filename).resolve().

For marking, print whether db_path("library.db") ends with "library.db".

Expected output:

True

[4]

Question 7: Route Check

Create a minimal Flask app with route / returning "OK". Use Flask’s test client to print the response text.

Expected output:

OK

[5]

Question 8: Submission Script

Write missing_files(required) that returns required paths that do not exist.

For the test, create only:

app.py
templates/books.html

Then test against:

["app.py", "templates/books.html", "static/style.css", "data/books.csv"]

Expected output:

['static/style.css', 'data/books.csv']

[6]

Question 9: Debug Print

Write debug_value(value) that returns repr(value).

Test with a form value containing spaces:

print(debug_value("  Books  "))

Expected output:

'  Books  '

[3]

Question 10: Final Test Plan

Write final_dry_run_report(checks) that returns "READY" only when every check value is True; otherwise return "FIX BEFORE SUBMISSION".

Test:

print(final_dry_run_report({"starts": True, "route_ok": True, "db_ok": True}))
print(final_dry_run_report({"starts": True, "route_ok": False, "db_ok": True}))

Expected output:

READY
FIX BEFORE SUBMISSION

[6]

Review Checklist

After attempting these questions, check whether you can:

  • make required-file checks explicit;
  • create tiny runnable smoke tests before larger features;
  • inspect CSV and JSON resources before full processing;
  • verify Flask routes with a test client;
  • convert a final dry-run checklist into clear submission evidence.

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