Dexter

Training Plan

A structured 2-week plan for automation engineers learning Python SDET skills with the Dexter project.

---

Overview

Week	Focus	Goal
Week 1	Python foundations + project setup	Write and run basic Python; understand the app
Week 2	Automation deep dive + CI/CD	Build a full test suite; operate CI pipeline

---

Week 1 — Foundations

Day 1: Python Basics

Topics: Data types, variables, operators, collections (list, dict, set, tuple), control flow.

Exercises:

• Write a script that creates a list of 5 sample orders (dicts) and prints each one.
• Filter orders where qty > 1 using a list comprehension.
• Write a function calculate_total(price, qty) that returns the total cost.

Deliverable: scratch/day1_basics.py with the above exercises.

---

Day 2: Functions, Modules, and Error Handling

Topics: Functions, modules, imports, exceptions, logging.

Exercises:

• Refactor calculate_total into a new module src/utils.py.
• Add input validation that raises ValueError for negative price or zero quantity.
• Write a test in tests/api/ that calls the validation logic and asserts the error.

Deliverable: Updated src/utils.py and a passing test.

---

Day 3: Project Setup and App Exploration

Topics: Virtual environments, pip, Flask basics, REST concepts.

Exercises:

• Complete Onboarding Guide setup from scratch.
• Start the app and use curl to call each API endpoint.
• Read src/app.py and src/data_store.py and describe (in comments) what each function does.

Deliverable: Running app with annotated source code comments.

---

Day 4: First API Tests

Topics: pytest basics, fixtures, assertions, HTTP status codes.

Exercises:

• Read tests/api/test_orders_api.py.
• Add tests for: create with missing fields (400), create with invalid price (400), fetch a nonexistent order (404).
• Run pytest -m api -v and confirm all pass.

Deliverable: At least 3 new passing API tests.

---

Day 5: Deeper API Testing

Topics: Parametrize, negative testing, boundary conditions.

Exercises:

• Use @pytest.mark.parametrize to test 4–5 invalid payloads in a single test function.
• Add a test that creates 3 orders and asserts the list endpoint returns all 3.
• Add a test for the update endpoint (PUT).

Deliverable: Parametrized test block + update/list test.

---

Week 2 — Automation and CI/CD

Day 6: Selenium UI Basics

Topics: WebDriver setup, locators, explicit waits, Page Object basics.

Exercises:

• Read tests/ui/test_orders_ui.py.
• Add a test that creates an order through the UI and verifies it appears in the list.
• Replace any time.sleep calls (if present) with WebDriverWait.

Deliverable: 1 new UI test using explicit waits.

---

Day 7: Advanced UI Testing

Topics: Form validation, error messages, dynamic content.

Exercises:

• Add a test that submits an empty form and asserts a validation message appears.
• Add a test that deletes an order through the UI and verifies it is removed.
• Introduce a simple Page Object for the Order Board page.

Deliverable: 2 new UI tests + a Page Object class.

---

Day 8: Code Quality

Topics: black formatting, naming conventions, code review.

Exercises:

• Run black --check . and fix any violations.
• Review your test code against the Best Practices checklist.
• Open a PR for your week’s work and complete the PR checklist in CONTRIBUTING.md.

Deliverable: Formatted, reviewed PR.

---

Day 9: CI/CD

Topics: GitHub Actions, workflow YAML, reading logs.

Exercises:

• Read CI/CD Guide and .github/workflows/ci.yml.
• Push a branch and watch the workflow run in the Actions tab.
• Intentionally break a test, push, observe the failure in CI, then fix it.
• Add a CI status badge to your fork’s README.

Deliverable: PR with a green CI run.

---

Day 10: Interview Prep and Review

Topics: Consolidation, reflection, mock interview prep.

Exercises:

• Review all completed tasks against tasks.md.
• Work through the interview prep checklist below.
• Write 2–3 sentences describing the project for a resume bullet point.

Deliverable: Completed interview prep checklist.

---

Interview Prep Checklist

Use this checklist to self-assess before a Python SDET interview.

Python

• Explain the difference between a list and a tuple; give an automation use case for each.
• Write a function that reads a JSON file and returns a list of dicts.
• Describe what a decorator is and name two used in pytest.

API Automation

• Explain what pytest fixtures are and give an example.
• Describe how you would test a paginated API endpoint.
• What is the difference between a 400 and a 422 status code?
• How do you handle authentication tokens in API tests?

UI Automation (Selenium)

• What is the difference between implicit and explicit waits?
• Describe the Page Object Model (POM) pattern.
• How would you handle a dynamically loaded table in Selenium?
• What causes flaky UI tests and how do you reduce them?

CI/CD

• Describe the steps in the GitHub Actions workflow for this project.
• How would you run only API tests in CI (not UI tests)?
• What is the purpose of a requirements.txt file?

Soft Skills

• How do you decide which tests to automate versus test manually?
• Describe a time a test caught a real bug.
• How do you keep a test suite maintainable as the application grows?

---

Expected Outcomes

By the end of the two-week plan you should be able to:

1. Write Python functions with proper error handling and logging.
2. Design and implement REST API tests with pytest, covering positive and negative cases.
3. Write UI tests with Selenium using explicit waits and a basic Page Object pattern.
4. Run, read, and debug a GitHub Actions CI workflow.
5. Apply code formatting (black) and follow commit conventions.
6. Confidently answer common Python SDET interview questions.

---

Related Guides

• Onboarding — environment setup
• Learning Path — phase-by-phase progression
• Hands-on Tasks — task list
• Best Practices — automation patterns
• Development Guide — branching and workflow