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Playwright · 16 Viewport and Responsive Layout
Series contents · Technology map
Stage: Asynchrony, Isolation, and Diagnosis · External example · preview instructions · Storage ID: playwright-step-16
Goals and learning outcomes
- Learning outcome: explain the role of Explicit conditions. Input cases: 390×844 and 1280×800.
- Deliverable: button visibility, note input, and horizontal overflow results. Explain the rationale for handling Core actions, linking it to the code.
Prerequisites
Prepare the experiment results for Keyboard path and Focus from Unit 15, “Keyboard Navigation”.
Key concepts and explanations
Explicit conditions
The viewport affects layout. Reducing screen width alone does not emulate an entire mobile device.
Core actions
Navigation and input must remain possible on small screens. Include actual interactions as well as screenshots.
Practice setup
First check the execution scope guidance on the example screen. The following describes the environment needed to extend the assignment in a separate project. Write and run all tests in a separate Node project using @playwright/test and a dedicated local test origin. The existing playwright-01·02·03 previews only display test source; they do not run Playwright in the iframe. Write new test files yourself for the assignments and judge whether they pass only from actual runner output. Do not use a user profile or storage used for everyday work; preserve CSP and isolation.
The linked example is a starting point. It does not implement every task below. Complete work beyond its supported scope in a separate project.
Practice tasks
- In tests/day-16.spec.ts in a separate practice project, open the table of contents and enter notes in two viewport projects. Refer to the existing Unit 1·14·28 examples only as starting points.
- Input conditions: 390×844 and 1280×800. Baseline: 1280. Run under the baseline conditions, then record observations and errors in notes/day-16.md.
- Variable: width; changed value: 390. Run again through the same input path. Deliverable to save: button visibility, note input, and horizontal overflow results. Hypothesis to check: Keep the main interactions available. Compare it with the actual results, and record whether they agree and why they differ.
Variables to observe
| Variable | Baseline | Change | Expected change / hypothesis |
|---|---|---|---|
| width | 1280 | 390 | Keep the main interactions available. |
Predictions in this table are not measured results. Change one condition at a time and record why the actual result differs.
Completion criteria
- Required deliverable: button visibility, note input, and horizontal overflow results. Results are available for both the baseline and changed conditions, allowing comparison of 2 conditions; input values and the execution environment are recorded together.
- The explanation of differences between the two conditions connects both concepts: Explicit conditions and Core actions. For unexpected items, at least 1 cause or reason they remain unresolved is recorded.
Self-check
- Which processing stage does Explicit conditions affect in this exercise? Input cases: 390×844 and 1280×800.
- Variable: width. Hypothesis to check: Keep the main interactions available. Did the actual results agree with the hypothesis? Explain the evidence in terms of Core actions.
Official references
- Playwright Installation and Execution
- Playwright Locators
- Playwright Assertions
- Playwright Downloads
- Playwright Visual comparisons
Linked example and execution scope
Example source · Runtime environments and limits
Runnable standalone Playwright spec and HTTP fixture; preview does not run tests.
Source code and records are not overwritten automatically. Resetting an existing example also preserves your notes.