webforms-characterization

name	webforms-characterization
description	Use this skill to capture the current behavior of an ASP.NET WebForms workflow before any refactoring begins. Produces Playwright E2E tests and/or golden-master approval tests that act as the migration oracle. Invoke before extracting business logic from any VB event handler.
argument-hint	[workflow/page name] [critical validations] [DB/SOAP dependencies] [test environment URL]

WebForms Characterization Skill

When to Use

• Before refactoring or extracting any VB event handler.
• Before rebuilding a WebForms page in ASP.NET Core.
• When you need to confirm that a change has not broken existing behavior.

Prerequisite

• A running instance of the legacy WebForms application (local or test environment).
• A test database with representative data OR the ability to seed data before each test run.
• A test SOAP endpoint OR an agreed stub/fake for SOAP-backed workflows.

Procedure

1. Workflow Discovery

Identify for the target page/workflow:

• URL and entry point
• Form fields: names, types, required/optional, validation rules visible in UI
• User actions: button clicks, dropdowns, auto-complete, tabbed sections
• Expected outputs: what appears on success, what validation errors look like
• Conditional behavior: what shows/hides depending on data or user role

2. Test Plan (document before writing code)

For each workflow, produce a test plan table:

Test ID | Scenario | Input | Expected Output | Covers Rule
T01     | Happy path | valid data | success message | Main submission
T02     | Required field missing | empty name | "Name is required" | Validation
T03     | Invalid format | "abc" in phone | format error | Input format guard
T04     | Edge case | max-length input | accepted or truncated | Boundary

3. Playwright E2E Test Structure

// tests/E2E/[WorkflowName].spec.ts
import { test, expect } from '@playwright/test';

test.describe('[WorkflowName] — characterization', () => {
  test.beforeEach(async ({ page }) => {
    // Seed test data or navigate to known state
    await page.goto('/path/to/legacy-page.aspx');
  });

  test('T01 — happy path submission', async ({ page }) => {
    await page.fill('#ctl00_MainContent_txtName', 'Test User');
    await page.selectOption('#ctl00_MainContent_ddlType', 'Standard');
    await page.click('#ctl00_MainContent_btnSubmit');
    await expect(page.locator('#ctl00_MainContent_lblResult')).toContainText('Success');
  });

  test('T02 — required field validation', async ({ page }) => {
    await page.click('#ctl00_MainContent_btnSubmit');
    await expect(page.locator('.validation-summary')).toBeVisible();
  });
});

4. Approval Tests for Expression Evaluator / Transformation Module

// tests/Unit/ExpressionEvaluatorApprovalTests.cs
using Verify = VerifyXunit.Verifier;

public class ExpressionEvaluatorApprovalTests
{
    [Fact]
    public async Task Evaluate_TypicalInput_MatchesSnapshot()
    {
        var evaluator = new ExpressionEvaluator(); // the VB module under test
        var result = evaluator.Evaluate("INPUT_EXPRESSION", testData);
        await Verify(result);  // creates/compares .verified.txt snapshot
    }

    [Theory]
    [InlineData("", null)]          // empty expression
    [InlineData("EXPR_MAX_LENGTH")] // boundary
    [InlineData("EXPR_ZERO_VAL")]   // zero value edge case
    public async Task Evaluate_EdgeCases_MatchSnapshot(string input) { ... }
}

5. Coverage Checklist

Before declaring characterization complete:

• Happy path covered (data flows through and result is verified)
• All visible validation rules covered
• At least one edge case per input type (empty, max, special chars)
• DB-triggered behavior covered (data loads, data saves)
• SOAP-triggered behavior covered (or stubbed with documented gap)
• Expression evaluator approval tests cover ≥ 10 representative inputs
• Tests run consistently (3 runs, same result each time)

Output

• Committed test files in /tests/E2E/ and /tests/Unit/ or /tests/Approval/
• A CHARACTERIZATION_STATUS.md for the workflow listing: covered scenarios, gaps, and oracle reliability rating (High/Medium/Low)