Variable snapshotAssertionConst

Asserts that a value matches a stored snapshot.

This assertion provides unified snapshot testing across multiple test frameworks. It automatically detects the test framework from the context parameter and uses the appropriate snapshot mechanism.

Supported Frameworks:

• node:test: Native assert.snapshot() support
• Jest/Vitest: Coming in Phase 2
• Mocha: Custom snapshot storage
• Any framework: Use explicit string names

Basic Usage:

import test from 'node:test';
import { expect } from 'bupkis';

test('component renders correctly', (t) => {
  const output = renderComponent();
  expect(output, 'to match snapshot', t);
});
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With Custom Serializer:

test('redacts sensitive data', (t) => {
  const data = { public: 'visible', secret: 'password123' };
  expect(data, 'to match snapshot', t, {
    serializer: (value: any) =>
      JSON.stringify({ ...value, secret: '[REDACTED]' }, null, 2),
  });
});
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Multiple Snapshots Per Test:

test('multi-step process', (t) => {
  const step1 = processStep1();
  expect(step1, 'to match snapshot', t, { hint: 'step-1' });

  const step2 = processStep2();
  expect(step2, 'to match snapshot', t, { hint: 'step-2' });

  const step3 = processStep3();
  expect(step3, 'to match snapshot', t, { hint: 'step-3' });
});
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Mocha Usage:

describe('MyComponent', function () {
  it('renders correctly', function () {
    const output = renderComponent();
    expect(output, 'to match snapshot', this);
  });
});
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Explicit Snapshot Names:

test('any framework', () => {
  const output = renderComponent();
  expect(output, 'to match snapshot', 'component-default-state');
});
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Chaining with Other Assertions:

test('validates and snapshots', (t) => {
  const user = getUserData();
  expect(
    user,
    'to satisfy',
    { name: 'Alice' },
    'and',
    'to have property',
    'email',
    'and',
    'to match snapshot',
    t,
  );
});
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Updating Snapshots:

# node:test
node --test --test-update-snapshots

# Jest/Vitest (Phase 2)
vitest -u

# Other frameworks
BUPKIS_UPDATE_SNAPSHOTS=1 npm test
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