Add failing tests for #82

[Wendy Fouchter (Wendystraite)]

Description of the change

Add tests for issue #82.

These tests "passes" for now and can be merged but will not pass when fixed (using vitest's test.fails). Edit: removed the test.fails usage.

The tests shows that when when molecule is first implicit created then explicitely created in strict mode then it doesn't share the same instance in a complex scenario involving toggling on and off the explicit molecule.

The good news :

• The first 2 cases ("Should share the same instance" and "Should propagate changes between instances") are fixed in React 19 due to useMemo changed behavior (see chore: update react to 19 and fix strict mode tests #89)
• The last case still fails BUT is fixed by Issue #64 - order of molecule shouldn't matter #66

Type of change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation or Development tools (readme, specs, tests, code formatting)

[changeset-bot]

⚠️ No Changeset found

Latest commit: 904b12f

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

This PR includes no changesets

When changesets are added to this PR, you'll see the packages that this PR includes changesets for and the associated semver types

Click here to learn what changesets are, and how to add one.

Click here if you're a maintainer who wants to add a changeset to this PR

[Copilot]

Pull Request Overview

Adds a targeted test suite for Issue #82 to verify instance sharing between implicitly and explicitly created molecules, particularly under Strict Mode behavior changes.

• Adds three tests exercising explicit-then-implicit and implicit-then-explicit ordering, including a real-component toggle scenario.
• Introduces render from @testing-library/react to support component-level testing.
• Uses test.fails to mark the known failing path in Strict Mode (implicit then explicit).

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}

[Copilot]

Pull Request Overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated 3 comments.

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}

[Copilot]

Pull Request Overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated 4 comments.

[Copilot]

The variables initialValue, aValue, and bValue are typed as string, but textContent returns string | null. With TypeScript strict mode enabled, this could cause a type error. Consider either:

1. Changing the type to string | null, or
2. Using a non-null assertion operator (!) since in this test context the elements will always have text content, or
3. Using a default value with the nullish coalescing operator (?? "")