[fixed] Render testId property

[adammahmood]

Fixes #694

Changes proposed:

• Render testId prop to DOM as data-testid={this.props.testId} as originally implemented in: [added] testId prop for use as a test hook #646

Upgrade Path (for changed or removed APIs):

N/A

Acceptance Checklist:

• The commit message follows the guidelines in CONTRIBUTING.md.
• Documentation (README.md) and examples have been updated as needed.
• If this is a code change, a spec testing the functionality has been added.
• If the commit message has [changed] or [removed], there is an upgrade path above.

[coveralls]

Coverage remained the same at 86.697% when pulling aa704e7 on adammahmood:fix-testid-attribute into 1b561fc on reactjs:master.

[diasbruno]

Hi @adammahmood. I think we can close this one in favour of #695. What do you think?

[adammahmood]

@diasbruno Did you intend to reference #695? (as that's this PR)

[diasbruno]

@adammahmood Sorry, mentioned the wrong PR. :) PR #696.

[adammahmood]

@diasbruno No worries. I agree. We should favour #696 and remove references of testId.

[diasbruno]

I think we can merge this PR for v3 and merge #696 for v4. This way we break compatibility on a major release.

[diasbruno]

Thanks, @adammahmood. Soon I'll make a release.