W-20148320: update readme

[peternhale]

Summary

Updates the README to document which environment variables are required and when they cause initialization errors. This improves developer experience by clearly indicating which environment variables must be set for different test scenarios.

Changes

• Added a "Required?" column to the environment variables table
• Added detailed usage notes explaining when each required variable is needed
• Documented specific error conditions and when they occur
• Added footnotes explaining conditional requirements vs. org authorization requirements

Required Environment Variables

The following environment variables are now clearly marked as required:

Conditionally Required (Yes*)

• VSIX_TO_INSTALL - Required when installExtensions() is called
• USE_EXISTING_PROJECT_PATH - Required when set (path must exist)
• TEST_RESOURCES - Required when validateTestConfig() is called and neither testResources nor workspacePath is set

Required for Org Authorization (Yes**)

• DEV_HUB_USER_NAME - Required when org authorization is needed
• DEV_HUB_ALIAS_NAME - Required when org authorization is needed (has default but must match existing org)
• SFDX_AUTH_URL - Required when authenticating with Salesforce (when no existing auth found)

Impact

This documentation update helps developers:

• Understand which environment variables must be configured before running tests
• Identify the root cause of initialization errors
• Set up their test environment correctly from the start

Related

• Work Item: @W-20148320@

[madhur310]

I can't seem to add a comment on line 36, but since you are updating this - do you mind removing line: The full API documentation is available at [https://forcedotcom.github.io/salesforcedx-vscode-test-tools](https://forcedotcom.github.io/salesforcedx-vscode-test-tools). it wrong and the link doesn't work.

[CristiCanizales]

I made a suggestion for that heh