The storage account name validation in interactive mode was failing with incomplete error messages when Azure CLI errors occurred. Users would see truncated messages like:

Storage account name 'sttestdev300' is not available:

Instead of helpful information about why the validation failed.

Root Cause

The issue had two parts:

1. Azure CLI errors were suppressed: The 2>$null redirection meant authentication errors and other CLI failures were hidden, causing ConvertFrom-Json to receive no input and return null
2. Case-insensitive regex: PowerShell's default -notmatch operator is case-insensitive, so format validation wasn't catching uppercase letters properly

Changes Made

• Enhanced error handling: Capture Azure CLI stderr with 2>&1 and check $LASTEXITCODE to detect CLI failures
• Improved error messages: Provide specific, actionable error messages for different failure scenarios:
  • Format errors: "Storage account name must be 3-24 lowercase alphanumeric characters."
  • CLI authentication errors: "Storage account name 'name' could not be validated. Azure CLI error: Please run 'az login' to setup account."
  • Name unavailable: "Storage account name 'name' is not available: The storage account named name is already taken."
• Fixed regex case sensitivity: Use -cnotmatch for case-sensitive format validation
• Added comprehensive test coverage: 9 test cases covering all error scenarios
• Cleanup: Removed duplicate unused Test-StorageAccountName.ps1 file

Testing

The fix now handles all failure scenarios gracefully:

# Format validation works correctly
Test-AzStorageAccountName -StorageAccountName "TestAccount"
# Error: Storage account name must be 3-24 lowercase alphanumeric characters.

# Authentication issues are clear
Test-AzStorageAccountName -StorageAccountName "validname123" 
# Error: Storage account name 'validname123' could not be validated. Azure CLI error: Please run 'az login' to setup account.

Fixes #57.

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