Add Local Provider Testing Support for Migration E2E Tests & improve integration tests

[tamas-jozsa]

Summary

This PR adds the ability to test v4→v5 migrations with a locally built
provider binary, enabling rapid iteration when fixing provider issues
discovered during migration testing. Additionally includes updated test
expectations to match current provider behavior.

Motivation

During migration testing, we discovered several provider issues causing
drift:

• Device posture rule input.version not being persisted
• Gateway policy fields showing as (known after apply)
• Need to test provider fixes without waiting for releases

Previously, testing provider fixes required:

1. Make provider change
2. Publish provider to registry
3. Update E2E tests to use new version
4. Run tests

This was slow and cumbersome for iterative development.

Changes

1. Local Provider Testing Support

New Feature: --provider flag for run-e2e-tests script

./scripts/run-e2e-tests --provider /path/to/cloudflare-terraform-next

How it works:

• Verifies provider binary exists (shows helpful error if not built)
• Auto-creates .terraformrc-tf-migrate with dev overrides
• Applies dev overrides only to v5 tests (v4 uses registry for
  compatibility)
• Configures TF_CLI_CONFIG_FILE per-command, not globally

Benefits:

• ✅ Test provider fixes immediately after go build
• ✅ No manual config file management
• ✅ v4 tests stay on stable registry versions
• ✅ Clear visual confirmation when local provider is in use

2. Migration Logic Updates

File: internal/resources/zero_trust_gateway_policy/v4_to_v5.go

Updated migration logic to handle v5 provider schema changes for gateway
policies.

3. Test Data Updates

Updated test expectations for resources that changed behavior:

• logpull_retention - Current provider output
• zero_trust_gateway_policy - v5 schema changes
• zero_trust_list - Current provider behavior

Usage Examples

Test with local provider:

  # 1. Build provider
  cd /path/to/cloudflare-terraform-next
  go build .

  # 2. Run E2E tests with local provider
  cd /path/to/tf-migrate
  ./scripts/run-e2e-tests --provider /path/to/cloudflare-terraform-next

  Test specific resource:
  ./scripts/run-e2e-tests \
    --provider ~/cloudflare-terraform-next \
    --resources zero_trust_device_posture_rule

[tamas-jozsa]

there is no point in having complex test cases for this very simple resource, so I cleaned them up