# Test that a migrated report or pipeline matches the old one

A parity-testing plan for migrations that compares old and new outputs at the right level, with tolerances and sign-off criteria.

- Topic: Data & Analysis
- Framework: RTF
- Level: Standard
- Tags: Sales, Data & Analytics, Coding, Plan, Fill-in Template
- Source: https://www.thinkwithprompt.com/prompts/test-that-a-migrated-report-or-pipeline-matches-the-old-one

## Prompt

```text
Help me plan parity testing to prove a migrated report, model, or pipeline produces the same results as the legacy version.

**What is being migrated:** [e.g. "SSRS reports to Power BI", "on-prem SQL ETL to dbt on Snowflake", "SAS model to Python"]
**Key outputs:** [tables, metrics, reports, model scores]
**Known intentional changes:** [logic fixes, new definitions, timezone or rounding changes]
**Data volume and history:** [rows, years of history]
**Go-live date and who signs off:** [DETAILS]

Steps:
1. Define comparison levels, from coarse to fine: row counts, control totals per period, totals by key dimensions, and row-level key matching with column-by-column comparison.
2. Set tolerances per metric (exact match vs. small rounding differences) and state them before testing begins.
3. Choose the test periods: recent data, a month-end or year-end, edge cases (leap days, restatements, late-arriving data, deletions).
4. Describe how to compare: the query pattern for full outer join on keys, classifying rows as matched, missing in new, missing in old, or values differ.
5. Plan how to triage differences: expected (from intentional changes, documented), bug in new, or bug in old.
6. Define sign-off criteria and a parallel-run period before switching off the old system.

Return:
- A test plan table: Output | Comparison level | Method | Tolerance | Period | Owner.
- Template SQL for the comparison queries in [DIALECT].
- A difference log template: ID | Output | Description | Root cause | Category | Resolution.
- A go-live checklist.
```

## What to fill in

- tables, metrics, reports, model scores
- logic fixes, new definitions, timezone or rounding changes
- rows, years of history
- DETAILS
- DIALECT

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