Escape newlines in sqlString so multiline rowConditions produce valid SQL

[ihistand]

Fixes #2201.

Problem

A multiline rowConditions entry compiles to invalid SQL:

config {
  type: "table",
  assertions: {
    rowConditions: [`
      invalidCheck
    `]
  }
}

rowConditionsAssertion embeds the condition twice: once raw inside WHERE NOT (...) (fine — multiline is valid there), and once as a string-literal label via sqlString(...). sqlString only escaped backslashes and single quotes, so a raw newline survived into the single-quoted failing_row_condition literal — which BigQuery rejects, since single-quoted literals can't span multiple lines.

Fix

The bug belongs in sqlString, not the assertion template — any caller that quotes a multiline string hits it. sqlString now also escapes newlines/carriage-returns, turning a raw newline into the two-char \n escape (which parses back to a newline, keeping the literal single-line):

return `'${stringContents
  .replace(/\\/g, "\\\\")
  .replace(/'/g, "\\'")
  .replace(/\n/g, "\\n")
  .replace(/\r/g, "\\r")}'`;

Ordering matters: backslash-doubling runs first, otherwise the \n/\r introduced here would themselves get re-escaped into \\n/\\r and print a literal backslash-n.

The raw WHERE NOT (...) clause is untouched — the multiline expression stays as-authored; only the label literal is normalized:

SELECT
  'a > 0\n  AND b > 0' AS failing_row_condition,
  *
FROM `project.dataset.test`
WHERE NOT (a > 0
  AND b > 0)

Why escape over triple-quoting (the issue's other suggestion): escaping reuses the quote-escaping path already in sqlString, so one code path handles quotes, backslashes, and newlines uniformly. Triple-quoting would need its own rules for embedded '''.

Test

Added a regression test in core/actions/assertion_test.ts that compiles a table with a multiline rowConditions entry and asserts the failing_row_condition literal stays single-line (escaped \n) while the WHERE NOT (...) clause keeps the raw, multiline expression.

This was raised in #2201 and a maintainer invited a PR. Happy to adjust style or placement.