allows merging and unrolling two observations

Error: page.evaluate: Target crashed
at dumpDatabase (tests/utils/database.js:86:33)
at Object.base.extend.forEachTest.auto (tests/fixtures.ts:459:18)

Error: page.reload: Page crashed
Call log:
- waiting for navigation until "load"

at loadDatabaseDump (tests/utils/database.js:189:13)
at tests/merging.spec.js:12:2

Error: page.reload: Page crashed
Call log:
- waiting for navigation until "load"

at loadDatabaseDump (tests/utils/database.js:168:13)
at tests/merging.spec.js:12:2