Documentation

testing.assertEmpty() function

testing.assertEmpty() tests if an input stream is empty. If not empty, the function returns an error.

assertEmpty can be used to perform in-line tests in a query.

Function type signature
(<-tables: stream[A]) => stream[A]

For more information, see Function type signatures.

Parameters

tables

Input data. Default is piped-forward data (<-).

Examples

Check if there is a difference between streams

This example uses testing.diff() to output the difference between two streams of tables. testing.assertEmpty() checks to see if the difference is empty.

import "sampledata"
import "testing"

want = sampledata.int()
got = sampledata.float() |> toInt()

got
    |> testing.diff(want: want)
    |> testing.assertEmpty()

Was this page helpful?

Thank you for your feedback!


New in InfluxDB 3.7

Key enhancements in InfluxDB 3.7 and the InfluxDB 3 Explorer 1.5.

See the Blog Post

InfluxDB 3.7 is now available for both Core and Enterprise, landing alongside version 1.5 of the InfluxDB 3 Explorer UI. This release focuses on giving developers faster visibility into what their system is doing with one-click monitoring, a streamlined installation pathway, and broader updates that simplify day-to-day operations.

For more information, check out:

InfluxDB Docker latest tag changing to InfluxDB 3 Core

On February 3, 2026, the latest tag for InfluxDB Docker images will point to InfluxDB 3 Core. To avoid unexpected upgrades, use specific version tags in your Docker deployments.

If using Docker to install and run InfluxDB, the latest tag will point to InfluxDB 3 Core. To avoid unexpected upgrades, use specific version tags in your Docker deployments. For example, if using Docker to run InfluxDB v2, replace the latest version tag with a specific version tag in your Docker pull command–for example:

docker pull influxdb:2