---
title: testing.run() function
description: >
  `testing.run()` executes a specified test case.
menu:
  flux_0_x_ref:
    name: testing.run
    parent: testing
    identifier: testing/run
weight: 101

introduced: 0.20.0
---

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`testing.run()` executes a specified test case.



##### Function type signature

```js
(case: () => {A with want: stream[C], input: B, fn: (<-: B) => stream[C]}) => stream[{C with _diff: string}] where C: Record
```

{{% caption %}}For more information, see [Function type signatures](/flux/v0.x/function-type-signatures/).{{% /caption %}}

## Parameters

### case
({{< req >}})
Test case to run.




## Examples

### Define and execute a test case

```js
import "csv"
import "testing"

inData =
    "
#datatype,string,long,string,dateTime:RFC3339,string,double
#group,false,false,true,false,true,false
#default,_result,,,,,
,result,table,_measurement,_time,_field,_value
,,0,m,2021-01-01T00:00:00Z,t,1.2
,,0,m,2021-01-02T00:00:00Z,t,1.4
,,0,m,2021-01-03T00:00:00Z,t,2.2
"

outData =
    "
#datatype,string,long,dateTime:RFC3339,dateTime:RFC3339,string,string,double
#group,false,false,true,true,true,true,false
#default,_result,,,,,,
,result,table,_start,_stop,_measurement,_field,_value
,,0,2021-01-01T00:00:00Z,2021-01-03T01:00:00Z,m,t,4.8
"

t_sum = (table=<-) =>
    table
        |> range(start: 2021-01-01T00:00:00Z, stop: 2021-01-03T01:00:00Z)
        |> sum()

test _sum = () => ({input: csv.from(csv: inData), want: csv.from(csv: outData), fn: t_sum})

testing.run(case: _sum)
```