docs-v2/content/flux/v0/spec/statements.md

title	description	menu	weight	aliases
Statements	Statements control execution in the Flux functional data scripting language.	flux_v0_ref parent name Flux specification Statements	112	/influxdb/v2/reference/flux/language/statements/ /influxdb/cloud/reference/flux/language/statements/

A statement controls execution.

Statement      = [ Attributes ] StatementInner .
StatementInner = OptionAssignment
                | BuiltinStatement
                | VariableAssignment
                | ReturnStatement
                | ExpressionStatement
                | TestcaseStatement .

Return statements

A terminating statement prevents execution of all statements that appear after it in the same block. A return statement is a terminating statement.

ReturnStatement = "return" Expression .

Expression statements

An expression statement is an expression where the computed value is discarded.

ExpressionStatement = Expression .

Examples of expression statements

1 + 1
f()
a

Testcase statements

A testcase statement defines a test case.

{{% note %}} Testcase statements only work within the context of a Flux development environment. {{% /note %}}

TestcaseStatement = "testcase" identifier [ TestcaseExtention ] Block .
TestcaseExtention = "extends" string_lit

Test cases are defined as a set of statements with special scoping rules. Each test case statement in a file is considered to be its own main package. In effect, all statements in package scope and all statements contained within the test case statement are flattened into a single main package and executed. Use the testing package from the standard library to control the pass failure of the test case.

Test extension augments an existing test case with more statements or attributes. A special function call, super(), must be made inside the body of a test case extension. All statements from the parent test case will be executed in its place.

Basic testcase for addition

import "testing"

testcase addition {
    testing.assertEqualValues(got: 1 + 1, want: 2)
}

Example testcase extension to prevent feature regression

@feature({vectorization: true})
testcase vector_addition extends "basics_test.addition" {
    super()
}

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