The basics of test assertion

Test assertion is implemented using XPath 1.0 and Truugo function library.

Pseudo-code presentation of a basic assertion:

TARGET

Specifies the structure(s) to which a test assertion applies. The target must be an XML element or a list of XML elements. You can use pipe sign "|" to specify multiple targets for a test assertion. To setup a test assertion for XML attribute, use its parent element as a target: /Path/To/Element[@attributeX]

PRECONDITION (optional)

Can be used to apply a test assertion to certain target structure(s) or use case(s) only. If given, the predicate will be evaluated only when the precondition evaluates to true (boolean).

PREDICATE

Specifies the test for the target structure(s).

NOTICE

Descriptive (error) notice which is returned when the predicate test evaluates to false (boolean). You can use XPath function concat() to combine static and dynamic text to the notice.

In order to implement more complex assertions, you may need to add some extra ingredients to a basic assertion:

Pseudo-code presentation of an advanced assertion:

NAMESPACE PREFIX

Instead of using a namespace URI in your test assertions:

/my:very:long:namespace:uri:Order

You can define a namespace prefix, such as "doc", to keep XPath expressions shorter (more sensible):

/doc:Order

GLOBAL VARIABLE

A global variable is defined once per a test profile and can be reused in test assertions.

It is used mainly for the following purposes:

• to setup a switch between loose and strict validation to decide assertions to be executed
• to specify the use case based on the message data to decide assertions to be executed
• to perform validation against an external data file (which is read into a variable)

LOCAL VARIABLE

A local variable is not just assertion-specific, it is specified per each target item. The value of a local variable is set within a target loop and thus it can be used as a part of the following expressions: Precondition, Predicate, Notice.

It is used mainly for the following purposes:

• to split complex logic to sensible parts
• to reuse calculated values, primarily in Predicate and Notice expressions
• to use an item value as a filter (within square brackets) in an expression

Truugo transforms EDIFACT messages into XML syntax using the following naming principles:

MESSAGE ROOT

Tag <INVOIC> for the message type INVOIC (UNH.S009.0065)

SEGMENT GROUP

Tag <GRP2> for the segment group 2

SEGMENT

Tag <NAD> for the segment NAD

COMPOSITE

Tag <C082> for the composite C082

ELEMENT

Tag <e3035> for the element 3035

XPath examples

XPath expression to refer to all party identifiers on a header level:

XPath expression to refer to all party identifiers on a header and a line level (see the pipe sign):

XPath expression to refer to all party identifiers in a message:

XPath expression to refer to the buyer's party identifier only (using a filter):

Truugo transforms EDIFACT messages to XML syntax before running the validation.

Original EDIFACT message:

After the EDIFACT-to-XML transformation:

Truugo function library makes it easier to implement complex assertions:

Boolean

Functions for checking whether a given value is valid
Examples: validIBAN(), validCountryCode(), validPattern()

Math

Functions for counting or calculating values
Examples: countSum(), countDistinctValues(), countDaysFromNow()

Misc

Special support functions to ease assertion implementation
Example: IfThenElse()

Output

Function for formatting an error notice
Examples: getPath(), getLineNumber(), formatNumber()

The notation for using Truugo functions:

An example of how to check that a CountryCode element contains a valid 2-letter ISO country code: