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Tester

Evaluates one or more tests on a feature, and routes the feature according to the outcome of the test(s).

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Typical Uses

  • Performing quality testing on data
  • Dividing features into two streams based on a test
  • Isolating a subset of features based on a test

How does it work?

The Tester accepts any feature. It evaluates each feature against one or more user-defined tests, and outputs the feature via the Passed port if it meets the defined conditions, or via the Failed port if it fails the defined conditions.

The tests are constructed as a series of Test Clauses, which evaluate values or expressions based on a wide range of available Operators and test types. The Test Clauses are connected with Logic - combinations of AND, OR, and NOT, with parentheses to define evaluation order.

Creating Test Clauses

Each clause is composed of a value to test, and the method of testing it. Depending on the type of test, at a minimum the clause will consist of a Left Value and an Operator. If the chosen Operator needs more information (for example, testing for an attribute that is greater than a certain value), a Right Value field is provided.

The Test Clauses are created in a table, and numbered from the top down.

Left Value

Operator

Right Value

Mode*
The value or expression to test The type of test to perform The value for comparison, if required by the operator Test the values in a specific manner
Examples
Latitude > 49.000001 Automatic
@Area() In Range (1,100) Numeric
SnackType Like Kebabs Case Sensitive
Traffic Attribute Is Null <Unused> Automatic
Count Type Is Integer Automatic

* Note that Mode is only available for individual tests when Comparison Mode is set to Specify Per Test.

ClosedTest Clause Operators

These are the Operators available for constructing test clauses. They may be used to test attribute values, constructed expressions, constants, and published parameters.

Operator

Description

Right Value Configuration
= Equal to Enter a value for comparison.
!= Not Equal to Enter a value for comparison.
< Less than Enter a value for comparison.
> Greater than Enter a value for comparison.
<= Less than or equal to Enter a value for comparison.
>= Greater than or equal to Enter a value for comparison.
In Range

Tests if the value falls within the numeric range specified in set notation.

Open-ended ranges may be defined by leaving either the lower or upper limit blank.

Range values are separated by a comma and enclosed by brackets.

Square brackets - [ ] - indicate inclusive limits (greater than or equal to, less than or equal to).

Round brackets - ( ) - indicate exclusive limits (greater than, less than).

Valid range examples:

(1,9) Greater than 1 and less than 9

[1,9] Greater than or equal to 1 and less than or equal to 9

(1,9] Greater than 1 and less than or equal to 9

(1,) Greater than 1

[,9] Less than or equal to 9

Note: This operator is not available when Mode is set to Case Sensitive or Case Insensitive, and those modes are not available when the operator is set to In Range.

In Tests if the value may be found in the provided list of possible values and ranges.

Enter any combination of comma-separated strings, numeric values, and/or ranges (in the form of x-y).

Valid configuration examples:

1,10,100

1-99

cat

cat,dog,cats and dogs

dogs,1-9,7

Note: String ranges (for example, a-d) can also be specified. To test for values that contain a hyphen, enclose the value in quotation marks: "LL-27","LL-83"
Like Tests that the value matches a specified string pattern.

Enter a string pattern. Wildcards are supported using the percentage symbol (%), rather than an asterisk (*).

In Automatic mode, this operator is case insensitive. This operator is not available when Mode is set to Numeric.

Example:

If Right Value is %bc%:

abcd: Passed

bc: Failed

Contains Tests that the Right Value occurs somewhere in the Left Value.

Enter a value to test for.

In Automatic mode, this operator is case insensitive. This operator is not available in Numeric mode.

Example:

If Right Value is bc:

abcd: Passed

abde: Failed

Begins With Tests that the Left Value string begins with the Right Value string.

Enter the string to be tested against.

In Automatic mode, this operator is case insensitive. This operator is not available in Numeric mode.

Example:

If Right Value is Do:

Dogs: Passed

Cats: Failed

Ends With Tests that the Left Value string ends with the Right Value string.

Enter the string to be tested against.

In Automatic mode, this operator is case insensitive. This operator is not available in Numeric mode.

Example:

If Right Value is gs:

Dogs: Passed

Cats: Failed

Contains Regex Tests that the value contains a string that matches a pattern described by a Regular Expression.

Enter a Regular Expression.

The Regular Expression Editor is available via the ellipsis (...) button, and may be used to construct and test expressions.

The regex to test may represent a string to be found anywhere within the value, or may represent the entire value (by creating a regex long enough to represent the extent of the desired value).

Example:

If regex is \d (Any digit)

cats: Failed

9: Passed

cats82: Passed

Type Is

Tests if the value is compatible with the chosen Type.

You may test for multiple types by adding additional Test Clauses.

Select the Type to test for.

Boolean Valid Boolean values are the strings TRUE, True, true, 1, FALSE, False, false, 0.
Double Floating point number
Integer Integer
Numeric A number (same behavior as Double)
Alphanumeric All characters are either a digit (0-9) or a letter (a-z, A-Z). White space, nulls, control codes, punctuation, and accented or extended characters are not included.
String A sequence of characters. The value is not null or missing, and does not contain any null characters.
XML Checks for valid XML syntax.
JSON Checks for valid JSON syntax.
Encodable In Tests if the value is encodable in the specified encoding without data loss.

Select from a list of standard encodings.

Sample encodings:

  • Unicode 32-bit(utf-32)
  • Windows Cyrillic (windows-12510
  • EBCDIC US (ibm037)
Attribute has a value Tests that the attribute has a value, and is not null, missing, or empty. <Unused>
Attribute Is Null Tests that the attribute has a null value.

<Unused>

Attribute is Empty String Tests that the value is an empty string. <Unused>
Attribute is Missing Tests that the attribute is absent on the feature <Unused>

Connecting Test Clauses: Logic

Multiple test clauses are connected with Logic, using AND, OR, and NOT in addition to parentheses to specify how the tests are evaluated to determine passing or failing.

Logic connectors can be edited by selecting options in the Logic column of the Test Clauses table, or may be edited directly using the Composite Expression parameter’s Edit button.

ClosedExample: Simple test for the existence of a value

In this example, we start with a dataset of food trucks, and want to identify any records that are missing a Business Name.

The features are routed into a Tester.

In the parameters dialog, we configure one test. The Left Value is set to the BUSINESS_NAME attribute, and the Operator is set to Attribute has a value.

As there is only one test, the Pass Criteria (AND/OR/Composite) is not relevant.

No Right Value is required, as the test is simply looking for the existence of any value.

Features that fail the test are output via the Failed port, and can be sent for further processing elsewhere.

ClosedExample: Testing for multiple choices with OR

In this example, we start with a dataset of food trucks, and wish to test for those that are serving Mexican food. The features are routed into a Tester.

In the parameters dialog, we construct two tests, both using the DESCRIPTION attribute as the Left Value.

The first test looks for an exact match - any feature where the DESCRIPTION is Mexican Cuisine. The second test is less strict - it looks for any values that begin with Tacos.

The Logic connector is set OR - meaning any feature that matches either of these tests will be output via the Passed port.

Comparison Mode is set to Case Insensitive, which will apply to both test clauses.

Four features match at least one of the tests.

ClosedExample: Composite test criteria

In this example, we start with a dataset of city parks. We will test them to find dog parks of a certain minimum size, in two specific neighborhoods. The features are routed into a Tester.

In the parameters dialog, we add four individual test clauses:

  • Dog Park: Y
  • Area is greater than 40000 ( square meters, in ground units - using the @Area() function to evaluate the geometry)
  • Neighborhood Name is Strathcona
  • Neighborhood Name is Fairview

As we have two choices of neighborhood name, we use a Composite Expression to describe the test conditions we want:

  • 1 AND 2 AND (3 OR 4) means (note that the numbers indicate the row number of the test clause):
    • It must be a dog park (rule 1), AND;
    • It must be greater than 40,000 m2 (rule 2), AND;
    • It must be in either the Strathcona (rule 3) OR Fairview (rule 4) neighborhood.

    The Logic connectors and parentheses can be selected in the Logic column, or entered directly using the Edit button.

Two parks meet the criteria.

Usage Notes

  • Due to bulk mode processing, features may appear to output in chunks. Although feature order from a single output port remains intact, when chunks of features are output through both the Passed and Failed ports, unexpected results may occur in workspaces that rely on feature ordering from joined output ports. In these scenarios, we recommend that you do not upgrade the Tester to its 2019.1 or later version, or revise your workspaces so they do not rely on feature ordering from joined output ports.
  • If you have several Tester transformers in sequence, consider using the TestFilter instead. This transformer allows you to create a series of tests with named output ports for each result.
  • When filtering out a subset of features, consider the logic of the test(s) when choosing an output port. For example, to remove all of the Dog Parks from a list of parks, you could either:
    • Set DogParks=Y, and connect the Failed port (dropping the Passed features), or
    • Set DogParks=N, and connect the Passed port (dropping the Failed features).

Configuration

Input Ports

ClosedInput

Features to be tested.

Output Ports

ClosedPassed

If the feature passes according to the test configuration, it is output via the Passed port.

ClosedFailed

If the feature fails according to the test configuration, the feature is output via the Failed port.

Parameters

ClosedTest Clauses

See Creating Test Clauses above for further detail.

Logic

Determines how clauses are evaluated in a composite test.

Note that changes made using the Composite Expression parameter’s Edit function will be reflected in this column once they have been Applied, including the placement of parentheses.

OR Flexible inclusion: one of the test conditions must be met.
AND Inclusion: the following test condition must be met.
NOT Exclusion: the following test condition must not be met.
Parentheses Used to construct composite expressions, specifying order of clause evaluation.
Left Value

The Left Value may be the value of an attribute, expression, a literal constant, a published parameter or a calculated value that is a combination of the above.

If it is a calculated function or expression, it will be executed for each feature and the result will be used for the test.

Operator

Select the type of test to be performed. Options include:

  • = (Equal to)
  • != (Not equal to)
  • < (Less than)
  • > (Greater than)
  • <= (Less than or equal to)
  • >= (Greater than or equal to)
  • In Range
  • In
  • Like
  • Contains
  • Begins With
  • Ends With
  • Contains Regex

  • Type Is

    • Boolean

    • Double

    • Integer

    • Numeric

    • Alphanumeric

    • String

    • XML

    • JSON

  • Encodable In

  • Attribute has a value

  • Attribute is Null

  • Attribute is Empty String

  • Attribute is Missing
Right Value

Enter any required comparison values or supplementary configuration information for the test selected.

Depending on the Operator chosen, a drop-down list of choices or an ellipses button accessing an additional dialog with correct parameters may become available, to assist in entering values.

Mode

If required, specify a method for evaluating values.

This column is only available when Comparison Mode is set to Specify Per Test.

See Comparison Mode below for available options.

Comparison Mode

Specify a method for evaluating values.

This choice will be applied to all tests, unless Specify Per Test is selected, enabling the Mode column in the Test Clauses table.

Automatic Compares values as numbers if possible, and strings otherwise.
Numeric Compares values as numbers if possible, and strings otherwise.
Case Sensitive Compares values as strings using a case sensitive comparison, and will not attempt numeric conversions.
Case Insensitive Compares values as strings using a case insensitive comparison, and will not attempt numeric conversions.
Date/Time

Compares values as FME Date/Time values if possible.

It can use different mathematical operators such as = (are the two dates the same) or > (is the first date newer than the second).

If the input data is not in FME Date format, the comparison will be done as string and an attribute, fme_expression_warnings{} will be added to the feature to indicate this was done.

Example: if Mode is set to Date/Time, “20180109141824.9024787-08:00=20180109131824.9024787-09:00” will pass the test.

Specify Per Test Enables the Mode column, where individual comparison mode selections may be made.
  • For a string that can be represented as a number such as 4.5 or 4e5, if you set Mode to Automatic or Numeric, it will be treated as a number if the comparison value is also representable as a number.
  • For example, if Mode is set to Automatic or Numeric, “4E5=400000” will pass the test. If, on the other hand, you want “4E5=400000” to fail the test, set Mode to Case Sensitive or Case Insensitive.

Tip: If you know your data is string data, you should set the mode to either Case Sensitive or Case Insensitive. This way, FME does not spend time for each feature to determine if the data is representable as a number, but can just do the string comparison immediately.
Composite Expression

Enabled when multiple test clauses are created.

Enter or edit a test expression that defines the criteria to met in order for a feature to be considered Passed. If edits are made here, the changes will be reflected in the Test Clauses table’s Logic column once the Apply button is used to save changes. Inversely, changes made by selecting Logic options will be reflected here.

Test Clauses are referred to by their number, in the order listed in the Test Clauses table. Clauses may be joined by AND, OR, and NOT, with parentheses.

Example:

((1 AND 2) OR 3)

Interpretation: Clause 1 AND Clause 2 must be true, OR Clause 3 must be true.

See the Composite example above for a use case.

When doing comparisons, null, missing, and empty string values, all evaluate to empty string. Thus, they are considered equal in the context of the comparison operators. Further, the following comparison ordering is respected:

  • Null, missing, empty string < other values

In Automatic mode, all operators are case sensitive except Like, Contains, Begins With, and Ends With.

Editing Transformer Parameters

Using a set of menu options, transformer parameters can be assigned by referencing other elements in the workspace. More advanced functions, such as an advanced editor and an arithmetic editor, are also available in some transformers. To access a menu of these options, click beside the applicable parameter. For more information, see Transformer Parameter Menu Options.

Defining Values

There are several ways to define a value for use in a Transformer. The simplest is to simply type in a value or string, which can include functions of various types such as attribute references, math and string functions, and workspace parameters. There are a number of tools and shortcuts that can assist in constructing values, generally available from the drop-down context menu adjacent to the value field.

ClosedHow to Set Parameter Values

Using the Text Editor

The Text Editor provides a convenient way to construct text strings (including regular expressions) from various data sources, such as attributes, parameters, and constants, where the result is used directly inside a parameter.

Text Editor

Using the Arithmetic Editor

The Arithmetic Editor provides a convenient way to construct math expressions from various data sources, such as attributes, parameters, and feature functions, where the result is used directly inside a parameter.

Arithmetic Editor

Conditional Values

Set values depending on one or more test conditions that either pass or fail.

Parameter Condition Definition Dialog

Content

Expressions and strings can include a number of functions, characters, parameters, and more - whether entered directly in a parameter or constructed using one of the editors.

ClosedContent Types

String Functions

These functions manipulate and format strings.

Special Characters

A set of control characters is available in the Text Editor.

Math Functions

Math functions are available in both editors.

Math Operators

These operators are available in the Arithmetic Editor.

FME Feature Functions

These return primarily feature-specific values.

FME Parameters

FME and workspace-specific parameters may be used.
Working with User Parameters Create your own editable parameters.

Reference

ClosedRelated Transformers

AttributeFilter

AttributeRangeFilter

AttributeValidator

GeometryValidator

JSONValidator

TestFilter

XMLValidator

Processing Behavior

Feature-Based

Feature Holding

No
Dependencies None
FME Licensing Level FME Base Edition and above
Aliases
History This transformer replaced the AttributeTester and GenericTester transformers.
Categories

Data Quality

Filters and Joins

FME Community

The FME Community is the place for demos, how-tos, articles, FAQs, and more. Get answers to your questions, learn from other users, and suggest, vote, and comment on new features.

Search for all results about the Tester on the FME Community.

 

Examples may contain information licensed under the Open Government Licence – Vancouver