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Table of Contents

Structure

A MettleCI Unit Test Specification (often abbreviated ‘Spec’') is a YAML-formatted file which uses a grammar modelled loosely on the Gherkin syntax of a testing tool called Cucumber. The overall structure follows the Gherkin pattern…

Code Block
languageyaml
given:
  # This source of input data
when:
  # The specified job is executed with these parameter values
then:
  # Expect the Job to produce data that looks like this

Given

The given section defined a list of stage properties nodes (or sparseLookup nodes, see below) defining input links whose values you wish to replace with test data.

...

Each link is specified using a combination of stage and link properties (to uniquely identify an incoming link which supplies data to your Job) and a path property node to identify the test data CSV file containing the test data that is to be injected on that incoming link.

Sparse Lookup sources

When an input source is used with a Sparse Lookup stage then rather than using the stage node to specify the input you will use the sparseLookup node.

...

See this page for more information.

When

The when node specifies which job will be executed during testing as well as any parameters (including job macros) that affect the data produced by the job.

Code Block
languageyaml
when:
  job: KeyGeneratorExample                   # The DataStage Job with which this test spec is associated 
  parameters:
    DSJobStartDate: 2012-01-15               # Run the test using this value for the DSJobStartDate macro
    DSJobStartTime: 11:05:01                 # Run the test using this value for the DSJobStartTime macro 
    paramStartKey: 100                       # Run the test using this value for the paramStartKey Job parameter
    

Then

The then section associates unit test data files with each of your Job’s input links.

...

Similar to the Given section, each link in the Then section is specified using a combination of stage and link properties nodes (to uniquely identify an outgoing link which produces data from your Job) and a path property node to identify the test data CSV file containing the test data that is to be injected on that incoming link.

Cluster keys

The cluster property node is used to assist MettleCI’s resource management when using high volumes of test data. Setting a Cluster Key will prompt MettleCI to split the actual output and expected output using multiple, smaller subsets (based on the supplied keys) before the data is compared. Data is split such that each subset will only contain records that have the same values for all columns that make up the Cluster Key. In general, cluster keys should only be used when necessary rather then being , and not specified by default. Read more about the using the cluster property node in High Volume Unit Tests.

Row count comparisons

You can configure as test to only compare output row counts, rather than the content of those rows, by setting the checkRowCountOnly property node to true.

Code Block
languageyaml
then:
  - stage: Output
    link: Write1
    path: Output-Write1.csv
    checkRowCountOnly: true

See this page for more information.

Excluding columns from unit tests

You can omit selected columns from the output comparison by listing those columns them under an ignore property node for the relevant output.

Code Block
languageyaml
then:
  - stage: Transform
    link: Output
    path: Transform-Output.csv
    ignore: 
      - CREATION_DATE
      - LAST_UPDATED

See this page for more information.

Test Specification Types

Test SpecificationTest SpecificationDescription ? EmptyFail?Fail?

Job Run Mode

Test Specification

Description

‘Given’ section

'When' section

‘Then’ section

Normal

Ignored

Job is executed normally with no MettleCI no test harness intervention.

Unit Test Interception

✅ Specified

✅ Specified

✅ Specified

Interception is executed normally:

  • expected output is captured to the specified output files

  • source data references are irrelevant in this Job run mode.

∅ Unspecified

✅ Specified

✅ Specified

Sources are accessed without change and Job output is compared to specified Expected result.

⛔️ Specifies non-existent files

✅ Specified

✅ Specified

Causes test execution failure.

✅ Specified

✅ Specified

? Empty

∅ Unspecified

Causes test execution failure as there are no value Expected results to test against, so this is not a valid test.

✅ Specified

✅ Specified

⛔️ Specifies non-existent files

Re-baseline’s expected test output. See Capturing a Baseline Test Result.

Unit Test Execution

✅ Supplied

✅ Supplied

✅ Supplied⛔️ Empty

Test is executed normally.

∅ Unspecified

✅ Supplied

✅ Supplied

No input test data specified so the Job’s normal input operations are permitted to read from upstream data sources. Output is compared to an expected output test data file. See an example here.

⛔️ Specifies non-existent files

✅ Specified

✅ Specified

Test fails to execute and Job aborts.

✅ Supplied

✅ Supplied

⛔️ Empty∅ Unspecified

Input test data is injected into your jobs but no output test data is supplied for comparison so the Job’s normal output operations are permitted to write to downstream data stores. No output comparison is performed.

✅ Specified

✅ Specified

⛔️ Specifies non-existent files

Test fails to execute and Job aborts.

Test specification patterns

Include Page
Common Unit Testing Patterns
Common Unit Testing Patterns