Q6 of 40 · Karate

How do you parameterise a Karate scenario with multiple datasets?

KarateJuniorkaratescenario-outlineexamplesparameterized-testsbdd

Short answer

Short answer: Use Scenario Outline: with an Examples: table — column headers become variables available as <columnName> in steps. Karate runs the scenario once per row. For complex JSON payloads, use * def with call read and a JSON array instead — more flexible than table notation for nested objects.

Detail

Scenario Outline with Examples — best for scalar datasets:

Scenario Outline: Reject invalid emails
  Given path '/users'
  And   request { email: '<email>', name: 'Alice' }
  When  method POST
  Then  status 400
  And   match response.errors.email[0] == '<errorMsg>'

  Examples:
    | email          | errorMsg                    |
    |                | must not be blank           |
    | not-an-email   | must be a well-formed email |
    | @missing.local | must be a well-formed email |

Call read with JSON array — better for complex data:

* def cases = read('classpath:data/invalid-users.json')
* call read('classpath:helpers/create-user.feature') cases

Where invalid-users.json is [{ "email": "", "name": "Alice" }, ...]. Each element in the array drives one call to the feature.

When to prefer the JSON approach: the payload is a nested object, the column names would make the table unreadable, or the datasets are managed by non-engineers in a separate JSON file.

// EXAMPLE

validation-tests.feature

Feature: Input validation

  Background:
    * url 'https://api.example.com'

  Scenario Outline: Reject registrations with invalid email format
    Given path '/register'
    And   request { email: '<email>', password: 'Str0ngP@ss' }
    When  method POST
    Then  status 400
    And   match response.field   == 'email'
    And   match response.message == '<message>'

    Examples:
      | email            | message                     |
      |                  | must not be blank           |
      | not-an-email     | must be a well-formed email |
      | user@            | must be a well-formed email |
      | @example.com     | must be a well-formed email |

  # Report shows 4 separate scenario runs, one per row

// WHAT INTERVIEWERS LOOK FOR

Correct Scenario Outline + Examples syntax, knowing that <columnName> is the substitution syntax, and awareness of the call-with-array alternative for complex data. Each row producing an independent report entry is a quality signal.

// COMMON PITFALL

Using Scenario Outline for a complex nested JSON payload — the table quickly becomes unreadable. Use call read with a JSON array for anything beyond simple scalar substitutions.

// Related questions

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