Step 3: Creating tests

🧪 Step 3: End-to-End Testing for Bank Holidays Service

The Variant platform provides a flexible way to test entire API flows using the built-in test runner. Here, we demonstrate three full integration tests covering:

• Valid region responses

• Date-specific logic

• Error handling for invalid inputs

These tests are defined declaratively using Y# in your !Main.yaml file and executed via the /api/integrationtests endpoint.

---

✅ Test 1: Valid Region Requests

This test ensures that calling GET /api/bankholidays/{region}:

• Returns the correct region

• Includes the expected number of holiday events

- pipe: Variant.TestRunner.Default.RunTests
  TEST_NAME_PREFIX: GET_api_bankholidays_
  TEST_DATA: |-
    | TestName | Region             | Count |
    | england  | england-and-wales  | 75    |
    | scotland | scotland           | 84    |
    | ni       | northern-ireland   | 93    |
  DEFAULTS_ADDITIONAL_ROW_INFO:
    HostUrl: ${Request.Header.Scheme}://${Request.Header.Host}
  ACT_PIPES:
    - pipe: _CallService
      HTTP_URL: ${Defaults.Additional.HostUrl}/api/bankholidays/${Defaults.Region}
      HTTP_METHOD: GET
      HTTP_READ_AS: JToken
  ASSERTION_PIPES:
    - pipe: Variant.TestRunner.Default.Assert
      ASSERT_EXPRESSION: >-
        "${Response.region}" == "${Defaults.Region}" &&
        ${Response.events.Count()} == ${Defaults.Count}

---

✅ Test 2: Bank Holiday Date Check

This test targets the GET /api/bankholidays/{region}/{date} endpoint to:

• Check whether a specific date is or is not a bank holiday

• Validate correct content type returned

- pipe: Variant.TestRunner.Default.RunTests
  TEST_NAME_PREFIX: GET_api_bankholidays_date_
  TEST_DATA: |-
    | TestName         | Region             | Date       | Result |
    | IsBankHoliday    | england-and-wales  | 2019-01-01 | True   |
    | IsNotBankHoliday | england-and-wales  | 2019-01-03 | False  |
  DEFAULTS_ADDITIONAL_ROW_INFO:
    HostUrl: ${Request.Header.Scheme}://${Request.Header.Host}
  ACT_PIPES:
    - pipe: _CallService
      HTTP_URL: ${Defaults.Additional.HostUrl}/api/bankholidays/${Defaults.Region}/${Defaults.Date}
      HTTP_METHOD: GET
      HTTP_READ_AS: JToken
  ASSERTION_PIPES:
    - pipe: Variant.TestRunner.Default.Assert
      ASSERT_EXPRESSION: >-
        "${Response.isBankHoliday.ToString()}" == "${Defaults.Result}" &&
        "${ResponseContentHeaders.Content-Type}" == "application/json"

---

✅ Test 3: Input Validation & Error Handling

This test covers failure scenarios such as:

• Invalid region names (e.g. xyz)

• Improperly formatted dates (e.g. 201901-03)

Using RunExceptionTests, we validate that the service:

• Returns the appropriate HTTP status code

• Returns the correct error message

- pipe: Variant.TestRunner.Default.RunExceptionTests
  EXCEPTION_TEST_NS: TestException
  TEST_NAME_PREFIX: Exceptions_
  TEST_DATA: |-
    | TestName      | Region             | Date       | ErrorText           | StatusCode |
    | InvalidRegion | xyz                | 2019-01-01 | Invalid region: xyz | 400        |
    | InvalidDate   | england-and-wales  | 201901-03  | Invalid date format | 400        |
  DEFAULTS_ADDITIONAL_ROW_INFO:
    HostUrl: ${Request.Header.Scheme}://${Request.Header.Host}
  ACT_PIPES:
    - pipe: _CallService
      HTTP_URL: ${Defaults.Additional.HostUrl}/api/bankholidays/${Defaults.Region}/${Defaults.Date}
      HTTP_METHOD: GET
      HTTP_READ_AS: String
  ASSERTION_PIPES:
    - pipe: Variant.TestRunner.Default.Assert
      ASSERT_EXPRESSION: >-
        "${TestException.ErrorText}" == "${Defaults.ErrorText}" &&
        ${TestException.OutcomeId} == ${Defaults.StatusCode}

---

These tests provide full confidence in both the functional correctness and robustness of your service.

✅ Summary

With Variant’s built-in test runner, you can:

• Define tests using declarative Y#

• Run them via a dedicated /api/integrationtests endpoint

• Test single logic units or full API pipelines

• Store test results in Azure Tables (automatically handled)

This structured testing approach promotes TDD and keeps services robust and production-ready.