[DOCS-13406] Add guide for conditional logic in Synthetic tests

content/en/synthetics/guide/_index.md

@@ -37,6 +37,7 @@ cascade:
     {{< nextlink href="synthetics/guide/synthetic-tests-caching" >}}Avoid cache issues in Synthetic tests{{< /nextlink >}}
     {{< nextlink href="synthetics/guide/monitor-https-redirection" >}}Monitor your HTTP requests are redirected into HTTPS{{< /nextlink >}}
     {{< nextlink href="synthetics/guide/reusing-browser-test-journeys/" >}}Reuse browser tests journeys across your test suite{{< /nextlink >}}
+    {{< nextlink href="synthetics/guide/conditional-logic-subtests/" >}}Implement conditional logic in Synthetic tests{{< /nextlink >}}
     {{< nextlink href="synthetics/guide/custom-javascript-assertion/" >}}Use custom JavaScript assertions in browser tests{{< /nextlink >}}
     {{< nextlink href="synthetics/guide/email-validation/" >}}Use email validation in browser tests{{< /nextlink >}}
     {{< nextlink href="synthetics/guide/testing-file-upload-and-download/" >}}Upload and download test files{{< /nextlink >}}

content/en/synthetics/guide/conditional-logic-subtests.md

@@ -0,0 +1,98 @@
+---
+title: Implement Conditional Logic in Synthetic Tests
+further_reading:
+    - link: '/synthetics/browser_tests/advanced_options'
+      tag: 'Documentation'
+      text: 'Configure Advanced Options for Browser Test Steps'
+    - link: '/synthetics/browser_tests/test_steps#subtests'
+      tag: 'Documentation'
+      text: 'Browser Test Steps'
+    - link: '/synthetics/multistep'
+      tag: 'Documentation'
+      text: 'Multistep API Tests'
+products:
+- name: Browser Tests
+  url: /synthetics/browser_tests/
+  icon: browser
+- name: Multistep API Tests
+  url: /synthetics/multistep/
+  icon: synthetics
+- name: Mobile App Testing
+  url: /synthetics/mobile_app_testing/
+  icon: mobile
+---
+
+{{< product-availability >}}
+
+## Overview
+
+Conditional branching allows your Synthetic Monitoring tests to adapt to different application states and execute different paths based on runtime conditions. Instead of following a single linear sequence, a test can decide which steps to run, skip, or continue after failures.
+
+This guide covers three use cases for conditional branching. Each use case applies one or more of these step execution options:
+- If this step fails, continue to next step
+- If this step succeeds, stop this test and mark it as passed
+- Always run this step
+
+## Run different test paths based on application state
+
+Use this pattern when your application can show different UI states, such as in A/B tests, and you want a single test that executes different steps depending on which state it encounters.
+
+**Example logic:**
+- If journey A header is found, run journey A steps
+- Else, if journey B header is found, run journey B steps
+
+To set up this pattern:
+
+1. Create a subtest that represents journey A:
+   - Add a step that checks for the journey A element (for example, a step that asserts or clicks on a journey A header). 
+   - Add the remaining journey A steps inside that subtest.
+2. In the subtest's advanced options, enable the following:
+   - **If this step fails, continue to next step**: Prevents a failure from stopping the entire test.
+   - **If this step succeeds, stop this test and mark it as passed**: Ends the test and does not run the other journey when journey A is found.
+4. Add a second subtest for journey B: a step that checks for the journey B element, followed by the journey B steps.
+5. Enable **If this step fails, continue to next step** on the journey B subtest.
+6. Order the subtests so the test runs journey A first, then journey B. Whichever condition matches runs to completion; the other subtest fails silently and the test continues.
+
+{{< img src="synthetics/guide/conditional_logic/subtests.png" alt="Subtest configuration showing if/else step execution options" style="width:60%;" >}}
+
+For more information on subtest configuration options, see [Subtests][1].
+
+## Interact with the first available element
+
+Use this pattern when you need to interact with the first available option, such as selecting an in-stock product size or the first available item in a list.
+
+**Example logic:**
+- If product A is available, proceed to purchase
+- Else, if product B is available, proceed with product B
+- Else, skip to the next available product
+
+To set up this pattern:
+
+1. Add a step that interacts with the target element (for example, clicking an **add to cart** button or selecting a size from a **select a size** dropdown).
+2. In the step's advanced options, set a **User Specified Locator** using XPath or CSS that targets only available elements (for example, `.size.available` or a class that indicates in-stock status).
+3. Enable **If this step fails, continue to next step** so the test continues if no matching element is found.
+4. Add a follow-up step or subtest that tries the next option (for example, a different size or product).
+5. If the UI has filters or search, add steps that narrow the page to available items first so the locator targets only the correct elements.
+
+{{< img src="synthetics/guide/conditional_logic/if_this_step_fails.png" alt="Step advanced options showing User Specified Locator and allow failure settings" style="width:60%;" >}}
+
+## Always run specific steps
+
+Use this pattern when certain steps must always run regardless of earlier results, such as logging out, releasing resources, or capturing error state.
+
+To set up this pattern:
+
+1. Add a subtest at the end of your test that contains only the cleanup or teardown steps.
+2. In the subtest's advanced options, enable **Always run this step**.
+3. Save the test. The cleanup subtest runs even when earlier steps have failed.
+
+{{< img src="synthetics/guide/conditional_logic/always_run_step.png" alt="Subtest advanced options with Always run this step enabled" style="width:60%;" >}}
+
+For more information, see [Set execution behavior][2].
+
+## Further reading
+
+{{< partial name="whats-next/whats-next.html" >}}
+
+[1]: /synthetics/browser_tests/advanced_options#subtests
+[2]: /synthetics/browser_tests/advanced_options#set-execution-behavior