Custom Assertions in Robonito

Custom Assertions allow you to validate UI text dynamically using runtime variables instead of fixed, hardcoded strings.

This approach is essential for scaling automation when expected values change fluidly during execution. Typical scenarios include validating:

  • Dynamically generated Order IDs or Usernames.
  • Live timestamps.
  • API-generated content injected into the UI.
  • Form data entered during preceding test steps.

The Power of Custom Assertions

Traditional static assertions verify hardcoded text, which makes tests highly brittle:

  • Static Assertion: Expects the UI to say exactly "Welcome, Arshad". (This test will fail the moment User B logs in).

Custom Assertions solve this by evaluating against a dynamic memory variable:

  • Custom Assertion: Expects the UI to say "Welcome, {{!username}}". (This test passes for any user, making the test suite infinitely reusable).

Variable Syntax Rules

To reference a dynamically cached variable during a UI assertion, you must use double-curly braces prefixed with an exclamation mark:

Syntax:
{{!variable_name}}

Examples:

  • {{!page_title}}
  • {{!current_user}}
  • {{!generated_order_id}}

During test execution, Robonito safely intercepts these placeholders and injects the actual runtime value stored in memory before performing the text comparison.

Step-by-Step Implementation

Step 1: Capture the Dynamic Value

Before you can assert against a variable, you must store it in memory. You can capture variables by:

  • Recording a Local Variable directly from an onscreen UI element.
  • Saving a user configuration from an Input step.
  • Extracting a payload using an API Variable.

Example: You capture a generated ID and save it as: order_id = "ORD-999".

Step 2: Configure the Assertion

  1. Open the Add Assertion dialogue in Robonito.
  2. Select Content Based → Custom Expression.
  3. In the Expected Value field, inject your variable using the exact syntax:
    Wait for your order: {{!order_id}}

Step 3: Execution Behavior

During runtime, Robonito processes the test logically:

  1. Translates {{!order_id}} into "ORD-999".
  2. Scans the target UI element.
  3. If the UI says "Wait for your order: ORD-999", the assertion logs a ✅ PASS.

Essential Rules

  • Pre-requisite Existence: The variable must be initialized and stored in a test step before the assertion step occurs chronologically.
  • Strict Case Sensitivity: Variable names inside the brackets ({{!varName}}) are strictly case-sensitive.
  • The Exclamation Formatting: You MUST include the ! prefix inside the curly braces to trigger runtime resolution.