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String Interpolation

Since v1.0.0

It is often useful to reference settings, captured values and other text throughout your feature and meta files. To support this, Gwen provides a placholder substitution mechanism.

Placeholder Syntax​

Placeholders are declared using the ${placholder} syntax and can include:

  • An environment variable name (since gwen-web 2.36.0)
    • example: ${env.USER} for the USER variable
  • A system property name
  • A Gwen setting name
  • A named binding in the currently accessible scope
  • JS arrow functions

Examples​

Interpolation by Substitution​

Substitution involves replacing named placeholders with their values.

 Feature: String Interpolation

Scenario: By Substitution
    
    Given my mechanism is "substitution"
      And my value is "${my.property}"
      And my proposition is "By ${my mechanism}, my value will be ${my value}"
     Then my proposition should be "By substitution, my value will be ${my.property}"

Interpolation by Concatenation​

Deprecated

The concatentation method has been deprecated in favor of substitition since Gwen 3 (dropped in v3.14.0)

Concatenation involves joining string literals and named values together.

 Feature: String Interpolation

Scenario: By Concatenation
    
    Given my mechanism is "concatenation"
      And my value is "" + my.property
      And my proposition is "By " + my mechanism + ", my value will be " + my value
     Then my proposition should be "By concatenation, my value will be " + my.property