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String Interpolation

Since v1.0.0

String interpolation 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​

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}"

Elvis Operator​

Since v4.4.0

The elvis ?: syntax can be used to define default values for references which may not exist

Examples​

 Given a is "${some.string :? 'default'}"
   And b is "${some.string :? '${some.other.string}'}"
   And c is "${some.string :? blank}"
   And d is "${some.boolean :? false}"
   And e is "${some.string1 :? '${some.string2 ?: blank}'}"
  • Set a to value bound to some.string or to default string value if undefined
  • Set b to value bound to some.string or to value bound to some.other.string if undefined
  • Set c to value bound to some.string or to a blank string value if undefined:
  • Set d to value bound to some.string or to a false Boolean value if undefined:
  • Set e to value bound to some.string1 or value bound to some.string2 if undefined, or to a blank string value if both are undefined: