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Karate Testing REST Service Response
‘$' represents the response. $ always refers to the JSON 'root', This can be used to frame a JSON Path and can be compared with the expected output using match operator.
JSONPath | Description |
$ | the root object/element |
@ | the current object/element |
. or [] | child operator |
.. | recursive descent. JSONPath borrows this syntax from E4X. |
* | wildcard. All objects/elements regardless their names. |
[] | subscript operator. XPath uses it to iterate over element collections and for predicates. In Javascript and JSON it is the native array operator. |
[,] | Union operator in XPath results in a combination of node sets. JSONPath allows alternate names or array indices as a set. |
[start:end:step] | array slice operator borrowed from ES4. |
?() | applies a filter (script) expression. |
() | script expression, using the underlying script engine. |
Fuzzy Matching
In the case where we don't know the exact value that is returned, we can still validate the value using markers — placeholders for matching fields in the response.
The supported markers are the following:
Marker | Description |
#ignore | Skip comparison for this field even if the data element or JSON key is present |
#null | Expects actual value to be null, and the data element or JSON key must be present |
#notnull | Expects actual value to be not-null |
#present | Actual value can be any type or even null, but the key must be present (only for JSON / XML, see below) |
#notpresent | Expects the key to be not present at all (only for JSON / XML, see below) |
#array | Expects actual value to be a JSON array |
#object | Expects actual value to be a JSON object |
#boolean | Expects actual value to be a boolean true or false |
#number | Expects actual value to be a number |
#string | Expects actual value to be a string |
#uuid | Expects actual (string) value to conform to the UUID format |
#regex STR | Expects actual (string) value to match the regular-expression 'STR' (see examples above) |
#? EXPR | Expects the JavaScript expression 'EXPR' to evaluate to true, see self-validation expressionsbelow |
#[NUM] EXPR | Advanced array validation, see schema validation |
#(EXPR) | For completeness, embedded expressions belong in this list as well |
Note that #present and #notpresent only make sense when you are matching within a JSON or XML context or using a JsonPath or XPath on the left-hand-side.
def json = { foo: 'bar' }
match json == { foo: '#present' }
match json.nope == '#notpresent'
The rest can also be used even in 'primitive' data matches like so:
match foo == '#string'
# convenient (and recommended) way to check for array length
match bar == '#[2]'
Optional Fields
If two cross-hatch # symbols are used as the prefix (for example: ##number), it means that the key is optional or that the value can be null.
def foo = { bar: 'baz' }
match foo == { bar: '#string', ban: '##string' }
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