Improving Assert Error for a given textual body

[fabricereix]

Response body can be tested directly without explicit asserts as follow:

test.hurl
1  GET http://example.com/text
2  HTTP/1.1 200
3  ```
4  one
5  two
6  three
7  ```

If the server returns the following response

one 
to
three

the following error will be produced:

error: Assert Body Value
  --> test.hurl:4:1
   |
 4 | one
   | ^ actual value is <one
   |   to
   |   three>

Instead of taking into account the full multiline body, we could focus on the first line that differs.

The previous errors would become:

error: Assert Body Value
  --> test.hurl:5:1
   |
 5 | two
   | ^ actual value is <to>
   |   

This fits quite well with the line-oriented structure of hurl files.

Testing json output can also be a good example.

test.hurl
1  GET http://example.com/json
2  HTTP/1.1 200
3  {
4     "name": "Bob",
5     "age": 32
6  }

If the server returns the following response

{
   "name": "Bob",
   "age": 30
}

The following error will be produced:

error: Assert Body Value
  --> test.hurl:3:1
  |
3 | {
  | ^ actual value is <{
  |       "user": "Bob"
  |       "age": "30"
  |   }>

Taking into account only the first line in error, we get the following error instead:

error: Assert Body Value
  --> test.hurl:5:1
   |
 5 |    "age": 32
   |  ^ actual value is <    "age": 30>
   |   

We could even position the error at the exact different chracter

error: Assert Body Value
  --> test.hurl:5:12
   |
 5 |    "age": 32
   |            ^ actual value is <0>
   |