Replace github.com/yalp/jsonpath with github.com/PaesslerAG/jsonpath

[sjlee]

Fix #48.

It replaces the github.com/yalp/jsonpath dependency which does not have a license with github.com/PaesslerAG/jsonpath.

[coveralls]

Coverage remained the same at 97.198% when pulling 5dc8e9f on sjlee:jsonpath into c44a6d7 on gavv:master.

[gavv]

Thanks. LGTM, but I think I need to test it a bit before merging to ensure that we don't break compatibility.

[sjlee]

Thanks. Absolutely.

[gavv]

Hi, sorry for delay.

I've added some tests for jsonpath (based on original yalp/jsonpath tests):
https://github.com/gavv/httpexpect/blob/master/value_test.go#L417

Unfortunately, this small PR breaks the compatibility.

Below you can find the list of cases where yalp/jsonpath and PaesslerAG/jsonpath work differently.

Test JSON:

{
    "A":["string",23.3,3,true,false,null],
    "B":"value",
    "C":3.14,
    "D":{
        "C":3.1415,
        "V":["string2",{"C":3.141592}]
    }
}

special -1 index

expression:
$.A[:-1]

yalp/jsonpath:
["string", 23.3, 3.0, true, false]

PaesslerAG/jsonpath:
[]

unquoted key

expression:
$[A][0]

yalp/jsonpath:
"string"

PaesslerAG/jsonpath:
null

unquoted key

expression:
$[C,B]

yalp/jsonpath:
[3.14, "value"]

PaesslerAG/jsonpath:
[]

recursive search

expression:
$..C

yalp/jsonpath:
[3.1415, 3.141592]

PaesslerAG/jsonpath:
[3.14, 3.1415, 3.141592]

recursive search

expression:
$..["C"]

yalp/jsonpath:
[3.1415, 3.141592]

PaesslerAG/jsonpath:
[3.14, 3.1415, 3.141592]

You can check these cases using this online tester: https://codebeautify.org/jsonpath-tester.

So what we have so far:

• PaesslerAG/jsonpath doesn't handle special -1 index
• PaesslerAG/jsonpath doesn't handle unquoted keys
• yalp/jsonpath has a bug with recursive search

I'm not sure if the first two features are standard, but if we reject them we will break the compatibility.

So we have several options:

• stay on yalp/jsonpath (it seems that it has the LICENSE file now)
• fix PaesslerAG/jsonpath before switching to it
• add a possibility to switch the JSONPath engine (but this is an overkill I think)

[gavv]

yalp/jsonpath#6
yalp/jsonpath#7
yalp/jsonpath#8

[gavv]

All bugs I've found in yalp/jsonpath are now fixed in upstream. Since it also has a LICENSE file, I guess there is no urgency now to make a switch.

On the other hand, all important JSONPath features are now covered with httpexpect tests, so making a switch would be safe.

Switching to PaesslerAG/jsonpath makes sense since it seems to be a more complete implementation. However, compatibility issues should be addressed first. If someone is interested, pull requests are welcome.

[gavv]

Closing this for now.