Improvement: Add a possibility to do good JSON assertions

[wurzelkuchen]

Quick Description

In several projects we check for JSON data (REST, Google Analytics, etc.) These checks often result in a big unreadable text blob as an error message.
We can do better. We should add a helper class to assert JSON Strings. If an assertion fails however we need a good message and overview on the JSON data inside our allure report.

User Story

As a test report reader,
I want to see directly what is wrong with the JSON data, compared to the expected test data
so that I don't waste time fiddling around with the data.

Upfront research

• Check if there's a well maintained and useful json compare library for Java
• Search for a good client side JSON diff library in JS
• The JSON Diff Library should be hosted in a CDN

Functional Requirements

• Add a helper class for JSON assertion
• Add Methods for:
• JSONAssert.assertEquals(actualData,expectedData)
• JSONAssert.assertHas(actualData,jsonPath)
• JSONAssert.assertEquals(data,jsonPath)
• JSONAssert.assertMatch(data,jsonPath,regExp) (Updated 2024-08-21)
• think about what additional assertion methods could be useful
• Give every assertion method the possibility to add a custom message
• For the (non custom) error messages, keep in mind that they should work with and without allure
• If the assertion fails, add a nice json diff view to the allure report before throwing an AssertionError.
• For the diff view we should do a two column view marking the differences with colors.
• Add support for different Comparison modes (Strict, StrictOrder, Lenient, nonExtensible) (Updated 2024-08-21)

Note: for the methods with jsonPath be reminded that those can have simple fields as well as complex json data as a result.

Documentation Requirements

• Add a documentation page
• Mention the allure diff view on the reports page of the wiki

Test Requirements

• Write sufficient unit tests
• Do a smoke test using the feature with an external library like the neodymium example (check if the allure view works)

[wurzelkuchen]

Update: after internal discussion the requirements were adapted. We want to support different JSON compare modes, as we need those in different customer projects