Concordion vs Robot Framework comparison of testing frameworks
What are the differences between Concordion and Robot Framework?

Concordion

https://concordion.org/

Robot Framework

https://robotframework.org/
Programming language

Java

Python

Category

Acceptance Testing

General info

Concordion is a tool used to write and manage automated acceptance tests in Java based projects

Concordion specifications are written in Markdown, HTML or Excel and then instrumented with special links, attributes or comments respectively. When the corresponding test fixture class is run, Concordion interprets the instrumentation to execute the test. Concordion lets you write them in normal language using paragraphs, tables and proper punctuation. This makes specification more natural to read and write, and helps everyone to understand and agree about what a feature is supposed to do.

Robot is a Python framework used for acceptance/functional testing

Robot is an automated test framework which has a simple plain text syntax and can be extended easily with Python or Java libraries. It can run on the .net-based IronPython and on Jython which is Java based.
xUnit
Set of frameworks originating from SUnit (Smalltalk's testing framework). They share similar structure and functionality.

No

No

Client-side
Allows testing code execution on the client, such as a web browser

Yes

You can specify tests for front-end components and functionality with concordion

Yes

Robot has a rich library and can also be easily integrated with Selenium for browser automation to test front-end components
Server-side
Allows testing the bahovior of a server-side code

Yes

You can test server-side components and functionality with concordion.

Yes

Robot can be used for back-end tests as well
Fixtures
Allows defining a fixed, specific states of data (fixtures) that are test-local. This ensures specific environment for a single test

Yes

Concordion contains fixtures which correspond to a specific instrumentation within the code. That is when specifications are written they are instrumented with special links, attributes or comments which are then run with their corresponding fixtures

There is no inbuilt way to work with fixtures in Robot however it can integrate with unittest and use fixtures that way
Group fixtures
Allows defining a fixed, specific states of data for a group of tests (group-fixtures). This ensures specific environment for a given group of tests.

Yes

One can group fixtures in concordion

By integrating with unittest
Generators
Supports data generators for tests. Data generators generate input data for test. The test is then run for each input data produced in this way.

N/A

Yes

Robot has a library called the Robot Framework Faker library. It contains 147 keywords used for generating random test data
Licence
Licence type governing the use and redistribution of the software

Apache License 2.0

Apache License 2.0

Mocks
Mocks are objects that simulate the behavior of real objects. Using mocks allows testing some part of the code in isolation (with other parts mocked when needed)

Yes

By use of third party libraries like mockito

Yes

Robot can access Python's mock library for mocking
Grouping
Allows organizing tests in groups

Yes

One can group tests into suites

Yes

One can create a test suite with Robot
Other
Other useful information about the testing framework