Concordion vs go test/testing comparison of testing frameworks
What are the differences between Concordion and go test/testing?

Concordion

https://concordion.org/

go test/testing

https://golang.org/pkg/testing/
Programming language

Java

Go

Category

Unit 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.

go test is an inbuilt tool/command for conducting automated tests in Golang while testing is the inbuilt testing library

Testing is the package that is shipped with go and combines with the go test command to provide a minimal but complete testing experience
xUnit
Set of frameworks originating from SUnit (Smalltalk's testing framework). They share similar structure and functionality.

No

No

However there are Plugins such as https://github.com/tebeka/go2xunitto convert the output of Go testing library into xUnit format
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

Yes it can be used effectively for front-end testing
Server-side
Allows testing the bahovior of a server-side code

Yes

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

Yes

Yes, it is used by developers for end-to-end testing so the back-end can be tested easily 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

Yes

Yes it's straightforward in that first when you run 'go test' for packages in the scope the test will be executed with its working directory set to the source directory of the package being tested. Second the 'go test' tool will ignore any directory in your $GOPATH that starts with the word 'testdata' , starts with a period or an underscore
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

Yes

Group fixtures can be done following a similar procedure as a single fixture
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

They are available by importing a package called 'gotests' (https://github.com/cweill/gotests)
Licence
Licence type governing the use and redistribution of the software

Apache License 2.0

MIT License

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

By use of a third party library GoMock which intergrates well with the testing library
Grouping
Allows organizing tests in groups

Yes

One can group tests into suites

Yes

The short answer is yes, by use of table tests which are a great way of performing multiple I/O tests on a function or behaviour with minimal code
Other
Other useful information about the testing framework