XCTest vs SpecFlow comparison of testing frameworks
What are the differences between XCTest and SpecFlow?

XCTest

https://developer.apple.com/documentation/xctest

SpecFlow

https://specflow.org/
Programming language

Swift

.NET

Category

Unit Testing, Performance Testing

Acceptance Testing

General info

XCTest is the default testing framework for unit tests, performance tests, and some level of UI tests for iOS apps.

XCTest framework is a testing framework that enables developers write basic unit tests, performance tests, and some level of UI tests for iOS apps.

SpecFlow is a test automation solution for .NET

SpecFlow is a test automation solution for .NET which follows the BDD paradigm, and is part of the Cucumber family. SpecFlow tests are written with Gherkin, using the official Gherkin parser which allows you to write test cases using natural languages and supports over 70 languages.
xUnit
Set of frameworks originating from SUnit (Smalltalk's testing framework). They share similar structure and functionality.

Yes

Yes, it is an xUnit style framework

No

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

Yes

Developers can test individual front-end components with XCTest

Yes

Front-end behaviour is tested. With specflow specifications of the expected behaviours are made and specflow tests against this
Server-side
Allows testing the bahovior of a server-side code

Yes

Yes, developers can test individual back-end components with XCTest

Yes

Back-end behaviour is tested. Specifications of the expected behaviours are made and specflow tests against them
Fixtures
Allows defining a fixed, specific states of data (fixtures) that are test-local. This ensures specific environment for a single test

Yes

XCTest contains setup() and teardown() fixture methods for setting up and destroying test environments

Yes

BeforeTestRun and AfterTestRun are executed once for each thread which is a limitation of the current architecture.
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

Group fixtures are available in XCTest

N/A

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

SpecFlow contains a generator component. The SpecFlow IDE integration tries to locate the generator component in your project structure, in order to use the generator version matching the SpecFlow runtime in your project
Licence
Licence type governing the use and redistribution of the software

Apache License 2.0

BSD 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

You can create protocol mocks and class mocks with libraries such as MockFive or Cuckoo

Yes

Specflow intergrates well with mock to give it excellent mocking capabilities
Grouping
Allows organizing tests in groups

Yes

Developers can define test suites from the XCTestSuite class

Yes

You can create test suites with specflow
Other
Other useful information about the testing framework