Macros for Strobl Mocks

A collection of Swift Macros for reducing the assertions required to test the injected dependencies in any given unit test fully.

Use the @StroblMock macro to mark Strobl mocks present in a test class:

    @StroblMock var cookieStore: MockCookieStoring!
    @StroblMock var urlSession: MockDataTaskCreating!
    @StroblMock var dateFactory: MockDateCreating!
    @StroblMock var jsonDecoder: MockJSONDecoding!
    @StroblMock var jsonEncoder: MockJSONEncoding!
    @StroblMock var jsonSerializer: MockJSONSerializing!
    @StroblMock var semaphore: MockSemaphore!

Use the @UsesStroblMocks macro to generate helper code.

@UsesStroblMocks
final class Test05OptionSetValueTests: XCTestCase {

...

}

The @UsesStroblMocks macro will define two elements.

1. A enum that lists the @StroblMocks in the test class:

   enum StroblMock {
   	case mock1
   	case mock2
   }

   The enum is used by the second generated element. (You can use it if you want/need to.)

2. A helper custom XCT Assertion to eliminate the need to write XCTAssertEquals(mock.calledMethods, []) assertions

   func verifyStroblMocksUnused(
   	except excludedMocks: Set<StroblMock> = [], 
   	file: StaticString = #filePath, 
   	line: UInt = #line
   	)

How to use verifyStroblMocksUnused(except:file:line:)

If you have a test that will not cause any interaction with the Strobl mocks, you can write the test like this:

func testSomething() {
     // Setup

     // Call thing being tested

     verifyStroblMocksUnused()
     XCTAssert ... whatever needs to be tested
}

When this test is run, it will test whatever is being tested and, by calling verifyStroblMocksUnused(), verifies that the Strobl mocks weren't used too.

---

When you have a test that will use one or more of the Strobl mocks, you can write the test like this:

func testSomethingThatUsesMock1ButNotMock2() {
    // Setup
    // Call thing being tested
    verifyStroblMocksUnused(except: .mock1)
    XCTAssertEqual(mock1.calledMethods, [.someMethod])
    XCTAssertEqual(mock1.assignedParameters, [])
    XCTAssert ... whatever else needs to be tested
}

When this test is run, the call to verifyStroblMocksUnused() will test that all the Strobl mocks except mock1 were not used. Then, the subsequent assertions verify the expected functionality of mock1 was used.