Improve API (append expected state change)

Author: luizmb

README.md

@@ -33,9 +33,9 @@ assert(
             scheduler.advance(by: .seconds(5))
         }
 
-        Send(action: .anotherAction(.stopSomething)) { expectedStateChange in
+        Send(action: .anotherAction(.stopSomething)).expectStateToHaveChanged { state in
             // if during Send or Receive action, your state is expected to mutate, you must indicate which change is expected to happen here:
-            expectedStateChange.somePropertyShouldHaveChangedTo = true
+            state.somePropertyShouldHaveChangedTo = true
             // any unexpected state mutation will fail the test, as well as any expected state mutation that doesn't occur, will also fail the test
         }
 
@@ -52,9 +52,9 @@ assert(
             } else {
                 return false
             }
-        } stateChange: { expectedStateChange in
+        }.expectStateToHaveChanged { state in
             // if during Send or Receive action, your state is expected to mutate, you must indicate which change is expected to happen here:
-            expectedStateChange.somePropertyShouldHaveChangedTo = true
+            state.somePropertyShouldHaveChangedTo = true
             // any unexpected state mutation will fail the test, as well as any expected state mutation that doesn't occur, will also fail the test
         }
     }

Sources/TestingExtensions/UseCaseTests.swift

@@ -71,6 +71,13 @@ public struct Send<ActionType, StateType>: StepProtocol {
     public var asStep: Step<ActionType, StateType> {
         .send(action: action(), file: file, line: line, stateChange: stateChange)
     }
+
+    public func expectStateToHaveChanged(_ expectedMutation: @escaping (inout StateType) -> Void = { _ in }) -> Send {
+        .init(action: action(), file: file, line: line, stateChange: { state in
+            self.stateChange(&state)
+            expectedMutation(&state)
+        })
+    }
 }
 
 public struct Receive<ActionType, StateType>: StepProtocol {
@@ -105,6 +112,13 @@ public struct Receive<ActionType, StateType>: StepProtocol {
     public var asStep: Step<ActionType, StateType> {
         .receive(isExpectedAction: isExpectedAction, file: file, line: line, stateChange: stateChange)
     }
+
+    public func expectStateToHaveChanged(_ expectedMutation: @escaping (inout StateType) -> Void = { _ in }) -> Receive {
+        .init(isExpectedAction: isExpectedAction, file: file, line: line, stateChange: { state in
+            self.stateChange(&state)
+            expectedMutation(&state)
+        })
+    }
 }
 
 public struct SideEffectResult<ActionType, StateType>: StepProtocol {