Add trait that resets all mocks after each test

README.md

@@ -134,6 +134,26 @@ the mockito-scala API available in one go, i.e.
 class MyTest extends WordSpec with MockitoFixture
 ```
 
+## `org.mockito.integrations.scalatest.ResetMocksAfterEachTest`
+
+Inspired by [this](https://stackoverflow.com/questions/51387234/is-there-a-per-test-non-specific-mock-reset-pattern-using-scalaplayspecmockito) StackOverflow question,
+mockito-scala provides this trait that helps to automatically reset any existent mock after each test is run
+The trait has to be mixed **after** `org.mockito.MockitoSugar` in order to work, otherwise your test will not compile
+The code shown in the StackOverflow question would look like this if using this mechanism
+
+```scala
+TestClass extends PlaySpec with MockitoSugar with ResetMocksAfterEachTest
+
+private val foo = mock[Foo]
+
+override def fakeApplication(): Application = new GuiceApplicationBuilder().overrides(bind[Foo].toInstance(foo)).build
+```
+
+The main advantage being we don't have to remember to reset each one of the mocks...
+
+If for some reason we want to have a mock that is not reset automatically while using this trait, then it should be 
+created via the companion object of `org.mockito.MockitoSugar` so is not tracked by this mechanism
+
 ## Experimental features
 
 * **by-name** arguments is currently an experimental feature as the implementation is a bit hacky and it gave some people problems

core/src/main/scala/org/mockito/integrations/scalatest/ResetMocksAfterEachTest.scala

@@ -0,0 +1,38 @@
+package org.mockito.integrations.scalatest
+
+import java.util.concurrent.ConcurrentHashMap
+
+import org.mockito.stubbing.Answer
+import org.mockito.{ MockCreator, MockSettings, MockitoSugar }
+import org.scalatest.{ Outcome, TestSuite }
+
+import scala.reflect.ClassTag
+import scala.reflect.runtime.universe.TypeTag
+
+trait ResetMocksAfterEachTest extends TestSuite with MockCreator { self: MockCreator =>
+
+  private val mocksToReset = ConcurrentHashMap.newKeySet[AnyRef]()
+
+  private def resetAll(): Unit = mocksToReset.forEach(MockitoSugar.reset(_))
+
+  override protected def withFixture(test: NoArgTest): Outcome = {
+    val outcome = super.withFixture(test)
+    resetAll()
+    outcome
+  }
+
+  private def addMock[T <: AnyRef](mock: T) = {
+    mocksToReset.add(mock)
+    mock
+  }
+
+  abstract override def mock[T <: AnyRef: ClassTag: TypeTag]: T = addMock(super.mock[T])
+
+  abstract override def mock[T <: AnyRef: ClassTag: TypeTag](defaultAnswer: Answer[_]): T =
+    addMock(super.mock[T](defaultAnswer))
+
+  abstract override def mock[T <: AnyRef: ClassTag: TypeTag](mockSettings: MockSettings): T =
+    addMock(super.mock[T](mockSettings))
+
+  abstract override def mock[T <: AnyRef: ClassTag: TypeTag](name: String): T = addMock(super.mock[T](name))
+}

core/src/test/scala/org/mockito/integrations/scalatest/ResetMocksAfterEachTestTest.scala

@@ -0,0 +1,38 @@
+package org.mockito.integrations.scalatest
+
+import org.mockito.MockitoSugar
+import org.scalatest.{Matchers, WordSpec}
+
+class ResetMocksAfterEachTestTest extends WordSpec with MockitoSugar with ResetMocksAfterEachTest with Matchers {
+
+  trait Foo {
+    def bar(a: String) = "bar"
+  }
+
+  val foo = mock[Foo]
+
+  "ResetMocksAfterEachTest" should {
+
+    "have clean state for test 1" in {
+
+      verifyZeroInteractions(foo)
+
+      when(foo.bar("pepe")) thenReturn "mocked"
+
+      foo.bar("pepe") shouldBe "mocked"
+
+    }
+
+    "have clean state for test 2" in {
+
+      verifyZeroInteractions(foo)
+
+      when(foo.bar("pepe")) thenReturn "mocked2"
+
+      foo.bar("pepe") shouldBe "mocked2"
+
+    }
+
+  }
+
+}