From 3c8112c0d474b4373e738dee63f271a6884b6021 Mon Sep 17 00:00:00 2001
From: David van Geest <dvangeest@pagerduty.com>
Date: Wed, 15 Jun 2016 15:11:18 -0400
Subject: [PATCH] Better error message/exception when mocks are called after
 verifyExpectations.

---
 .../scala/org/scalamock/function/FakeFunction.scala | 13 +++++++++----
 .../org/scalamock/test/scalatest/PathSpecTest.scala | 10 ++++++++++
 2 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/core/src/main/scala/org/scalamock/function/FakeFunction.scala b/core/src/main/scala/org/scalamock/function/FakeFunction.scala
index ca720c24..a0c19c90 100644
--- a/core/src/main/scala/org/scalamock/function/FakeFunction.scala
+++ b/core/src/main/scala/org/scalamock/function/FakeFunction.scala
@@ -37,9 +37,14 @@ abstract class FakeFunction(protected val mockContext: MockContext, private[scal
   private def expectationContext = mockContext.expectationContext
 
   def handle(arguments: Product): Any = {
-    val call = new Call(this, arguments)
-    callLog += call
-    expectationContext.handle(call) getOrElse onUnexpected(call)
+    if (callLog != null) {
+      val call = new Call(this, arguments)
+      callLog += call
+      expectationContext.handle(call) getOrElse onUnexpected(call)
+    } else {
+      val msg = "Can't log call to mock object, have expectations been verified already?"
+      throw new RuntimeException(msg)
+    }
   }
   
   protected def onUnexpected(call: Call): Any
@@ -179,4 +184,4 @@ abstract class FakeFunction22[T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12,
   extends FakeFunction(mockContext, name) with Function22[T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22, R] with NiceToString {
 
   def apply(v1: T1, v2: T2, v3: T3, v4: T4, v5: T5, v6: T6, v7: T7, v8: T8, v9: T9, v10: T10, v11: T11, v12: T12, v13: T13, v14: T14, v15: T15, v16: T16, v17: T17, v18: T18, v19: T19, v20: T20, v21: T21, v22: T22) = handle((v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22)).asInstanceOf[R]
-}
\ No newline at end of file
+}
diff --git a/frameworks/scalatest/src/test/scala/org/scalamock/test/scalatest/PathSpecTest.scala b/frameworks/scalatest/src/test/scala/org/scalamock/test/scalatest/PathSpecTest.scala
index 3cbd2917..792fd515 100644
--- a/frameworks/scalatest/src/test/scala/org/scalamock/test/scalatest/PathSpecTest.scala
+++ b/frameworks/scalatest/src/test/scala/org/scalamock/test/scalatest/PathSpecTest.scala
@@ -60,4 +60,14 @@ class PathSpecTest extends path.FunSpec with Matchers with PathMockFactory {
     testFailedException.getMessage() should include("mockFun(bottom-level) once (never called - UNSATISFIED)")
   }
 
+  describe("PathSpec") {
+    val mockFun = mockFunction[String, Unit]
+
+    it("throws an exception with good error message if the mock is called after expectations are verified") {
+      verifyExpectations()
+      val thrown = the [RuntimeException] thrownBy(mockFun("called after verification"))
+      thrown should not be a[NullPointerException]
+      thrown.getMessage should include ("have expectations been verified already?")
+    }
+  }
 }