From 9baeeb987d13d85e81023cbaa726c8af38b19f64 Mon Sep 17 00:00:00 2001
From: Sam Rawlins <sam.rawlins@gmail.com>
Date: Wed, 18 Jul 2018 13:58:09 -0700
Subject: [PATCH] Throw an error when stubbing a non-mock method (#159)

---
 lib/src/mock.dart      | 4 ++++
 test/mockito_test.dart | 9 +++++++++
 2 files changed, 13 insertions(+)

diff --git a/lib/src/mock.dart b/lib/src/mock.dart
index 8a398e6e..76010722 100644
--- a/lib/src/mock.dart
+++ b/lib/src/mock.dart
@@ -348,6 +348,10 @@ class PostExpectation<T> {
   }
 
   void _completeWhen(Answering<T> answer) {
+    if (_whenCall == null) {
+      throw new StateError(
+          'Mock method was not called within `when()`. Was a real method called?');
+    }
     _whenCall._setExpected<T>(answer);
     _whenCall = null;
     _whenInProgress = false;
diff --git a/test/mockito_test.dart b/test/mockito_test.dart
index 3223cb0d..fc2b62d7 100644
--- a/test/mockito_test.dart
+++ b/test/mockito_test.dart
@@ -45,6 +45,8 @@ abstract class _AbstractFoo implements _Foo {
   String bar() => baz();
 
   String baz();
+
+  String quux() => "Real";
 }
 
 class _MockFoo extends _AbstractFoo with Mock {}
@@ -288,6 +290,13 @@ void main() {
             .thenReturn("99");
       }, throwsArgumentError);
     });
+
+    test("should throw if attempting to stub a real method", () {
+      var foo = new _MockFoo();
+      expect(() {
+        when(foo.quux()).thenReturn("Stub");
+      }, throwsStateError);
+    });
   });
 
   group("throwOnMissingStub", () {