From d9bdfe680ad2e61b3d8d9a697531b5e05793b782 Mon Sep 17 00:00:00 2001
From: Matthew Ouyang <mouyang@exchangesolutions.com>
Date: Mon, 31 Dec 2018 17:42:21 -0500
Subject: [PATCH] Fixes #1578: append mocks to existing MockitoSession

- Problem - JUnitRule detects an unfinished mocking session when the apply method is invoked more than once.  This commonly happens with Runners that enable developers to write nested test classes.
- Fix - If a MockitoSession has been established for JUnitRule, then use that and initialize any new mocks (typically from a nested test class).
- Test - Instantiate one @Rule and assign it to a second one.  This will simulate the apply method being invoked more than once without introducing a new test dependency.
---
 .../org/mockito/internal/junit/JUnitRule.java   | 17 +++++++++++------
 .../junitrule/MockitoJUnitRuleTest.java         |  4 ++++
 2 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/src/main/java/org/mockito/internal/junit/JUnitRule.java b/src/main/java/org/mockito/internal/junit/JUnitRule.java
index ba00c343ae..3bd3dacfe0 100644
--- a/src/main/java/org/mockito/internal/junit/JUnitRule.java
+++ b/src/main/java/org/mockito/internal/junit/JUnitRule.java
@@ -7,6 +7,7 @@
 import org.junit.runners.model.FrameworkMethod;
 import org.junit.runners.model.Statement;
 import org.mockito.Mockito;
+import org.mockito.MockitoAnnotations;
 import org.mockito.MockitoSession;
 import org.mockito.internal.session.MockitoSessionLoggerAdapter;
 import org.mockito.plugins.MockitoLogger;
@@ -34,12 +35,16 @@ public JUnitRule(MockitoLogger logger, Strictness strictness) {
 	public Statement apply(final Statement base, final FrameworkMethod method, final Object target) {
         return new Statement() {
             public void evaluate() throws Throwable {
-                session = Mockito.mockitoSession()
-                    .name(target.getClass().getSimpleName() + "." + method.getName())
-                    .strictness(strictness)
-                    .logger(new MockitoSessionLoggerAdapter(logger))
-                    .initMocks(target)
-                    .startMocking();
+                if (session == null) {
+                    session = Mockito.mockitoSession()
+                                     .name(target.getClass().getSimpleName() + "." + method.getName())
+                                     .strictness(strictness)
+                                     .logger(new MockitoSessionLoggerAdapter(logger))
+                                     .initMocks(target)
+                                     .startMocking();
+                } else {
+                    MockitoAnnotations.initMocks(target);
+                }
                 Throwable testFailure = evaluateSafely(base);
                 session.finishMocking(testFailure);
                 if (testFailure != null) {
diff --git a/src/test/java/org/mockitousage/junitrule/MockitoJUnitRuleTest.java b/src/test/java/org/mockitousage/junitrule/MockitoJUnitRuleTest.java
index dfec883488..3ea7adde3e 100644
--- a/src/test/java/org/mockitousage/junitrule/MockitoJUnitRuleTest.java
+++ b/src/test/java/org/mockitousage/junitrule/MockitoJUnitRuleTest.java
@@ -19,6 +19,10 @@ public class MockitoJUnitRuleTest {
     @Rule
     public MockitoRule mockitoRule = MockitoJUnit.rule();
 
+    // Fixes #1578: Protect against multiple execution.
+    @Rule
+    public MockitoRule mockitoRule2 = mockitoRule;
+
     @Mock
     private Injected injected;