Only run injection once

Add regression test that makers sure constructor injection is used when possible
Fixes #2602

src/main/java/org/mockito/internal/configuration/InjectingAnnotationEngine.java

@@ -45,25 +45,14 @@ public class InjectingAnnotationEngine implements AnnotationEngine {
     public AutoCloseable process(Class<?> clazz, Object testInstance) {
         List<AutoCloseable> closeables = new ArrayList<>();
         closeables.addAll(processIndependentAnnotations(testInstance.getClass(), testInstance));
-        closeables.addAll(processInjectMocks(testInstance.getClass(), testInstance));
+        closeables.add(injectCloseableMocks(testInstance));
         return () -> {
             for (AutoCloseable closeable : closeables) {
                 closeable.close();
             }
         };
     }
 
-    private List<AutoCloseable> processInjectMocks(
-            final Class<?> clazz, final Object testInstance) {
-        List<AutoCloseable> closeables = new ArrayList<>();
-        Class<?> classContext = clazz;
-        while (classContext != Object.class) {
-            closeables.add(injectCloseableMocks(testInstance));
-            classContext = classContext.getSuperclass();
-        }
-        return closeables;
-    }
-
     private List<AutoCloseable> processIndependentAnnotations(
             final Class<?> clazz, final Object testInstance) {
         List<AutoCloseable> closeables = new ArrayList<>();

subprojects/junit-jupiter/src/test/java/org/mockitousage/InjectMocksTest.java

@@ -0,0 +1,98 @@
+/*
+ * Copyright (c) 2018 Mockito contributors
+ * This program is made available under the terms of the MIT License.
+ */
+package org.mockitousage;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.InjectMocks;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class ToBeMockedInTestSuperClass{
+    int identifier;
+
+    public ToBeMockedInTestSuperClass(int identifier) {
+        this.identifier = identifier;
+    }
+}
+
+class ToBeMocked{
+    int identifier;
+
+    public ToBeMocked(int identifier) {
+        this.identifier = identifier;
+    }
+}
+
+class TestClassToBeInitiatedViaConstructorInSuperClass {
+    ToBeMockedInTestSuperClass toBeMockedInTestSuperClass;
+
+    public TestClassToBeInitiatedViaConstructorInSuperClass(ToBeMockedInTestSuperClass toBeMockedInTestSuperClass) {
+        assert toBeMockedInTestSuperClass != null;
+        this.toBeMockedInTestSuperClass = new ToBeMockedInTestSuperClass(42);
+    }
+}
+
+class TestClassToBeInitiatedViaConstructor{
+    ToBeMockedInTestSuperClass toBeMockedInTestSuperClass;
+    ToBeMocked toBeMocked;
+
+    public TestClassToBeInitiatedViaConstructor(ToBeMocked toBeMocked, ToBeMockedInTestSuperClass toBeMockedInTestSuperClass) {
+        assert toBeMocked != null;
+        assert toBeMockedInTestSuperClass != null;
+        this.toBeMocked = new ToBeMocked(42);
+        this.toBeMockedInTestSuperClass = new ToBeMockedInTestSuperClass(42);
+    }
+}
+
+class SuperTestClass {
+    @Mock
+    ToBeMockedInTestSuperClass toBeMockedInTestSuperClass;
+
+    @InjectMocks
+    TestClassToBeInitiatedViaConstructorInSuperClass testClassToBeInitiatedViaConstructorInSuperClass;
+
+}
+
+@ExtendWith(MockitoExtension.class)
+class InjectMocksTest extends SuperTestClass {
+
+    @Mock
+    ToBeMocked toBeMocked;
+
+    @InjectMocks
+    TestClassToBeInitiatedViaConstructor testClassToBeInitiatedViaConstructor;
+
+    /**
+     * Checks that {@link #testClassToBeInitiatedViaConstructor} holds instances that have identifier 42.
+     * It being 42 is proof that constructor injection was used over field injection.
+     */
+    @Test
+    void given_instanceToBeInitializedByMockito_when_mocksRequestedByConstructorAreInTestAndSuperClass_should_useConstructorInjection() {
+        assertThat(testClassToBeInitiatedViaConstructor)
+            .extracting(
+                testInstance-> testInstance.toBeMocked.identifier,
+                testInstance-> testInstance.toBeMockedInTestSuperClass.identifier
+            )
+            .containsExactly(
+                42,
+                42
+            );
+    }
+
+    /**
+     * Checks that {@link #testClassToBeInitiatedViaConstructorInSuperClass} holds instances that have identifier 42.
+     * It being 42 is proof that constructor injection was used over field injection.
+     */
+    @Test
+    public void given_instanceInSuperClassToBeInitializedByMockito_when_mocksRequestedAreInSuperClass_should_useConstructorInjection(){
+        assertThat(testClassToBeInitiatedViaConstructorInSuperClass)
+            .extracting(yetAnotherClas1 -> yetAnotherClas1.toBeMockedInTestSuperClass.identifier)
+            .isEqualTo(42);
+    }
+
+}