Re-adding tests and restoring behavior where if a property is not fou…

…nd in the ancestor the custom and product must equal or it will be a conflict

oak-run/src/main/java/org/apache/jackrabbit/oak/index/merge/IndexDefMergerUtils.java

@@ -148,8 +148,6 @@ private static String mergeProperty(String path, String property, JsonObject anc
             return cp;
         } else if (Objects.equals(ap, cp)) {
             return pp;
-        } else if (ap == null) {
-            return cp; // if property doesn't exist in the ancestor, prefer customization over the product value
         } else {
             conflicts.add("Could not merge value; path=" + path + " property=" + property + "; ancestor=" + ap + "; custom=" + cp
                     + "; product=" + pp);

oak-run/src/test/java/org/apache/jackrabbit/oak/index/merge/IndexDefMergerScenariosTest.java

@@ -26,7 +26,6 @@
 import java.nio.charset.StandardCharsets;
 import java.util.Arrays;
 import java.util.Collection;
-import java.util.Optional;
 
 import org.apache.commons.io.IOUtils;
 import org.apache.jackrabbit.oak.commons.json.JsonObject;
@@ -41,9 +40,9 @@
  * Test merging index definitions.
  */
 @RunWith(Parameterized.class)
-public class IndexDefMergerScenariosTest {
+public class IndexDefMergerScenariosTest extends ParameterizedMergingTestBase {
 
-    private static final Logger log = LoggerFactory.getLogger(IndexDefMergerScenariosTest.class);
+    private static final Logger log = LoggerFactory.getLogger(IndexDefMergerConflictsTest.class);
 
     @Parameters(name = "{0}")
     public static Collection<Object[]> data() {
@@ -60,53 +59,17 @@ public static Collection<Object[]> data() {
         });
     }
 
-    public static Object[] testCase(String name, String testCaseFile) {
-        return new Object[] {
-                name,
-                testCaseFile
-        };
-    }
-
-    private final String testCaseFile;
-    private final String testCaseName;
-    private final JsonObject buildIndexes;
-    private final JsonObject runIndexes;
     private final JsonObject expectedIndexes;
 
     public IndexDefMergerScenariosTest(String name, String testCaseFile)
             throws IOException {
-        this.testCaseName = name;
-        this.testCaseFile = testCaseFile;
-        JsonObject testCase = readTestCaseFile(testCaseFile);
-        this.buildIndexes = getChild(testCase, "build");
-        this.runIndexes = getChild(testCase, "run");
-        this.expectedIndexes = getChild(testCase, "expected");
-    }
-
-    private JsonObject readTestCaseFile(String testCaseFileName) {
-        return Optional.ofNullable(IndexDefMergerScenariosTest.class.getResourceAsStream(testCaseFileName))
-                .map(in -> {
-                    try {
-                        return IOUtils.toString(in, StandardCharsets.UTF_8.toString());
-                    } catch (IOException e) {
-                        throw new IllegalArgumentException(
-                                "Unexpected IOException reading test case file: " + testCaseFileName, e);
-                    }
-                })
-                .map(s -> JsonObject.fromJson(s, true))
-                .orElseThrow(() -> new IllegalArgumentException("Unable to read test case file: " + testCaseFileName));
-    }
-
-    private JsonObject getChild(JsonObject testCase, String fieldName) {
-        return Optional.ofNullable(testCase.getChildren().get(fieldName))
-                .orElseThrow(() -> new IllegalArgumentException(
-                        "Unable to run test: " + testCaseName + ", Expected field " + fieldName + " not set"));
+        super(name, testCaseFile);
+        this.expectedIndexes = super.getTestCaseChild("expected");
     }
 
     @Test
-    public void testMerge() {
+    public void verifyExpectedMergeResult() {
         IndexDefMergerUtils.merge(buildIndexes, runIndexes);
-
         File output = new File("target" + File.separator + "surefire-output" + File.separator
                 + getClass().getCanonicalName().replace(".", "-") + File.separator + testCaseFile);
         try {

oak-run/src/test/resources/org/apache/jackrabbit/oak/index/merge/basic.json

@@ -1,7 +1,7 @@
 {
   "run": {
     "/oak:index/lucene": { "a": 1, "b": 10, "x": 1, "z": 2 },
-    "/oak:index/lucene-custom-1": { "a": 2, "b": 10, "c": 1, "x": 1 }
+    "/oak:index/lucene-custom-1": { "a": 2, "b": 10, "c": 1,  "x": 1 }
   },
   "build": {
     "/oak:index/lucene-2": { "a": 1, "b": 11, "d": 100, "z": 2 }

oak-run/src/test/resources/org/apache/jackrabbit/oak/index/merge/merge.txt

@@ -13,6 +13,12 @@
   "product": {"o": {"a": 1, "p": 20}},
   "expected": {"merges": ["/oak:index/test-2", "/oak:index/test-1-custom-1"], "o": {"a": 2, "c": 10, "p": 20 }}
 },
+{
+  "ancestor": {"o": {"a": 1}},
+  "custom": {},
+  "product": {"o": {"a": 2}},
+  "expected": {"merges": ["/oak:index/test-2", "/oak:index/test-1-custom-1"],"o": {"a": 2}}
+},
 {
   "ancestor": {"a": 1},
   "custom": {"a": 2},