Add more tests

server/src/test/java/org/elasticsearch/index/mapper/MapperBuilderContextTest.java

@@ -0,0 +1,30 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0 and the Server Side Public License, v 1; you may not use this file except
+ * in compliance with, at your election, the Elastic License 2.0 or the Server
+ * Side Public License, v 1.
+ */
+
+package org.elasticsearch.index.mapper;
+
+import org.elasticsearch.test.ESTestCase;
+
+public class MapperBuilderContextTest extends ESTestCase {
+
+    public void testRoot() {
+        MapperBuilderContext root = MapperBuilderContext.root(false, false);
+        assertFalse(root.isSourceSynthetic());
+        assertFalse(root.isDataStream());
+        assertEquals(MapperService.MergeReason.MAPPING_UPDATE, root.getMergeReason());
+    }
+
+    public void testRootWithMergeReason() {
+        MapperService.MergeReason mergeReason = randomFrom(MapperService.MergeReason.values());
+        MapperBuilderContext root = MapperBuilderContext.root(false, false, mergeReason);
+        assertFalse(root.isSourceSynthetic());
+        assertFalse(root.isDataStream());
+        assertEquals(mergeReason, root.getMergeReason());
+    }
+
+}

server/src/test/java/org/elasticsearch/index/mapper/MapperMergeContextTests.java

@@ -29,4 +29,10 @@ public void testAddFieldIfPossibleUnlimited() {
         assertTrue(context.decrementFieldBudgetIfPossible(Integer.MAX_VALUE));
     }
 
+    public void testMergeReasons() {
+        MapperService.MergeReason mergeReason = randomFrom(MapperService.MergeReason.values());
+        MapperMergeContext context = MapperMergeContext.root(false, false, mergeReason, Integer.MAX_VALUE);
+        assertEquals(mergeReason, context.getMapperBuilderContext().getMergeReason());
+    }
+
 }