Testing on syntax tree obtained from real code using JavaParser

src/main/java/org/cqfn/astranaut/core/algorithms/DiffTreeBuilder.java

@@ -76,7 +76,7 @@ public DiffTreeBuilder(final Tree before) {
 
     /**
      * Builds a difference tree based on the original tree and the tree after changes.
-     * @param after Root node of tree before the changes
+     * @param after Root node of tree after the changes
      * @param mapper A mapper used for node mappings
      * @return Result of operation, {@code true} if difference tree was built
      */
@@ -95,6 +95,16 @@ public boolean build(final Node after, final Mapper mapper) {
         return result;
     }
 
+    /**
+     * Builds a difference tree based on the original tree and the tree after changes.
+     * @param after Syntax tree after the changes
+     * @param mapper A mapper used for node mappings
+     * @return Result of operation, {@code true} if difference tree was built
+     */
+    public boolean build(final Tree after, final Mapper mapper) {
+        return this.build(after.getRoot(), mapper);
+    }
+
     /**
      * Adds an action to the difference tree that inserts a node after another node.
      * If no other node is specified, inserts at the beginning of the children's list.

src/main/java/org/cqfn/astranaut/core/base/DiffNode.java

@@ -148,8 +148,8 @@ public boolean insertNodeAfter(final Node node, final Node after) {
             final ListIterator<DiffTreeItem> iterator = this.children.listIterator();
             while (iterator.hasNext()) {
                 final Node child = iterator.next();
-                if (child instanceof DiffNode
-                    && ((DiffNode) child).getPrototype() == after) {
+                if (child instanceof DiffNode && ((DiffNode) child).getPrototype() == after
+                    || child instanceof Insert && ((Insert) child).getAfter() == after) {
                     iterator.add(new Insert(node));
                     result = true;
                     break;

src/test/java/org/cqfn/astranaut/core/algorithms/mapping/TopDownMapperTest.java

@@ -29,9 +29,15 @@
 import java.util.Map;
 import java.util.Set;
 import java.util.TreeMap;
+import org.cqfn.astranaut.core.algorithms.DiffTreeBuilder;
+import org.cqfn.astranaut.core.base.DefaultFactory;
+import org.cqfn.astranaut.core.base.DiffTree;
 import org.cqfn.astranaut.core.base.DraftNode;
 import org.cqfn.astranaut.core.base.Insertion;
 import org.cqfn.astranaut.core.base.Node;
+import org.cqfn.astranaut.core.base.Tree;
+import org.cqfn.astranaut.core.utils.FilesReader;
+import org.cqfn.astranaut.core.utils.JsonDeserializer;
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
 
@@ -41,6 +47,11 @@
  */
 @SuppressWarnings("PMD.TooManyMethods")
 class TopDownMapperTest {
+    /**
+     * The folder with test resources.
+     */
+    private static final String TESTS_PATH = "src/test/resources/heavy/";
+
     @Test
     void testIdenticalTrees() {
         final String description = "A(B(C, D))";
@@ -426,4 +437,46 @@ void thirdTestComplexChanges() {
         final Map<Node, Node> replaced = mapping.getReplaced();
         Assertions.assertEquals(1, replaced.size());
     }
+
+    @Test
+    void firstTestOnRealSyntaxTree() {
+        final Tree first = this.readSyntaxTreeFormFile("real_tree_from_java_parser_1.json");
+        final Tree second = this.readSyntaxTreeFormFile("real_tree_from_java_parser_2.json");
+        final Mapper mapper = TopDownMapper.INSTANCE;
+        final DiffTreeBuilder builder = new DiffTreeBuilder(first);
+        final boolean building = builder.build(second, mapper);
+        Assertions.assertTrue(building);
+        final DiffTree diff = builder.getDiffTree();
+        final Tree before = diff.getBefore();
+        Assertions.assertTrue(before.deepCompare(first));
+        final Tree after = diff.getAfter();
+        Assertions.assertTrue(after.deepCompare(second));
+    }
+
+    /**
+     * Returns content of the specified file.
+     * @param name The name of the file
+     * @return The file content
+     */
+    private String getFileContent(final String name) {
+        final String file = TopDownMapperTest.TESTS_PATH.concat(name);
+        final String source = new FilesReader(file).readAsStringNoExcept();
+        Assertions.assertFalse(source.isEmpty());
+        return source;
+    }
+
+    /**
+     * Reads syntax tree from a JSON file.
+     * @param name The name of the file
+     * @return Syntax tree
+     */
+    private Tree readSyntaxTreeFormFile(final String name) {
+        final JsonDeserializer deserializer = new JsonDeserializer(
+            this.getFileContent(name),
+            language -> DefaultFactory.EMPTY
+        );
+        final Tree tree = deserializer.convert();
+        Assertions.assertEquals("CompilationUnit", tree.getRoot().getTypeName());
+        return tree;
+    }
 }