refactoring, tests

src/main/java/com/jetbrains/jacobfs/tree/TreeLocator.java

@@ -17,7 +17,6 @@ public class TreeLocator {
 
     private TreeLocator() {
     }
-    //TODO test for too big locator
 
     public static TreeLocator init(Path path) throws IOException {
         TreeLocator treeLocator = new TreeLocator();

src/main/java/com/jetbrains/jacobfs/tree/TreeLocatorEncoder.java

@@ -11,16 +11,19 @@ public final class TreeLocatorEncoder {
     public static final String END_LINE_TAG = "\n";
 
     public void saveTreeLocatorToFile(RootNode rootNode, TreeLocatorMetadata treeLocatorMetadata) throws IOException {
-        String string = encode(rootNode);
+        String encoded = encode(rootNode);
+        if (encoded.length() > treeLocatorMetadata.getTreeLocatorReservedSpace()) {
+            throw new RuntimeException("TreeLocator is too big to be saved! Last command has not been persisted");
+        }
         try (RandomAccessFile randomAccessFile = new RandomAccessFile(treeLocatorMetadata.getFile(), "rw")) {
             randomAccessFile.seek(treeLocatorMetadata.getTreeLocatorOffset());
-            randomAccessFile.writeBytes(string);
+            randomAccessFile.writeBytes(encoded);
         }
-        treeLocatorMetadata.setTreeLocatorLength(string.length());
+        treeLocatorMetadata.setTreeLocatorLength(encoded.length());
         treeLocatorMetadata.saveState();
     }
 
-    public String encode(DirNode rootNode) {
+    public String encode(RootNode rootNode) {
         StringBuilder sb = new StringBuilder();
         appendToStringBuilder(rootNode, sb);
         return sb.toString();

src/test/java/com/jetbrains/jacobfs/tree/TreeLocatorEncoderTest.java

@@ -0,0 +1,53 @@
+package com.jetbrains.jacobfs.tree;
+
+import org.junit.jupiter.api.Test;
+
+import java.nio.file.FileAlreadyExistsException;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.mockito.Mockito.*;
+
+class TreeLocatorEncoderTest {
+
+    @Test
+    void shouldThrowIfTreeLocatorTooBig() {
+        TreeLocatorMetadata mockedTLM = mock(TreeLocatorMetadata.class);
+        int reservedSpace = 8;
+        when(mockedTLM.getTreeLocatorReservedSpace()).thenReturn(reservedSpace);
+
+        TreeLocatorEncoder treeLocatorEncoder = spy(new TreeLocatorEncoder());
+        doReturn(new String(new byte[reservedSpace + 1])).when(treeLocatorEncoder).encode(any());
+        assertThrows(RuntimeException.class,
+                () -> treeLocatorEncoder.saveTreeLocatorToFile(new RootNode(), mockedTLM));
+    }
+
+    @Test
+    void shouldEncodeDecode() throws FileAlreadyExistsException {
+        DirNode lvl31 = new DirNode("lvl3");
+        lvl31.addFileNode(new FileNode("31.txt", 0L, 8));
+        lvl31.addFileNode(new FileNode("32.txt", 8L, 16));
+
+        DirNode lvl32 = new DirNode("lvl3");
+        lvl32.addFileNode(new FileNode("33.txt", 16L, 24));
+
+        DirNode lvl2 = new DirNode("lvl2");
+        lvl2.addDirNode(lvl31);
+        lvl2.addDirNode(lvl32);
+        lvl2.addFileNode(new FileNode("34.dll", 24L, 32));
+
+        DirNode lvl1 = new DirNode("lvl1");
+        lvl1.addDirNode(lvl2);
+
+        RootNode rootNode = new RootNode();
+        rootNode.addDirNode(lvl1);
+        rootNode.addFileNode(new FileNode("35.lock", 32L, 40));
+
+        TreeLocatorEncoder treeLocatorEncoder = new TreeLocatorEncoder();
+        TreeLocatorDecoder treeLocatorDecoder = new TreeLocatorDecoder();
+        String encoded1 = treeLocatorEncoder.encode(rootNode);
+        RootNode decoded1 = treeLocatorDecoder.decode(encoded1);
+        String encoded2 = treeLocatorEncoder.encode(decoded1);
+        assertEquals(encoded1, encoded2);
+    }
+}