Increase test coverage (fixes #3895 #3896) (#3897)

src/test/java/com/thealgorithms/datastructures/trees/BinaryTreeTest.java

@@ -0,0 +1,78 @@
+package com.thealgorithms.datastructures.trees;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class BinaryTreeTest {
+
+    //checks that adding populating the tree and searching for data
+    //retrieves the expected data
+@Test
+void test1(){
+    BinaryTree t = new BinaryTree();
+    t.put(3);
+    t.put(5);
+    t.put(7);
+    t.put(9);
+    t.put(12);
+    
+
+    assertEquals(t.find(5).data, 5);
+    assertEquals(t.find(7).data, 7);
+}
+
+    //checks that removing data from the tree
+    //properly removes and makes the new root the expected new root
+@Test
+void test2(){
+    BinaryTree t = new BinaryTree();
+    t.put(3);
+    t.put(5);
+    t.put(7);
+    t.put(9);
+    t.put(12);
+    t.remove(3);
+    t.remove(5);
+    t.remove(7);
+    
+
+    assertEquals(t.getRoot().data, 9);
+}
+
+//checks that removing an unexistend node returns false
+// as specified by the documentation of the function
+@Test
+void test3(){
+    BinaryTree t = new BinaryTree();
+    t.put(3);
+    t.put(5);
+    t.put(7);
+    t.put(9);
+    t.put(12);
+
+    assertEquals(t.remove(9), true);
+    assertEquals(t.remove(398745987), false);
+}
+
+//check if the bfs, inOrder, preOrder and postOrder functions
+//worg as expected, also increases the coverage measures in
+//JaCoCo
+@Test
+void test4(){
+    BinaryTree t = new BinaryTree();
+    t.put(3);
+    t.put(5);
+    t.put(7);
+    t.put(9);
+    t.put(12);
+
+    t.bfs(t.find(12));
+    t.inOrder(t.getRoot());
+    t.preOrder(t.getRoot());
+    t.postOrder(t.getRoot());
+
+    assertEquals(t.remove(9), true);
+    assertEquals(t.remove(398745987), false);
+}
+}