Java/src/test/java/com/thealgorithms/datastructures/trees/CheckBinaryTreeIsValidBSTTest.java at master · TheAlgorithms/Java · GitHub

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packagecom.thealgorithms.datastructures.trees;

importstaticorg.junit.jupiter.api.Assertions.assertFalse;
importstaticorg.junit.jupiter.api.Assertions.assertTrue;

importorg.junit.jupiter.api.Test;

/**
 * @author Albina Gimaletdinova on 17/02/2023
 */
publicclassCheckBinaryTreeIsValidBSTTest {
@Test
publicvoidtestRootNull() {
assertTrue(CheckBinaryTreeIsValidBST.isBST(null));
 }

@Test
publicvoidtestOneNode() {
finalBinaryTree.Noderoot = TreeTestUtils.createTree(newInteger[] {Integer.MIN_VALUE});
assertTrue(CheckBinaryTreeIsValidBST.isBST(root));
 }

/*
 9
 / \
 7 13
 /\ / \
 3 8 10 20
 */
@Test
publicvoidtestBinaryTreeIsBST() {
finalBinaryTree.Noderoot = TreeTestUtils.createTree(newInteger[] {9, 7, 13, 3, 8, 10, 20});
assertTrue(CheckBinaryTreeIsValidBST.isBST(root));
 }

/*
 9
 / \
 7 13
 /\ / \
 3 8 10 13 <--- duplicated node
 */
@Test
publicvoidtestBinaryTreeWithDuplicatedNodesIsNotBST() {
finalBinaryTree.Noderoot = TreeTestUtils.createTree(newInteger[] {9, 7, 13, 3, 8, 10, 13});
assertFalse(CheckBinaryTreeIsValidBST.isBST(root));
 }

/*
 9
 / \
 7 13
 /\ / \
 3 8 10 12 <---- violates BST rule, needs to be more than 13 (parent node)
 */
@Test
publicvoidtestBinaryTreeIsNotBST() {
finalBinaryTree.Noderoot = TreeTestUtils.createTree(newInteger[] {9, 7, 13, 3, 8, 10, 12});
assertFalse(CheckBinaryTreeIsValidBST.isBST(root));
 }
}