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https://github.com/TheAlgorithms/Java.git
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testing: improve test coverage NodeStackTest (#6432)
* testing: improve test coverage NodeStackTest * style: fix style issues * testing: fix type * testing: fix import * testing: fix import
This commit is contained in:
Oleksandr Klymenko
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GitHub
GitHub
parent
fc07cd806e
commit
edb8167374
@@ -1,15 +1,26 @@
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package com.thealgorithms.datastructures.stacks;
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import static org.junit.jupiter.api.Assertions.assertEquals;
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import static org.junit.jupiter.api.Assertions.assertFalse;
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import static org.junit.jupiter.api.Assertions.assertThrows;
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import static org.junit.jupiter.api.Assertions.assertTrue;
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import org.junit.jupiter.api.BeforeEach;
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import org.junit.jupiter.api.DisplayName;
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import org.junit.jupiter.api.Test;
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class NodeStackTest {
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private NodeStack<Integer> intStack;
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private NodeStack<String> stringStack;
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@BeforeEach
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void setUp() {
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intStack = new NodeStack<>();
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stringStack = new NodeStack<>();
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}
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@Test
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@DisplayName("Test push operation")
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void testPush() {
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NodeStack<Integer> stack = new NodeStack<>();
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stack.push(10);
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@@ -18,6 +29,7 @@ class NodeStackTest {
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}
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@Test
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@DisplayName("Test pop operation")
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void testPop() {
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NodeStack<String> stack = new NodeStack<>();
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stack.push("First");
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@@ -27,12 +39,14 @@ class NodeStackTest {
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}
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@Test
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@DisplayName("Test pop on empty stack throws exception")
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void testPopOnEmptyStack() {
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NodeStack<Double> stack = new NodeStack<>();
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assertThrows(IllegalStateException.class, stack::pop, "Popping an empty stack should throw IllegalStateException.");
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}
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@Test
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@DisplayName("Test peek operation")
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void testPeek() {
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NodeStack<Integer> stack = new NodeStack<>();
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stack.push(5);
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@@ -43,22 +57,25 @@ class NodeStackTest {
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}
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@Test
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@DisplayName("Test peek on empty stack throws exception")
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void testPeekOnEmptyStack() {
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NodeStack<String> stack = new NodeStack<>();
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assertThrows(IllegalStateException.class, stack::peek, "Peeking an empty stack should throw IllegalStateException.");
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}
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@Test
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@DisplayName("Test isEmpty method")
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void testIsEmpty() {
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NodeStack<Character> stack = new NodeStack<>();
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assertTrue(stack.isEmpty(), "Newly initialized stack should be empty.");
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stack.push('A');
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assertFalse(stack.isEmpty(), "Stack should not be empty after a push operation.");
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org.junit.jupiter.api.Assertions.assertFalse(stack.isEmpty(), "Stack should not be empty after a push operation.");
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stack.pop();
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assertTrue(stack.isEmpty(), "Stack should be empty after popping the only element.");
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}
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@Test
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@DisplayName("Test size method")
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void testSize() {
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NodeStack<Integer> stack = new NodeStack<>();
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assertEquals(0, stack.size(), "Size of empty stack should be 0.");
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@@ -70,4 +87,164 @@ class NodeStackTest {
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stack.pop();
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assertEquals(0, stack.size(), "Size should be 0 after popping all elements.");
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}
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@Test
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@DisplayName("Test push and pop with null values")
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void testPushPopWithNull() {
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stringStack.push(null);
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stringStack.push("not null");
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stringStack.push(null);
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assertEquals(3, stringStack.size(), "Stack should contain 3 elements including nulls");
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org.junit.jupiter.api.Assertions.assertNull(stringStack.pop(), "Should pop null value");
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assertEquals("not null", stringStack.pop(), "Should pop 'not null' value");
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org.junit.jupiter.api.Assertions.assertNull(stringStack.pop(), "Should pop null value");
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assertTrue(stringStack.isEmpty(), "Stack should be empty after popping all elements");
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}
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@Test
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@DisplayName("Test LIFO (Last In First Out) behavior")
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void testLifoBehavior() {
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int[] values = {1, 2, 3, 4, 5};
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// Push values in order
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for (int value : values) {
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intStack.push(value);
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}
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// Pop values should be in reverse order
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for (int i = values.length - 1; i >= 0; i--) {
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assertEquals(values[i], intStack.pop(), "Elements should be popped in LIFO order");
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}
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}
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@Test
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@DisplayName("Test peek doesn't modify stack")
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void testPeekDoesNotModifyStack() {
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intStack.push(1);
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intStack.push(2);
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intStack.push(3);
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int originalSize = intStack.size();
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int peekedValue = intStack.peek();
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assertEquals(3, peekedValue, "Peek should return top element");
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assertEquals(originalSize, intStack.size(), "Peek should not change stack size");
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assertEquals(3, intStack.peek(), "Multiple peeks should return same value");
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org.junit.jupiter.api.Assertions.assertFalse(intStack.isEmpty(), "Peek should not make stack empty");
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}
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@Test
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@DisplayName("Test mixed push and pop operations")
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void testMixedOperations() {
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// Test interleaved push/pop operations
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intStack.push(1);
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assertEquals(1, intStack.pop());
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assertTrue(intStack.isEmpty());
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intStack.push(2);
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intStack.push(3);
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assertEquals(3, intStack.pop());
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intStack.push(4);
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assertEquals(4, intStack.peek());
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assertEquals(2, intStack.size());
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assertEquals(4, intStack.pop());
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assertEquals(2, intStack.pop());
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assertTrue(intStack.isEmpty());
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}
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@Test
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@DisplayName("Test stack with duplicate values")
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void testStackWithDuplicates() {
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intStack.push(1);
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intStack.push(1);
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intStack.push(1);
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assertEquals(3, intStack.size(), "Stack should handle duplicate values");
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assertEquals(1, intStack.peek(), "Peek should return duplicate value");
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assertEquals(1, intStack.pop(), "Should pop first duplicate");
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assertEquals(1, intStack.pop(), "Should pop second duplicate");
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assertEquals(1, intStack.pop(), "Should pop third duplicate");
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assertTrue(intStack.isEmpty(), "Stack should be empty after popping all duplicates");
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}
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@Test
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@DisplayName("Test stack with different data types")
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void testDifferentDataTypes() {
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NodeStack<Character> charStack = new NodeStack<>();
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NodeStack<Boolean> booleanStack = new NodeStack<>();
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// Test with Character
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charStack.push('A');
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charStack.push('Z');
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assertEquals('Z', charStack.peek(), "Should handle Character values");
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// Test with Boolean
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booleanStack.push(Boolean.TRUE);
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booleanStack.push(Boolean.FALSE);
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assertEquals(Boolean.FALSE, booleanStack.peek(), "Should handle Boolean values");
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}
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@Test
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@DisplayName("Test stack state consistency after exceptions")
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void testStateConsistencyAfterExceptions() {
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// Stack should remain consistent after exception-throwing operations
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intStack.push(1);
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intStack.push(2);
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// Try to peek and pop normally first
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assertEquals(2, intStack.peek());
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assertEquals(2, intStack.pop());
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assertEquals(1, intStack.size());
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// Pop remaining element
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assertEquals(1, intStack.pop());
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assertTrue(intStack.isEmpty());
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// Now stack is empty, operations should throw exceptions
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assertThrows(IllegalStateException.class, intStack::peek);
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assertThrows(IllegalStateException.class, intStack::pop);
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// Stack should still be in valid empty state
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assertTrue(intStack.isEmpty());
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assertEquals(0, intStack.size());
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// Should be able to push after exceptions
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intStack.push(3);
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org.junit.jupiter.api.Assertions.assertFalse(intStack.isEmpty());
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assertEquals(1, intStack.size());
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assertEquals(3, intStack.peek());
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}
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@Test
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@DisplayName("Test single element stack operations")
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void testSingleElementStack() {
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intStack.push(2);
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org.junit.jupiter.api.Assertions.assertFalse(intStack.isEmpty(), "Stack with one element should not be empty");
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assertEquals(1, intStack.size(), "Size should be 1");
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assertEquals(2, intStack.peek(), "Peek should return the single element");
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assertEquals(1, intStack.size(), "Peek should not change size");
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assertEquals(2, intStack.pop(), "Pop should return the single element");
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assertTrue(intStack.isEmpty(), "Stack should be empty after popping single element");
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assertEquals(0, intStack.size(), "Size should be 0 after popping single element");
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}
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@Test
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@DisplayName("Test toString method if implemented")
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void testToString() {
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// This test assumes NodeStack has a toString method
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// If not implemented, this test can be removed or NodeStack can be enhanced
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intStack.push(1);
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intStack.push(2);
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intStack.push(3);
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String stackString = intStack.toString();
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// Basic check that toString doesn't throw exception and returns something
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assertTrue(stackString != null, "toString should not return null");
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assertTrue(stackString.length() > 0, "toString should return non-empty string");
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}
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}
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