Add tests for iteration and control statements (#28)

Author: mperor

basics/src/test/java/pl/mperor/lab/java/data/type/ArraysTest.java

@@ -23,7 +23,7 @@ public void testMultiDimensionalArray() {
 
     @Test
     public void testSquareMatrix() {
-        int[][] multi = new int[2][2];
-        Assertions.assertArrayEquals(new int[][]{{0, 0}, {0, 0}}, multi);
+        int[][] matrix = new int[2][2];
+        Assertions.assertArrayEquals(new int[][]{{0, 0}, {0, 0}}, matrix);
     }
 }

basics/src/test/java/pl/mperor/lab/java/statement/ControlStatementTest.java

@@ -0,0 +1,46 @@
+package pl.mperor.lab.java.statement;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+public class ControlStatementTest {
+
+    @Test
+    public void testIfElseStatement() {
+        Assertions.assertEquals(1, defaultIfNull(null, 1));
+        Assertions.assertEquals(-1, defaultIfNull(-1, 1));
+    }
+
+    public static <T> T defaultIfNull(T nullable, T ifNull) {
+        if (nullable != null) {
+            return nullable;
+        }
+
+        return ifNull;
+    }
+
+    @Test
+    public void testSwitchBlock() {
+        Assertions.assertEquals(2, calculateByOperator("+", 1, 1));
+        Assertions.assertEquals(0, calculateByOperator("-", 1, 1));
+        Assertions.assertEquals(4, calculateByOperator("*", 2, 2));
+        Assertions.assertEquals(2, calculateByOperator("/", 4, 2));
+        Assertions.assertThrows(IllegalStateException.class, () -> calculateByOperator("?", 1, 1));
+    }
+
+    public static int calculateByOperator(String operator, int a, int b) {
+        switch (operator) {
+            case "+":
+                return a + b;
+            case "-":
+                return a - b;
+            case "*":
+                return a * b;
+            case "/":
+                return b != 0 ? a / b : 0;
+            default:
+                throw new IllegalStateException("Invalid operator: " + operator);
+        }
+    }
+
+}

basics/src/test/java/pl/mperor/lab/java/statement/IterationStatementTest.java

@@ -0,0 +1,123 @@
+package pl.mperor.lab.java.statement;
+
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import java.io.ByteArrayOutputStream;
+import java.io.OutputStream;
+import java.io.PrintStream;
+import java.util.List;
+
+public class IterationStatementTest {
+
+    private PrintStream original = System.out;
+    private OutputStream out;
+
+    @BeforeEach
+    void setUp() {
+        out = new ByteArrayOutputStream();
+        System.setOut(new PrintStream(out));
+    }
+
+    @AfterEach
+    void tearDown() {
+        System.setOut(original);
+    }
+
+    @Test
+    public void testWhileLoop() {
+        var integers = List.of(1, 2, 3);
+        var iterator = integers.iterator();
+        while (iterator.hasNext()) {
+            System.out.print(iterator.next());
+        }
+        Assertions.assertEquals("123", out.toString());
+    }
+
+    @Test
+    public void testDoWhileLoop() {
+        var connector = new FaultyConnector();
+        do {
+            connector.reset();
+        } while (!connector.connect());
+        Assertions.assertEquals(2, connector.resetCounter);
+    }
+
+    static class FaultyConnector {
+        int doubleResetNeeded = 2;
+        int resetCounter = 0;
+
+        boolean connect() {
+            return resetCounter >= doubleResetNeeded;
+        }
+
+        void reset() {
+            resetCounter++;
+        }
+    }
+
+    @Test
+    public void testForLoop() {
+        int[] integers = {1, 2, 3};
+        for (int i = 0; i < integers.length; i++) {
+            System.out.printf("(%d->%d)", i, integers[i]);
+        }
+        Assertions.assertEquals("(0->1)(1->2)(2->3)", out.toString());
+    }
+
+    @Test
+    public void testEnhancedForLoopAkaForEachLoop() {
+        var integers = List.of(1, 2, 3);
+        for (Integer integer : integers) {
+            System.out.print(integer);
+        }
+        Assertions.assertEquals("123", out.toString());
+    }
+
+    @Test
+    public void testJumpStatements() {
+        breakFromInfiniteLoop();
+        printEvenNumbers(1, 2, 3, 4);
+        Assertions.assertEquals("24", out.toString());
+    }
+
+    private void breakFromInfiniteLoop() {
+        for (; ; ) {
+            break;
+        }
+    }
+
+    private void printEvenNumbers(int... numbers) {
+        for (int number : numbers) {
+            if (number % 2 != 0) {
+                continue;
+            }
+            System.out.print(number);
+        }
+    }
+
+    @Test
+    public void testNestedLoop() {
+        record Point(int x, int y) {
+            @Override
+            public String toString() {
+                return "" + x + y;
+            }
+        }
+        Point[][] matrix = {
+                {new Point(0, 0), new Point(0, 1)},
+                {new Point(1, 0), new Point(1, 1)}
+        };
+
+        for (int row = 0; row < matrix.length; row++) {
+            for (int col = 0; col < matrix[row].length; col++) {
+                System.out.printf("(%s)", matrix[row][col]);
+            }
+        }
+
+        Assertions.assertEquals("(00)(01)(10)(11)", out.toString());
+    }
+
+}