test: add tests for MyListCollector

app/src/test/java/ru/project/MyListCollectorTest.java

@@ -0,0 +1,63 @@
+package ru.test.maven.spring;
+import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.*;
+import java.util.Set;
+import java.util.stream.Collector;
+import java.util.stream.IntStream;
+import java.util.Collections;
+public class MyListCollectorTest
+{
+    private final MyListCollector<Integer> collector = new MyListCollector<>();
+
+    @Test
+    void shouldTestCollectInOrderSequential() {
+        MyList<Integer> result = IntStream.range(0, 10)
+                .boxed()
+                .collect(MyCollectors.toMyList());
+
+        assertEquals(10, result.size());
+        for (int i = 0; i < result.size(); i++) {
+            assertEquals(i, (int) result.get(i));
+        }
+
+    }
+
+    @Test
+    void shouldTestCollectInOrderParallel() {
+        MyList<Integer> result = IntStream.range(0, 100)
+                .parallel()
+                .boxed()
+                .collect(MyCollectors.toMyList());
+
+        assertEquals(100, result.size());
+        for (int i = 0; i < result.size(); i++) {
+            assertEquals(i, (int) result.get(i));
+        }
+    }
+
+    @Test
+    void shouldTestHandleEmptyStream() {
+        MyList<Integer> result = IntStream.empty()
+                .boxed()
+                .collect(MyCollectors.toMyList());
+
+        assertTrue(result.isEmpty());
+
+    }
+    @Test
+    void shouldTestNotUseStandardList() {
+        MyList<String> result = IntStream.range(0, 5)
+                .mapToObj(i -> "item" + i)
+                .collect(MyCollectors.toMyList());
+
+        assertInstanceOf(MyList.class, result);
+        assertFalse(result instanceof java.util.List);
+    }
+    @Test
+    void shouldTestHaveCorrectCharacteristics() {
+        Set<Collector.Characteristics> characteristics = collector.characteristics();
+        assertTrue(characteristics.contains(java.util.stream.Collector.Characteristics.IDENTITY_FINISH));
+        assertFalse(characteristics.contains(java.util.stream.Collector.Characteristics.UNORDERED));
+    }
+
+}