Add test for MultiBucketStrategy class

src/main/java/jenkins/advancedqueue/sorter/strategy/MultiBucketStrategy.java

@@ -95,8 +95,9 @@ private ListBoxModel internalFillDefaultPriorityItems(int value) {
             return items;
         }
 
+        /* package-protected for testing */
         @CheckForNull
-        private MultiBucketStrategy getStrategy() {
+        MultiBucketStrategy getStrategy() {
             SorterStrategy strategy = PrioritySorterConfiguration.get().getStrategy();
             if (strategy == null || !(strategy instanceof MultiBucketStrategy)) {
                 return null;

src/test/java/jenkins/advancedqueue/sorter/strategy/MultiBucketStrategyTest.java

@@ -0,0 +1,109 @@
+package jenkins.advancedqueue.sorter.strategy;
+
+import static org.junit.Assert.assertEquals;
+
+import edu.umd.cs.findbugs.annotations.NonNull;
+import hudson.model.Queue;
+import hudson.util.ListBoxModel;
+import jenkins.advancedqueue.sorter.SorterStrategyCallback;
+import org.junit.Before;
+import org.junit.ClassRule;
+import org.junit.Test;
+import org.jvnet.hudson.test.JenkinsRule;
+
+public class MultiBucketStrategyTest extends MultiBucketStrategy {
+
+    /** @{inheritDoc} */
+    @Override
+    public SorterStrategyCallback onNewItem(@NonNull Queue.Item item, SorterStrategyCallback weightCallback) {
+        return weightCallback;
+    }
+
+    @ClassRule
+    public static JenkinsRule j = new JenkinsRule();
+
+    private static MultiBucketStrategy strategy;
+    private static MultiBucketStrategy.MultiBucketStrategyDescriptor descriptor;
+    private static final int TEST_PRIORITY_COUNT = 10;
+    private static final int TEST_PRIORITY_DEFAULT = 5;
+
+    @Before
+    public void setUp() {
+        strategy = new MultiBucketStrategy(TEST_PRIORITY_COUNT, TEST_PRIORITY_DEFAULT) {
+            @Override
+            public SorterStrategyCallback onNewItem(@NonNull Queue.Item item, SorterStrategyCallback weightCallback) {
+                return weightCallback;
+            }
+        };
+
+        descriptor = new MultiBucketStrategy.MultiBucketStrategyDescriptor() {
+            @Override
+            public String getShortName() {
+                return "";
+            }
+
+            @Override
+            protected MultiBucketStrategy getStrategy() {
+                return strategy;
+            }
+        };
+    }
+
+    @Test
+    public void getNumberOfPrioritiesReturnsCorrectValue() {
+        assertEquals(TEST_PRIORITY_COUNT, strategy.getNumberOfPriorities());
+    }
+
+    @Test
+    public void getDefaultPriorityReturnsCorrectValue() {
+        assertEquals(TEST_PRIORITY_DEFAULT, strategy.getDefaultPriority());
+    }
+
+    @Test
+    public void doFillDefaultPriorityItemsReturnsCorrectItems() {
+        ListBoxModel items = descriptor.doFillDefaultPriorityItems();
+        assertEquals(TEST_PRIORITY_COUNT, items.size());
+        for (int i = 0; i < TEST_PRIORITY_COUNT; i++) {
+            assertEquals(String.valueOf(i + 1), items.get(i).value);
+        }
+    }
+
+    @Test
+    public void doUpdateDefaultPriorityItemsHandlesInvalidInput() {
+        ListBoxModel items = descriptor.doUpdateDefaultPriorityItems("invalid");
+        assertEquals(MultiBucketStrategy.DEFAULT_PRIORITY, items.size());
+        for (int i = 0; i < MultiBucketStrategy.DEFAULT_PRIORITY; i++) {
+            assertEquals(String.valueOf(i + 1), items.get(i).value);
+        }
+    }
+
+    @Test
+    public void doUpdateDefaultPriorityItemsHandlesValidInput() {
+        ListBoxModel items = descriptor.doUpdateDefaultPriorityItems("3");
+        assertEquals(3, items.size());
+        for (int i = 0; i < 3; i++) {
+            assertEquals(String.valueOf(i + 1), items.get(i).value);
+        }
+    }
+
+    @Test
+    public void doUpdateDefaultPriorityItemsHandlesNegativeInput() {
+        ListBoxModel items = descriptor.doUpdateDefaultPriorityItems("-1");
+        assertEquals(0, items.size());
+    }
+
+    @Test
+    public void doUpdateDefaultPriorityItemsHandlesZeroInput() {
+        ListBoxModel items = descriptor.doUpdateDefaultPriorityItems("0");
+        assertEquals(0, items.size());
+    }
+
+    @Test
+    public void doUpdateDefaultPriorityItemsHandlesLargeInput() {
+        ListBoxModel items = descriptor.doUpdateDefaultPriorityItems("100");
+        assertEquals(100, items.size());
+        for (int i = 0; i < 100; i++) {
+            assertEquals(String.valueOf(i + 1), items.get(i).value);
+        }
+    }
+}