[test-improver] Add missing tests for DateUtils.isOverdue/isWithinRange/daysBetween and StringUtils.padRight

src/test/java/com/taskflow/util/DateUtilsTest.java

@@ -84,9 +84,68 @@ public void testStartOfDay() {
         // BUG: milliseconds not reset, but we don't test for it
     }
 
-    // Missing tests:
-    // - isOverdue
-    // - addBusinessDays
-    // - isWithinRange
-    // - edge cases (null inputs, boundary dates)
+    // --- isOverdue ---
+
+    @Test
+    public void testIsOverdue_pastDate() {
+        assertTrue(DateUtils.isOverdue("2020-01-01"));
+    }
+
+    @Test
+    public void testIsOverdue_futureDate() {
+        assertFalse(DateUtils.isOverdue("2099-12-31"));
+    }
+
+    @Test
+    public void testIsOverdue_null() {
+        // Null treated as not overdue (cannot distinguish from "no due date set")
+        assertFalse(DateUtils.isOverdue(null));
+    }
+
+    @Test
+    public void testIsOverdue_invalidDateString() {
+        // Unparseable date treated as not overdue (silent failure in parseDate)
+        assertFalse(DateUtils.isOverdue("not-a-date"));
+    }
+
+    // --- isWithinRange ---
+
+    @Test
+    public void testIsWithinRange_dateInMiddle() {
+        Date start  = new Date(1_000_000L);
+        Date middle = new Date(2_000_000L);
+        Date end    = new Date(3_000_000L);
+        assertTrue(DateUtils.isWithinRange(middle, start, end));
+    }
+
+    @Test
+    public void testIsWithinRange_dateBeforeStart() {
+        Date before = new Date(1_000_000L);
+        Date start  = new Date(2_000_000L);
+        Date end    = new Date(3_000_000L);
+        assertFalse(DateUtils.isWithinRange(before, start, end));
+    }
+
+    @Test
+    public void testIsWithinRange_dateAfterEnd() {
+        Date start = new Date(1_000_000L);
+        Date end   = new Date(2_000_000L);
+        Date after = new Date(3_000_000L);
+        assertFalse(DateUtils.isWithinRange(after, start, end));
+    }
+
+    // --- daysBetween (additional cases) ---
+
+    @Test
+    public void testDaysBetween_exactlyOneWeek() {
+        Date start = new Date(0L);
+        Date end   = new Date(7L * 24 * 60 * 60 * 1000);
+        assertEquals(7, DateUtils.daysBetween(start, end));
+    }
+
+    @Test
+    public void testDaysBetween_sameInstant() {
+        Date d = new Date(12_345_678L);
+        assertEquals(0, DateUtils.daysBetween(d, d));
+    }
 }

src/test/java/com/taskflow/util/StringUtilsTest.java

@@ -89,6 +89,31 @@ public void testJoin() {
         assertEquals("", StringUtils.join(null, ","));
         assertEquals("", StringUtils.join(new String[]{}, ","));
     }
-
-    // No test for padRight - it has a known StringIndexOutOfBoundsException bug
+
+    // --- padRight ---
+
+    @Test
+    public void testPadRight_stringShorterThanWidth() {
+        assertEquals("hi   ", StringUtils.padRight("hi", 5));
+    }
+
+    @Test
+    public void testPadRight_stringEqualsWidth() {
+        assertEquals("hello", StringUtils.padRight("hello", 5));
+    }
+
+    @Test
+    public void testPadRight_nullString() {
+        // null is treated as empty string, result is all-spaces padding
+        assertEquals("     ", StringUtils.padRight(null, 5));
+    }
+
+    @Test
+    public void testPadRight_stringLongerThanWidth_throwsBug() {
+        // Known bug (Issue #7): throws NegativeArraySizeException when str.length() > width
+        // Correct behavior should handle this gracefully (truncate or return as-is).
+        // When fixed, replace assertThrows with the expected output.
+        assertThrows(NegativeArraySizeException.class,
+                () -> StringUtils.padRight("hello world", 3));
+    }
 }