Add a test.

Author: Gary Gregory

src/test/java/org/apache/commons/io/IOUtilsTestCase.java

@@ -1475,6 +1475,16 @@ public void testToByteArray_InputStream_SizeZero() throws Exception {
         }
     }
 
+    @Test
+    public void testToByteArray_InputStream_SizeOne() throws Exception {
+
+        try (FileInputStream fin = new FileInputStream(m_testFile)) {
+            final byte[] out = IOUtils.toByteArray(fin, 1);
+            assertNotNull(out, "Out cannot be null");
+            assertEquals(1, out.length, "Out length must be 1");
+        }
+    }
+
     @Test
     public void testToByteArray_Reader() throws IOException {
         final String charsetName = "UTF-8";