feat: allow 1s tolerance for media overlays duration sum check

Fix #1328

Author: rdeltour

src/main/java/com/adobe/epubcheck/opf/OPFChecker30.java

@@ -439,7 +439,7 @@ private void checkMediaOverlaysDuration()
           }
         }
         // report if the sum and total don't match
-        if (!totalDuration.equals(sumDuration))
+        if (!totalDuration.eqWithinTolerance(sumDuration, 1000))
         {
           report.message(MessageId.MED_016, EPUBLocation.of(context));
         }

src/test/resources/epub3/09-media-overlays/files/mediaoverlays-duration-total-not-sum-warning.opf

@@ -9,7 +9,7 @@
         <!-- Media Overlays Duration Properties -->
         <meta property="media:duration">10min</meta>
         <meta refines="#mo001" property="media:duration">5min</meta>
-        <meta refines="#mo002" property="media:duration">0:05:00.200</meta>
+        <meta refines="#mo002" property="media:duration">0:05:01.100</meta>
     </metadata>
     <manifest>
         <item id="t001" href="contents.xhtml" properties="nav" media-type="application/xhtml+xml"/>

src/test/resources/epub3/09-media-overlays/files/mediaoverlays-duration-total-within-tolerance-valid.opf

@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<package xmlns="http://www.idpf.org/2007/opf" version="3.0" unique-identifier="uid"
+    xmlns:dc="http://purl.org/dc/elements/1.1/">
+    <metadata>
+        <dc:title>Title</dc:title>
+        <dc:language>en</dc:language>
+        <dc:identifier id="uid">NOID</dc:identifier>
+        <meta property="dcterms:modified">2019-01-01T12:00:00Z</meta>
+        <!-- Media Overlays Duration Properties -->
+        <meta property="media:duration">10min</meta>
+        <meta refines="#mo001" property="media:duration">5min</meta>
+        <meta refines="#mo002" property="media:duration">0:05:00.500</meta>
+    </metadata>
+    <manifest>
+        <item id="t001" href="contents.xhtml" properties="nav" media-type="application/xhtml+xml"/>
+        <item id="mo001" href="mediaoverlay_001.smil" media-type="application/smil+xml"/>
+        <item id="mo002" href="mediaoverlay_002.smil" media-type="application/smil+xml"/>
+    </manifest>
+    <spine>
+        <itemref idref="t001"/>
+    </spine>
+</package>

src/test/resources/epub3/09-media-overlays/media-overlays.feature

@@ -316,7 +316,13 @@ Feature: EPUB 3 — Media Overlays
     And the message contains "item media:duration meta element not set"
     And no other errors or warnings are reported
 
+  @spec @xref:sec-mo-package-metadata
   Scenario: the total duration should be the sum of all Media Overlay durations
     When checking file 'mediaoverlays-duration-total-not-sum-warning.opf'
     Then warning MED-016 is reported
     And no other errors or warnings are reported
+
+  @spec @xref:sec-mo-package-metadata
+  Scenario: the total duration has a 1s tolerance
+    When checking file 'mediaoverlays-duration-total-within-tolerance-valid.opf'
+    Then no errors or warnings are reported