fix for calculus pisanus

see issue #461

Author: MenoData

i18n/src/main/java/net/time4j/history/HistoricIntegerElement.java

@@ -255,7 +255,7 @@ public Integer parse(
                     if (parsedResult != null) {
                         parsedResult.with(StdHistoricalElement.YEAR_OF_DISPLAY, yod);
                     }
-                } else if (Math.abs(yoe - yod) <= 1) { // check for plausibility
+                } else if (Math.abs(yoe - yod) <= 2) { // plausibility check (delta 2 necessary for calculus pisanus)
                     value = yoe;
                 } else { // now we have something else - let the formatter process the rest
                     value = yod;

i18n/src/test/java/net/time4j/history/EraFormatTest.java

@@ -480,4 +480,25 @@ public void parseFrance() throws ParseException {
             is(PlainDate.of(1565, 4, 3)));
     }
 
+    @Test
+    public void printPisa() {
+        ChronoFormatter<PlainDate> formatter =
+            ChronoFormatter.ofDatePattern("G-yyyy-MM-dd", PatternType.CLDR, new Locale("en", "IT", "PISA")).with(Leniency.STRICT);
+        assertThat(
+            formatter.format(PlainDate.of(1700, 1, 30)),
+            is("AD-1698/1700-01-30"));
+    }
+
+    @Test
+    public void parsePisa() throws ParseException {
+        ChronoFormatter<PlainDate> formatter =
+            ChronoFormatter.ofDatePattern("G-yyyy-MM-dd", PatternType.CLDR, new Locale("en", "IT", "PISA")).with(Leniency.STRICT);
+        assertThat(
+            formatter.parse("AD-1698/1700-01-30"),
+            is(PlainDate.of(1700, 1, 30)));
+        assertThat(
+            formatter.parse("AD-1700-01-30"),
+            is(PlainDate.of(1700, 1, 30)));
+    }
+
 }