Fix incorrect month lengths in algorihmic converter

And test sanity of day of month and months length for all the calendars we have.
persian-calendar · Oct 20, 2021 · 89db005 · 89db005
1 parent 7ec02bb
commit 89db005
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Showing 2 changed files with 38 additions and 13 deletions.
diff --git a/src/main/java/io/github/persiancalendar/calendar/persian/AlgorithmicConverter.java b/src/main/java/io/github/persiancalendar/calendar/persian/AlgorithmicConverter.java
@@ -56,12 +56,13 @@ public static long toJdn(int year, int month, int day) {
     }
 
     public static int[] fromJdn(long jdn) {
+        jdn++; // TODO: Investigate why this is needed
         long yearStart = persianNewYearOnOrBefore(jdn - projectJdnOffset);
         int y = (int) (Math.floor(((yearStart - persianEpoch) / meanTropicalYearInDays) + 0.5)) + 1;
 
         int ordinalDay = (int) (jdn - toJdn(y, 1, 1));
         int m = monthFromOrdinalDay(ordinalDay);
-        int d = ordinalDay - daysInPreviousMonths(m) + 1; // TODO: The original one didn't need +1, see why is needed now
+        int d = ordinalDay - daysInPreviousMonths(m);
         return new int[]{y, m, d};
     }
 

diff --git a/src/test/kotlin/io/github/persiancalendar/calendar/MainTests.kt b/src/test/kotlin/io/github/persiancalendar/calendar/MainTests.kt
@@ -125,34 +125,58 @@ class MainTests {
         )
     }
 
+    private val startJdn = CivilDate(1250, 1, 1).toJdn()
+    private val endJdn = CivilDate(2350, 1, 1).toJdn()
+
     @Test
     fun `Practice Persian converting back and forth`() {
         assertEquals(PersianDate(1398, 1, 1).toJdn(), 2458564)
-        val startJdn = CivilDate(1750, 1, 1).toJdn()
-        val endJdn = CivilDate(2350, 1, 1).toJdn()
-        (startJdn..endJdn).forEach { assertEquals(it, PersianDate(it).toJdn()) }
+        (startJdn..endJdn).map {
+            val date = PersianDate(it)
+            assertEquals(it, date.toJdn())
+            assertTrue(date.month in 1..12)
+            assertTrue(date.dayOfMonth in 1..if (date.month in 1..6) 31 else 30)
+            date.dayOfMonth
+        }.ensureContinuity()
     }
 
     @Test
     fun `Practice Islamic converting back and forth`() {
-        val startJdn = CivilDate(1750, 1, 1).toJdn()
-        val endJdn = CivilDate(2350, 1, 1).toJdn()
-        (startJdn..endJdn).forEach { assertEquals(it, IslamicDate(it).toJdn()) }
+        (startJdn..endJdn).map {
+            val date = IslamicDate(it)
+            assertEquals(it, date.toJdn())
+            assertTrue(date.month in 1..12)
+            assertTrue(date.dayOfMonth in 1..30)
+            date.dayOfMonth
+        }.ensureContinuity()
     }
 
     @Test
     fun `Practice UmmAlqara converting back and forth`() {
         IslamicDate.useUmmAlQura = true
-        val startJdn = CivilDate(1750, 1, 1).toJdn()
-        val endJdn = CivilDate(2350, 1, 1).toJdn()
-        (startJdn..endJdn).forEach { assertEquals(it, IslamicDate(it).toJdn()) }
+        (startJdn..endJdn).map {
+            val date = IslamicDate(it)
+            assertEquals(it, date.toJdn())
+            assertTrue(date.month in 1..12)
+            assertTrue(date.dayOfMonth in 1..30)
+            date.dayOfMonth
+        }.ensureContinuity()
         IslamicDate.useUmmAlQura = false
     }
 
     @Test
     fun `Practice Gregorian converting back and forth`() {
-        val startJdn = CivilDate(1750, 1, 1).toJdn()
-        val endJdn = CivilDate(2350, 1, 1).toJdn()
-        (startJdn..endJdn).forEach { assertEquals(it, CivilDate(it).toJdn()) }
+        (startJdn..endJdn).map {
+            val date = CivilDate(it)
+            assertEquals(it, date.toJdn())
+            assertTrue(date.month in 1..12)
+            assertTrue(date.dayOfMonth in 1..31)
+            date.dayOfMonth
+        }.ensureContinuity()
     }
+
+    private fun List<Int>.ensureContinuity() = this.reduce { previousDayOfMonth, dayOfMonth ->
+        assertTrue(dayOfMonth == 1 || dayOfMonth == previousDayOfMonth + 1)
+        dayOfMonth
+    }.let {}
 }