Astronomy Engine v2.1.7: eclipse obscuration

This is my second attempt to release eclipse obscuration.
I discovered there was a missing unit test for obscuration
for lunar eclipses in the Kotlin library. It has been added.

Author: cosinekitty

Diff for: README.md

@@ -10,7 +10,7 @@
         </td>
         <td style="text-align: center;"><a href="demo/c/">Examples</a></td>
         <td style="text-align: center;">
-            <div><a href="source/c/"><img src="https://img.shields.io/badge/C%20%2f%20C%2b%2b-v2.1.6-blue" /></a></div>
+            <div><a href="source/c/"><img src="https://img.shields.io/badge/C%20%2f%20C%2b%2b-v2.1.7-blue" /></a></div>
             <div><a href="source/c/">Code &amp; Docs</a></div>
         </td>
     </tr>

Diff for: generate/version.txt

@@ -1 +1 @@
-2.1.6
+2.1.7

Diff for: source/csharp/astronomy.csproj

@@ -4,7 +4,7 @@
       <GenerateDocumentationFile>true</GenerateDocumentationFile>
       <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
       <PackageId>CosineKitty.AstronomyEngine</PackageId>
-      <PackageVersion>2.1.6</PackageVersion>
+      <PackageVersion>2.1.7</PackageVersion>
       <RepositoryUrl>https://github.com/cosinekitty/astronomy</RepositoryUrl>
       <Authors>Don Cross</Authors>
       <Title>Astronomy Engine</Title>

Diff for: source/js/package.json

@@ -1,6 +1,6 @@
 {
   "name": "astronomy-engine",
-  "version": "2.1.6",
+  "version": "2.1.7",
   "description": "Astronomy calculation for Sun, Moon, and planets.",
   "main": "./astronomy.js",
   "module": "./esm/astronomy.js",

Diff for: source/kotlin/README.md

@@ -25,7 +25,7 @@ allprojects {
 Now add the dependency:
 ```kotlin
 dependencies {
-    implementation("io.github.cosinekitty:astronomy:2.1.6")
+    implementation("io.github.cosinekitty:astronomy:2.1.7")
 }
 ```
 

Diff for: source/kotlin/build.gradle.kts

@@ -6,7 +6,7 @@ plugins {
 }
 
 group = "io.github.cosinekitty"
-version = "2.1.6"
+version = "2.1.7"
 
 repositories {
     mavenCentral()

Diff for: source/kotlin/src/test/kotlin/io/github/cosinekitty/astronomy/Tests.kt

@@ -1680,9 +1680,40 @@ class Tests {
 
     //----------------------------------------------------------------------------------------
 
+    private fun lunarFractionCase(year: Int, month: Int, day: Int, obscuration: Double) {
+        // Search for the first lunar eclipse to occur after the given date.
+        val time = Time(year, month, day, 0, 0, 0.0)
+        val eclipse = searchLunarEclipse(time)
+
+        // This should be a partial lunar eclipse.
+        assertTrue(eclipse.kind == EclipseKind.Partial, "$time: expected partial eclipse, but found ${eclipse.kind}")
+
+        // The partial eclipse should always happen within 24 hours of the given date.
+        val dt = eclipse.peak.ut - time.ut
+        assertTrue(dt >= 0.0 && dt <= 1.0, "$time: eclipse occurs $dt days after the search time.")
+
+        val diff = eclipse.obscuration - obscuration
+        assertTrue(abs(diff) < 0.00763, "$time: obscuration error = $diff, expected $obscuration, found ${eclipse.obscuration}")
+    }
+
     @Test
     fun `Lunar eclipse obscuration`() {
-
+        // Verify calculation of the fraction of the Moon's disc covered by the Earth's umbra during a partial eclipse.
+        // Data for this is more tedious to gather, because Espenak data does not contain it.
+        // We already verify fraction=0.0 for penumbral eclipses and fraction=1.0 for total eclipses in LunarEclipseTest.
+
+        lunarFractionCase(2010,  6, 26, 0.506)  // https://www.timeanddate.com/eclipse/lunar/2010-june-26
+        lunarFractionCase(2012,  6,  4, 0.304)  // https://www.timeanddate.com/eclipse/lunar/2012-june-4
+        lunarFractionCase(2013,  4, 25, 0.003)  // https://www.timeanddate.com/eclipse/lunar/2013-april-25
+        lunarFractionCase(2017,  8,  7, 0.169)  // https://www.timeanddate.com/eclipse/lunar/2017-august-7
+        lunarFractionCase(2019,  7, 16, 0.654)  // https://www.timeanddate.com/eclipse/lunar/2019-july-16
+        lunarFractionCase(2021, 11, 19, 0.991)  // https://www.timeanddate.com/eclipse/lunar/2021-november-19
+        lunarFractionCase(2023, 10, 28, 0.060)  // https://www.timeanddate.com/eclipse/lunar/2023-october-28
+        lunarFractionCase(2024,  9, 18, 0.035)  // https://www.timeanddate.com/eclipse/lunar/2024-september-18
+        lunarFractionCase(2026,  8, 28, 0.962)  // https://www.timeanddate.com/eclipse/lunar/2026-august-28
+        lunarFractionCase(2028,  1, 12, 0.024)  // https://www.timeanddate.com/eclipse/lunar/2028-january-12
+        lunarFractionCase(2028,  7,  6, 0.325)  // https://www.timeanddate.com/eclipse/lunar/2028-july-6
+        lunarFractionCase(2030,  6, 15, 0.464)  // https://www.timeanddate.com/eclipse/lunar/2030-june-15
     }
 
     //----------------------------------------------------------------------------------------

Diff for: source/python/setup.py

@@ -2,7 +2,7 @@
 
 setup(
     name='astronomy-engine',
-    version='2.1.6',
+    version='2.1.7',
     description='Astronomy calculation for Sun, Moon, and planets.',
     long_description=open('README.md').read(),
     long_description_content_type='text/markdown',