Fixes UTF-32 Reactions

app/src/test/java/com/vitorpamplona/amethyst/CharsetTest.kt

@@ -0,0 +1,37 @@
+package com.vitorpamplona.amethyst
+
+import com.vitorpamplona.amethyst.service.firstFullChar
+import org.junit.Assert
+import org.junit.Test
+
+class CharsetTest {
+    @Test
+    fun testASCIIChar() {
+        Assert.assertEquals("H", "Hi".firstFullChar())
+    }
+
+    @Test
+    fun testUTF16Char() {
+        Assert.assertEquals("\uD83C\uDF48", "\uD83C\uDF48Hi".firstFullChar())
+    }
+
+    @Test
+    fun testUTF32Char() {
+        Assert.assertEquals("\uD83E\uDDD1\uD83C\uDFFE", "\uD83E\uDDD1\uD83C\uDFFEHi".firstFullChar())
+    }
+
+    @Test
+    fun testAsciiWithUTF32Char() {
+        Assert.assertEquals("H", "Hi\uD83E\uDDD1\uD83C\uDFFEHi".firstFullChar())
+    }
+
+    @Test
+    fun testBlank() {
+        Assert.assertEquals("", "".firstFullChar())
+    }
+
+    @Test
+    fun testSpecialChars() {
+        Assert.assertEquals("=", "=x".firstFullChar())
+    }
+}