fixes #1557: Filter out emojis when creating short names (#1578)

* Filter out emojis from text when finding initials

* Confirm non-English non-emoji unicde isn't filtered

* Remove unused example unit test

---------

Co-authored-by: James Rich <2199651+jamesarich@users.noreply.github.com>

app/src/main/java/com/geeksville/mesh/model/UIState.kt

@@ -86,13 +86,13 @@ import javax.inject.Inject
 import kotlin.math.roundToInt
 
 // Given a human name, strip out the first letter of the first three words and return that as the initials for
-// that user. If the original name is only one word, strip vowels from the original name and if the result is
-// 3 or more characters, use the first three characters. If not, just take the first 3 characters of the
-// original name.
+// that user, ignoring emojis. If the original name is only one word, strip vowels from the original
+// name and if the result is 3 or more characters, use the first three characters. If not, just take
+// the first 3 characters of the original name.
 fun getInitials(nameIn: String): String {
     val nchars = 4
     val minchars = 2
-    val name = nameIn.trim()
+    val name = nameIn.trim().withoutEmojis()
     val words = name.split(Regex("\\s+")).filter { it.isNotEmpty() }
 
     val initials = when (words.size) {
@@ -109,6 +109,8 @@ fun getInitials(nameIn: String): String {
     return initials.take(nchars)
 }
 
+private fun String.withoutEmojis(): String = filterNot { char -> char.isSurrogate() }
+
 /**
  * Builds a [Channel] list from the difference between two [ChannelSettings] lists.
  * Only changes are included in the resulting list.

app/src/test/java/com/geeksville/mesh/ExampleUnitTest.kt

@@ -1,34 +0,0 @@
-/*
- * Copyright (c) 2025 Meshtastic LLC
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <https://www.gnu.org/licenses/>.
- */
-
-package com.geeksville.mesh
-
-import org.junit.Test
-
-import org.junit.Assert.*
-
-/**
- * Example local unit test, which will execute on the development machine (host).
- *
- * See [testing documentation](http://d.android.com/tools/testing).
- */
-class ExampleUnitTest {
-    @Test
-    fun addition_isCorrect() {
-        assertEquals(4, 2 + 2)
-    }
-}

app/src/test/java/com/geeksville/mesh/ui/UIUnitTest.kt

@@ -18,22 +18,25 @@
 package com.geeksville.mesh.ui
 
 import com.geeksville.mesh.model.getInitials
-import org.junit.Assert
+import org.junit.Assert.assertEquals
 import org.junit.Test
 
-/**
- * Example local unit test, which will execute on the development machine (host).
- *
- * See [testing documentation](http://d.android.com/tools/testing).
- */
 class UIUnitTest {
     @Test
     fun initialsGood() {
-        Assert.assertEquals("KH", getInitials("Kevin Hester"))
-        Assert.assertEquals("KHLC", getInitials("  Kevin Hester Lesser Cat  "))
-        Assert.assertEquals("", getInitials("  "))
-        Assert.assertEquals("gksv", getInitials("geeksville"))
-        Assert.assertEquals("geek", getInitials("geek"))
-        Assert.assertEquals("gks1", getInitials("geeks1"))
+        assertEquals("KH", getInitials("Kevin Hester"))
+        assertEquals("KHLC", getInitials("  Kevin Hester Lesser Cat  "))
+        assertEquals("", getInitials("  "))
+        assertEquals("gksv", getInitials("geeksville"))
+        assertEquals("geek", getInitials("geek"))
+        assertEquals("gks1", getInitials("geeks1"))
+    }
+
+    @Test
+    fun ignoreEmojisWhenCreatingInitials() {
+        assertEquals("TG", getInitials("The \uD83D\uDC10 Goat"))
+        assertEquals("TT", getInitials("The \uD83E\uDD14Thinker"))
+        assertEquals("TCH", getInitials("\uD83D\uDC4F\uD83C\uDFFFThe Clapping Hands"))
+        assertEquals("山羊", getInitials("山羊\uD83D\uDC10"))
     }
 }